M2M+Unit+III+Practice+Questions

toc //The following are student-developed test questions taken from the Learning Objectives.// =Questions (answers at bottom of page):=

__**1. Molecular Basis of Carcinogenesis I, II, & III**__
1.1 Which of the following is **__not__** a phenotype of malignant cancer cells? > a) They are clonal in origin (ie they all descend from a single cell). > b) They are capable of shedding cells that can drift through the circulatory system to other places in the body. > c) They all depend on stroma to proliferate. > d) The lack much of the structure and many of the functions of the tissue they derived from.

1.2 Cancer cells that proliferate to distant sites in the body are called:

> a) Paranchymal > b) Invasive > c) Mitogenic > d) Metastatic > e) Tetrameric

1.3 A benign tumor is made of cells that:

> a) Have lost the specialized function of the tissue they are derived from. > b) Are metastatic. > c) Are Invasive. > d) Exhibit the BRC-ABL ectodomain.

1.4 For a cell to change from a normal to neoplastic state, changes in cellular heredity must be involved:

> a) True > b) False

1.5 Cancer is mainly:

> a) A familial, genetic disease. > b) A disease caused by exposure to environmental factors. > c) A disease of the rich. > d) Caused by viruses.

1.6 Which of the following is an oncogene whose malfunction results in Chronic Myelocytotic Leukemia?

> a) BCR-ABL > b) BRCA1 > c) RB gene > d) The gene encoding p53

1.7 In individuals heterozygous for a mutated tumor suppressor gene, cancer most likely the result of what?

> a) Inadequate protein product. > b) Loss of heterozygosity. > c) Novel function of the mutated gene product. > d) Immune response to the mutated gene product.

1.8 Which of the following is not an example of a cancer susceptibility that is inherited in an autosomal dominant fashion?

> a) Adenomatous Polypsis (FAP-APC gene) > b) Familial Retinoblastoma (RB gene) > c) Xeroderma Pigmentosum (ERCC4) > d) Familial Breast and Ovarian Cancer (BRCA1 & BRCA2)

1.9 Which of the following perform a similar function to RB protein?

> a) cyclin D and cyclin E > b) protein E6 and protein E7 > c) p107 and p130 > d) CDK 4, CDK 6, and CDK 2

1.10 Which of the following implies familial inheritance of retinoblastoma?

> a) Bladder cancer > b) An observable mutation on chromosome 14 > c) Bilateral retinoblastoma > d) Presence of HPV protein E7 in the cell

1.11 The RB protein arrests the cell in which phase of the cell cycle?

> a) Between G1 and S > b) Between S and G2 > c) Between G2 and M > d) Between M and G1 > e) The RB protein does not function by arresting the cell cycle

1.12 Which of the following is not involved in the APC ( __[|Familial adenomatous polyposis]__) pathway?

> a) Frizzled > b) Wnt > c) β-catenin > d) N-myc

1.13 Which is **__not__** a function of the BRCA1 & BRCA2 proteins?

> a) Non-homologous end joining > b) Regulation of the S-phase checkpoint > c) Regulation of the G2/M phase checkpoint > d) Homologous recombination

1.14 In cancer, which one of these genes is __**not**__ primarily mutated due to a frameshift mutation?

> a) p53 > b) APC > c) ATM > d) BRCA1

1.15 Mutant p53 does which of the following:

> a) Forms an insoluble plaque that damages DNA. > b) "Poisons" the p53 tetramer. > c) Causes the breakdown of ATM. > d) Does nothing until the wild-type allele is mutated.

1.16 Viral oncogenes:

> a) Evolved independently from humans. > b) Are more efficient than the human genes they resemble. > c) Are responsible for 20-25% of breast cancers. > d) Cause "double minutes" to arise.

1.17 In treating people with the BCR-ABL (Philadelphia Chromosome) mutation, Gleevac resembles:

> a) ATP > b) NADH > c) p53 > d) v-sarc

1.18 Herceptin is:

> a) A synthetic antibody that attacks HER2/ERBB2 receptors. > b) A synthetic tyrosine kinase inhibitor. > c) A viral oncogene. > d) A drug that is successful in combating multiple kidney tumors.

__**2. Von Hippel-Lindau Clinical Vignette**__
2.1 Von Hippel-Lindau is:

> a. Autosomal Dominant > b. Autosomal Recessive > c. X-linked recessive > d. A somatic mutation

2.2 In Von Hippel-Lindau, which of the following are found in the cerebellum, spinal cord, kidney and retina?

> a. Sarcomas > b. Adenomas > c. Hemangioblastomas > d. Lymphomas

2.3 The VHL gene is a/an:

> a. Oncogene > b. Tumor suppressor > c. Transcription factor > d. Mutation in the BCR gene

__**3. Membrane Structure**__
3.1 Compared to the plasma membrane, how much surface area do the internal membranes of a typical cell have?

> a. The same amount (700μm²) > b. 10x more (7000μm²) > c. 100x more (70000μm²) > d. 1/10th as much (70μm²)

3.2 If a cell seems to be packed with rough ER, what is probably its primary purpose?

> a. Breakdown of toxins > b. Primarily structural > c. Production and excretion of proteins > d. It's an epithelial skin cell

3.3 In cell fractionation by centrifugation, which is the correct order in which the cellular components will settle?

> a. Nuclei, then ribosomes, then mitochondria > b. Cytoskeletons, then lysosomes, then ribosomes > c. Nuclei, then mitochondria, then cytoskeletons > d. Mitochondria, then ribosomes, then nuclei

3.4 A lipid bilayer is:

> a. A static, solid structure. > b. Usually around 5 nm or so thick. > c. Typically devoid of proteins. > d. A temporary structure that usually devolves into a sheet-like structure if left alone.

3.5 Which of the following is **__not__** one of the three main classes of lipids found in cellular membranes?

> a. Sphingolipids > b. Cholesterol > c. Phosphoglycerides > d. Myelolipids

3.6 A substance that demonstrates both a polar and non-polar region (like a phospholipid) is called:

> a. Amphipathic > b. Amphoteric > c. Amphibian > d. Amphibolic

3.7 All three classes of cellular membrane lipids are synthesised:

> a. In the rough ER. > b. In the smooth ER. > c. By ribosomes in the cytosol. > d. In peroxisomes.

3.8 Which of the following is not a component of a phosphogylceride:

> a. Polar head group > b. Glycerol > c. Phosphate > d. A trio of fatty acyl chains

3.9 A sphingolipid is made of:

> a. A ceramide, sphingosine, and a head group > b. A sphingosine, two fatty acid tails, and a head group > c. A ceramide, two fatty acid tails, and a head group > d. A ceramide and a head group

3.10 Cholesterol is composed of:

> a. A polar head group, rigid steroid ring structure, and a nonpolar hydrocarbon tail > b. A nonpoalar head group, rigid steroid ring structure, and a polar hydrocarbon tail > c. A polar head group, flexible steroid ring structure, and a nonpolar hydrocarbon tail > d. A nonpoalar head group, flexible steroid ring structure, and a polar hydrocarbon tail

3.11 Cholesterol does what in the plasma membrane:

> a. Increases membrane fluidity > b. Acts as an extra-cellular receptor > c. Serves to prevent proteins on the basal surface of the cell from reaching the apical surface. > d. Increases plasma membrane thickness

3.12 Which of the following is true regarding phospholipids?

> a. They are static to one another in the plasma membrane. > b. They are composed entirely of saturated fatty acids. > c. They require an ATP-driven flipase to transfer from one membrane leaflet to another. > d. They exist as a monolayer when they exist as part of a cellular membrane.

3.13 Which of the following is true regarding "Lipid rafts" in the plasma membrane?

> a. They serve as areas of increased plasma membrane fluidity. > b. They serve as areas of thinness in the plasma membrane. > c. They serve to anchor organelles to the phospholipid bilayer. > d. They contain a higher population of signaling molecules than other parts of the plasma membrane.

3.14 In the presence of cholesterol, INSIG binds to:

> a. SCAP > b. SREBP > c. S2P > d. bHLH

3.15 Which of the following is a transcription factor that increases cholesterol synthesis and the expression of LDL receptors?

> a. SCAP > b. SREBP > c. INSIG > d. OMPLA

__**4. Composition of Cells**__
4.1 Which of the following represents the abundance of molecules in the body by number?

> a. Water 98%, Simple Inorganic Molecules (NA+, K+, CL-) 2%, Everything else (carbohydrates, proteins, nucleic acids, lipids, etc) 0.2% > b. Water 99%, Simple Inorganic Molecules (NA+, K+, CL-) 0.5%, Everything else (carbohydrates, proteins, nucleic acids, lipids, etc) 0.5% > c. Water 99%, Simple Inorganic Molecules (NA+, K+, CL-) 1%, Everything else (carbohydrates, proteins, nucleic acids, lipids, etc) 0.2% > d. Water 90%, Simple Inorganic Molecules (NA+, K+, CL-) 10%, Everything else (carbohydrates, proteins, nucleic acids, lipids, etc) 0.2%

4.2 Which of the following is true?

> a. Sodium is more concentrated in the ICF than the ECF > b. Potassium is more concentrated in the ICF than the ECF > c. Big anions are more concentrated in the EFC than the ICF > d. Water is more concentrated in the ICF than the ECF

4.3 Chloride and Bicarbonate are more concentrated in the ECF than the ICF for what main reason?

> a. The plasma membrane is impermeable to Cl- and HCO3- ions. > b. The inside of the cell is primarily negative in charge. > c. The presence of calcium ions in the cell repels them. > d. The cell actively pumps them out.

4.4 Which of the following is true?

> a. Primary active transport depends on Na+ molecules leaking into the cell. > b. Secondary active transport depends on ATP to move molecules across the plasma membrane. > c. Transporters are thousands of times faster than channels. > d. Transporters are used to move ions against an energy gradient.

__**5. Cell Volume Regulation**__
5.1 Rapid administration of insulin to a patient whose blood glucose concentration is very high can result in which of the following:

> a. Clysis > b. Cerebral edema > c. A safe return to homeostatic levels of blood glucose levels > d. A change in the reflection coefficient of brain cells

5.2 Which of the following is not one of the 3 methods used by cells in nature to keep from swelling and bursting?

> a. Rigid cell walls > b. Water pumps > c. Maintenance of solute concentration on both sides of the plasma membrane > d. Impermeability to water

5.3 What is the difference between osmosis and diffusion?

> a. Osmosis refers to the diffusion of water. > b. Osmosis refers to the presence of a semi-permeable membrane. > c. Osmosis is the movement of solvent into a cell and diffusion refers to movement out of a cell > d. Diffusion only refers to a certain class of charged particles

5.4 What do the terms π and ΔC refer to in the equation "π = σRTΔC"?

> a. Reflection coefficient and difference in solute concentration > b. Tonicity and difference in solute concentration > c. Reflection coefficient and change in osmotic pressure > d. Osmotic pressure and change in solute concentration

5.5 Which of the following is false?

> a. Osmolarity refers to the difference in solute concentration inside and outside of a cell, regardless of what is permeable to the membrane. > b. The reflection coefficient refers to the effects caused by the rate of solute diffusion across the cell membrane. > c. Tonicity refers to the relative solute concentrations inside and outside of the cell, while taking into account the permeability of solutes. > d. In a cell that is 300 mosM for protein, an environment that is 300 mM NaCl is isotonic.

5.6 Any solution that makes a cell shrink is:

> a. Hyperosmotic > b. Hypoosmotic > c. Hypotonic > d. Hypertonic

__**6. Membrane Potential I, II, & III**__
[|Membrane Potential Problems]

6.1 The Donnan rule states:

> a. E = 60/z * log(X_outside/X_inside) > b. [K_inside][Cl_inside] = [K_outside][Cl_outside] > c. Bulk solutions are neutral. > d. I before E, except after C, except in "neighbor" and "weigh."

6.2 What is the __**primary reason**__ for the high concentration of K+ and low concentration of Na+ in the IFC?

> a. The Na+/K+ pump maintains these concentrations > b. The relative electron affinity of K+ and Na+ > c. The difference in cell membrane permeability for these two ions > d. The net negative charge inside of the cell has a greater attraction to K+ than Na+

6.3 Why is it possible that the Na+ concentration inside of a cell may be very low (compared to K+) even though the driving force is very high?

> a. Na+ is repelled by the presence of K+ inside of the cell. > b. The concentration of Na+ inside and outside of the cell are almost equal and any slight fluctuation makes a large different in the electrochemical gradient. > c. The relative permeability of sodium is much lower than that of potassium. > d. The dissociation constant of NaCl is too low to allow enough Na+ to get into the cell

6.4 The ECF concentration of Na+ is 100 and the ICF concentration of Na+ is 1. What is E Na ?

> a. It is impossible to tell without knowing the K+ concentrations. > b. 60 mV > c. 120 mV > d. E Na is always +70 mV.

6.5 If E Cl- =-80 mV and V m =-70 mV, is there a Cl- pump? And, if there is, which way is it pumping?

> a. There is no pump. > b. There is a pump and it is pumping Cl- out > c. There is a pump and it is pumping Cl- in > d. What?

6.6 A large drop in extra-cellular Na+ concentration has what consequences to the Vm?

> a. The cell membrane will rapidly depolarize. > b. The Vm will ever-so-slightly approach E K+ > c. The Vm will ever-so-slightly approach E Na+ > d. The Vm will rapidly increase due to the un-matched Cl- ions that now reside outside of the cell membrane

6.7 You are given concentrations of Na+ & K+ in the ICF and ECF as well as the relative permeability of the two ions. How do you find the membrane potential?

> a. Nernst equation > b. Donnan relationship > c. Goldman equation > d. Henderson-Hasselbalch equation

**7. Acids, Bases, & Buffers**
[|Dr. Bentley's problems]

7.1 If (at equilibrium) K eq =.222, k f =2, [A]=3M, [B]=3M, and [C]=2M, what is [D] where A + B -> C + D?

> a. 1 > b. 2 > c. 3 > d. 4

7.2 If [OH-] is 10-5, what is the pH?

> a. 1 > b. 3 > c. 9 > d. 5

7.3 Which of the following are the clinical pH values for acidosis and alkalosis in ECF, respectively?

> a. 7.3 pH & 7.5 pH > b. 7 pH & 8 pH > c. 7.39 pH & 7.41 pH > d. 7.35 pH & 7.45 pH

7.4 An acid is left to reach equilibrium in in water. The resulting concentrations are: [H+] = 3 mM, [A-] = 3 mM, and [HA] = 25 mM. What is pKa?

> a. 0.44 > b. 0.48 > c. 9 > d. 175

7.5 Which of the following is the correct form of the Henderson-Hasselbalch equation?

> a. pH = pKa + log([A-]/[HA]) > b. pH = pKa - log([A-]/[HA]) > c. pKa = pH + log([A-]/[HA]) > d. pKa = pH * log([A-]/[HA])

7.6 If the solution in which an acid resides is at a pH below the pKa of that acid, which of the following is true?

> a. The acid will primarily not be disassociated (intact, e.g. HA). > b. The acid will primarily be disassociated (e.g. H+ & A-). > c. You can tell nothing about the association of the acid based on this relationship. > d. None of the above.

7.7 Which of the following is the correct form of the Henderson-Hasselbalch equation as it applies to CO2/Bicarb buffering?

> a. pH = 6.3 + log [HCO 3 - ]mM/ .01P co 2 mmHg > b. pH = 6.1 + log [HCO 3 - ]mM/ .03P co 2 mmHg > c. pH = 6.3 + log [HCO 3 - ]mM/ .03P co 2 mmHg > d. pH = 6.1 + log [HCO 3 - ]mM/ .01P co 2 mmHg

7.8 Which of the following is incorrect?

> a. Normal arterial blood pH: 7.34-7.44 > b. Normal venous blood ph: 7.38-7.52 > c. Normal concentration of HCO3- in blood: 24 mM > d. Normal PCO2 in blood: 40 mm Hg > e. Normal concentration of CO2 in blood: 1.2 mM

7.9 Which is the best guestimate of a buffering range of a buffer?

> a. 0.001 mM. > b. +/- 1 pH around the pKa of the buffer. > c. The inverse of the pKa. > d. This number varies based on the current position of the titration curve.

7.10 Which of the following amino acids has a side chain that can protonate/deprotonate at physiological pHs?

> a. Lysine > b. Serine > c. Cysteine > d. Histidine

**8. Membrane Fusion**
8.1 Which of the following is not a SNARE protein?

> a. Syntaxin > b. SNAP-25 > c. VAMP > d. β-catenin

8.2 All target membranes contain which two SNARE proteins?

> a. Syntaxin & VAMP > b. VAMP & SNAP-25 > c. Syntaxin & SNAP-25 > d. VAMP & Sec1

8.3 Which of the following is a hexameric protein that disassembles a SNARE complex?

> a. NSF > b. syn5 > c. TGN > d. n-Sec1

8.4 In order to enter a cell, a enveloped virus uses:

> a. The SNARE complex. > b. A single viral protein that unfolds and stabs one end of its binding protein into the membrane of the target cell. > c. A targeted release of H+. > d. Diffusion down its concentration gradient.

**9. Membrane Transporters**
9.1 Glucose is trapped inside of a cell by which mechanism?

> a. The negative charge inside of the cell attracts glucose molecules > b. Glucose stays because it is energetically favorable due to the concentration gradient. > c. Glucose is sequestered as G6P which cannot be transported out by the glucose transporter protein. > d. Glucose is phagocytized by the cell.

9.2 The Na/K pump is an example of what?

> a. Primary Active Transport > b. Secondary Active Transport > c. Passive Diffusion > d. Co-transport

9.3 Calcium ions in the cytoplasm signal all of the following, except:

> a. Muscle contraction > b. Cellular Excretion > c. Apoptosis > d. Glucose uptake

9.4 Which of the following is not an effective treatment for hyperkalemia?

> a. Calcium ion > b. Bicarbonate ion > c. Insulin + Glucose > d. Kayexelate > e. Dialysis > f. All of the above are effective treatments

**11. MS Vignette**
1. MS is diagnosed by:

> a. Lesions disseminated in time. > b. Atleast two lesions in different places in the CNS. > c. Abnormalities in the neurological exam. > d. All of the above.

2. Which of the following is true?

> a. MS can cause lesions that can break the blood/brain barrier. > b. Demyelination can increase amplitude of action potentials. > c. Schwan cells myelinate multiple neurons in the CNS. > d. Oligodendrocytes myelinate a single neuron in the PNS.

3. Which of the following is true about a CSF analysis in a person with MS?

> a. Protein usually > 110 mg/dL > b. WBC frequently > 40/mm3 > c. Abnormal Glucose > d. Abnormal presence of immunoglobulins

//Note: Need more questions regarding Sodium channel blockade and treatment options//.

**12. Epithelial Transport**
12.1 Which of the following types of epithelia can make use a pericellular shunt pathway?

> a. Epithelia with truly tight junctions > b. Epithelia with leaky tight junctions > c. Epithelia in sweat glands > d. Epithelia of the distal parts of kidney tubules

12.2 Which of the following are examples of epithelia with "tight" tight junctions?

> a. Epithelia of the small intestine > b. Epithelia junctions of the large intestine > c. Epithelia that need to maintain large energy gradients > d. Epithelia of the gall bladder

12.3 Nearly all cellular transport is done by:

> a. ATP-driven pumps (primary active transport) > b. Secondary active transport involving Na+ > c. Endocytosis > d. Pinocytosis

12.4 Which of the following is the main cellular transport mechanism for H+?

> a. ATP-driven pumps (primary active transport) > b. Secondary active transport involving Na+ > c. Endocytosis > d. Gas exchange in the lungs

12.5 The apical solution is _ compared to the basolateral solution?

> a. Positive > b. Neutral > c. Negative > d. Can be any charge

12.6 Voltage potentials are written:

> a. As the potential of the inside of the cell with respect to the oustide. > b. As the potential of the outside of the cell with respect to the inside. > c. Without respect to the inside or outside of the cell (it ends up being the same mathematically). > d. All of this voltage potential stuff is made up without rhyme or reason.

12.7 Which of the following is not a method in which ions are absorbed into the interstitial fluid from the lumen?

> a. Apical Na+ and Cl- channels, Basilar Na+/K+ pump and Cl- channels > b. Apical Na+ channels, pericellular Cl- shunt, basilar Na+/K+ pump > c. Na/K/2Cl apical cotransporter, Basilar Na+/K+ pump and Cl- channels > d. Apical charge mediated pinocytosis, Basilar Na+/K+ pump and Cl- channels

12.8 The major cellular defect in cholera is:

> a. Overproduction of acetyl choline. > b. Overproduction of cAMP. > c. A defective apical Na/K pump. > d. A defective apical Cl- channel.

12.9 Which of the following is false?

> a. In epithelia, sugar and amino acids cannot enter the cell if they are not accompanied by Na+. > b. In epithelia, the movement of Na+ into the cell is reduced if no extracellular sugar of amino acids are present. > c. The transport mechanism of glucose in epithelial cells and in muscle cells is similar. > d. The kidney and the GI tract absorb amino acids and glucose in a similar fashion. > e. In epithelial cells, apical membrane proteins may not freely diffuse to the basolateral membrane.

12.10 What will happen if you eat a bunch of glucose without any NaCl?

> a. You will not be able to absorb the glucose. > b. You will absorb the glucose in the absence of NaCl by using analogous ions. > c. NaCl leak into the lumen through leaky (shunt) junctions so that you may absorb the glucose. > d. NaCl diffuse out of the cell and into the lumen so that you may absorb the glucose.

12.11 How do epithelial cells regulate how much of a nutrient they absorb?

> a. By closing Na+ channels. > b. By closing nutrient specific channels. > c. By using an ATP-driven mechanism to pump the nutrients back into the lumen. > d. They don't.

12.12 What will happen if you eat a bunch of L-glucose?

> a. The same thing as eating R-glucose. > b. It will damage your kidneys during excretion. > c. It will cause diarrhea by drawing water into the lumen. > d. The epithelial cells will convert the L-glucose into R-glucose.

12.13 Water always moves passively into cells, which of the following epithelial cells is impermeable to water?

> a. GI tract epithelium > b. Sweat gland epithelium > c. Muscle cells > d. None of the above

12.14 How much of the total metabolic waste a person makes in a day (15 moles) is composed of H+?

> a. Almost all of it (14.5 M). > b. Little of it (.450 M). > c. Very little of it (.050 M). > d. The body does not get rid of H+ ions because they are used in mitochondria.

12.15 The kidney functions by:

> a. Pumping urea and other wastes out of the blood. > b. Passively diffusing urea and other wastes out of the blood. > c. Pumping blood through a filter at pressure to get an ultrafiltrate of good stuff and bad stuff. > d. Pumping K+ out of the blood plasma and letting the urea follow.

12.16 Which of the following is not true of the GI tract?

> a. The GI tract excretes about 30 mM of metabolic waste per day. > b. The GI tract is very specific about the molecules it absorbs. > c. The GI tract breaks down the normally harmless butulinum toxin into a poisonous micro-protein before absorbing it. > d. The GI tract excretes highly toxic RBC breakdown products.

12.17 CFTR is:

> a. A regulator of the Cl- channel that is broken in people with CF. > b. Cl- channel that is broken in people with CF. > c. A transcription factor of a gene that codes for a protein in the Cl- channel. > d. A malfunction in the Na/2Cl/K pump on the basolateral surface of epithelial cells.

**13. Action Potential I, II, & III**
13.1 As an action potential reaches the terminal end of the pre-synaptic neuron, ions channels open and let which substance into the cytoplasm in order to cause the fusion of excretory vesicles to the cell membrane (so that they can release their contents into the synaptic cleft)?

> a. Glutamate > b. Sodium > c. Calcium > d. Potassium

13.2 What keeps an action potential from withering away during conduction down a neuron?

> a. Accommodation > b. Voltage-gated sodium channels > c. The absolute refractory period > d. Open ion channels

13.3 What is the ratio of Na current to K current at threshold?

> a. 75:25 > b. 50:50 > c. 25:75 > d. Irrelevant

13.4 In general, compared to large axons, small axons:

> a. Are capable of firing more between rest periods. > b. Are more resistant to external stimulation. > c. Have a faster action potential > d. Are more difficult to block with anasthetic (m gates more difficult to block). > e. Accommodate more slowly.

13.5 Which of the following is considered a large nerve fiber?

> a. A pain fiber. > b. A temperature fiber. > c. A touch fiber. > d. None of the above.

13.5 A myelinated fiber conducts faster because myelin:

> a. increases capacitance and decreases resistance of nerve fibers membranes. > b. decreases capacitance and decreases resistance of nerve fibers membranes. > c. decreases capacitance and increases resistance of nerve fibers membranes. > d. increases capacitance and increases resistance of nerve fibers membranes.

**14. DKA Vignette**
14.1 Which of the following is not a step in insulin release?

> a. Glucose is brought into the ß-cell via a passive carrier. > b. Intracellular K is exchanged with extracellular H+ > c. Cell depolarization causes Ca voltage-gated channels to swing open > d. An increase in cellular ATP to ADP ratio causes inhibition of a K channel.

14.2 Which of the following is true of DKA?

> a. Mannitol can be used to remove excess K from the blood. > b. Starving cells make use of lipolysis for fuel which creates ketone bodies. > c. Cerebral edema is more often seen as a complication of DKA in adults than in children. > d. During episodes of DKA, total body potassium levels are high.

14.3 Which of the following is not frequently a symptom of DKA?

> a. Kussmaul respirations > b. Altered conciousness > c. Peak T-waves on ECG > d. Polyuria > e. Nausea

**15. Secretory Pathways I & II**
15.1 Signal recognition proteins have an abundance of which amino acid at its signal sequence binding pocket?

> a. Arginine > b. Mescaline > c. Cysteine > d. Methionine

15.2 How is Rough ER protein synthesis regulated?

> a. It is not. > b. It is regulated by the ribosome on the cytoplasmic side > c. It is regulated by a chaperonin on the lumenal side > d. It is regulated by both a chaperonin and the ribosome

15.3 Which end (on either side of the transmembrane domain) of the nascent protein will stick into the ER lumen in a type II protein?

> a. The side with a positively charged patch > b. The N-terminal end > c. The C-terminal end > d. None of the above

15.4 In the Rough ER/Golgi, which of the following amino acids is involved with N-linked glycosylation? Which are O-linked?

> a. Alanine; Cysteine, Methionine > b. Asparagine; Serine, Tryptophan > c. Asparagine; Serine, Threonine > d. Arginine; Serine, Histidine

15.5 Which of the following sequences must be present in order for a protein to be glycosylated with the core glycosylation during post-translational modification in the rough ER?

> a. asn-something-ser-thr > b. asn-something-ser/thr > c. asn-something-ser-something-thr > d. asn-ser-something-thr

15.6 A protein that is linked to a rough ER membrane by a GPI anchor will eventually end up where?

> a. On the outer leaflet of the plasma membrane > b. On the inner leaflet of the plasma membrane > c. In the cytosol > d. On the nuclear envelop

15.7 Which of the following is not a secretory pathway for proteins in a cell?

> a. Using a receptor protein to carry another protein from the cytosol into the membrane through a pore complex. > b. Using a translocon to move a protein across a membrane. > c. Using a membrane, adaptor proteins, and coat proteins to form vesicles that carry the contents to different cellular location. > d. All of the above are secretory pathways for proteins in a cell.

15.8 Which of the following is not a function of the ER.

> a. Lipid synthesis > b. Placement of disulfide bonds onto proteins > c. Cholesterol homeostasis > d. Synthesis of complex sphingolipids from a ceramide backbone

15.9 Which of the following is false?

> a. Proteins are left in the cytosol or directed to the ER based on specific 5' sequences > b. Co-translational translocation is the process of moving a maturing protein from the cis-golgi to the trans-golgi > c. Protein cleavage is a major function of the golgi complex > d. Transmembrane proteins can be sorted into transport vesicles based on vesicle thickness.

15.10 Which of the following molecules provides the energy to make clathrin-coated vesicles naked?

> a. ATP > b. GTP > c. NADH > d. FADH

15.11 Dynamin is:

> a. A cargo receptor > b. An adaptor between a cargo receptor and a clathrin molecule > c. A type of clathrin molecule > d. A 'pinchase' that pinches a vesicle off of a membrane

15.12 Which one of the following coats is responsible for retrograde movement of proteins in the ER/Golgi?

> a. Clathrin > b. COPI > c. COPII > d. None of the above

**16. Cholera Vignette**
16.1 The current (7th) cholera pandemic is caused by which strain of Cholera?

> a. Classical (O1) > b. El Tor (O1) > c. Bengal (O139) > d. O1N1

16.2 Which of the following is not a symptom of cholera?

> a. Grey, cloudy stool > b. Mid-epigastric pain > c. Vomiting > d. Severe, rapid dehydration

16.3 Cholera is spread via:

> a. Airborne droplets > b. Direct person-to-person contact > c. Saliva > d. Fecal-oral route

16.4 Approximately, how many Vibrio Cholerae bacteria must one ingest to become infected?

> a. 10 > b. 100,000 > c. 1,000,000 > d. 100,000,000

16.5 In cholera toxin, which of the following is true?

> a. Both A and B subunits are toxic. > b. The A subunit is a transport molecule and the B subunit contains the toxic active site > c. The B subunit is a transport molecule and the A subunit contains the toxic active site > d. None of the above

16.6 Which ion or molecule over-activates the CTFR channel in cholera?

> a. GM1 ganglioside > b. Ca > c. cAMP > d. Cholera toxin directly attacks CTFR itself

16.7 Cholera causes which type of diarrhea?

> a. Secretory > b. Osmotic > c. Lumenal > d. None of the above

16.8 In an oral rehydration solution, if you had 10 mEq of Na, how much glucose would you want?

> a. 1 mmol > b. 10 mmol > c. 50 mmol > d. 100 mmol

**17. Nucleus & Nuclear Import/Export**
17.1 Which of the following sets of amino acids are found in the nuclear pore and help with the import and export of large molecules?

> a. Proline and Glycine > b. Phenylalanine and Glycine > c. Proline and Glutamine > d. Phenylalanine and Glutamine

17.2 Proteins destined for which of the following locations are folded before they arrive?

> a. Proteins destined for the nucleus > b. Proteins destined for the Rough ER > c. Proteins destined for a peroxisome > d. Proteins destined for a mitochondria

17.3 Which of the following is true?

> a. The nuclear pore complex is approximately the same size as a ribosome > b. Molecules smaller than 50,000 daltons may freely diffuse into the nucleus > c. A string of negative amino acids or a negative amino acid patch signal a protein for nuclear import > d. The nuclear pore complex functions to keep inner membrane proteins on the inner membrane and outer membrane proteins on the outer membrane of the nucleus.

17.4 Ran-GDP is:

> a. Exported from the nucleus down its concentration gradient. > b. Formed by using GAP to hydrolyze GTP in the cytosol. > c. Used alongside an exportin in order to remove cargo from the nucleus. > d. Used to export mRNAs from the nucleus.

17.5 Ribosomes are:

> a. Primarily assembled in the cytoplasm. > b. Made with proteins assembled in the cytoplasm. > c. Exported from the nucleus without the use of nuclear pores > d. None of the above.

**18. Protein Degradation**
18.1 HSP70:

> a. Is only found in the cytoplasm and in the nucleus. > b. Binds ATP in order to bind a "cap" protein. > c. Binds specifically to hydrophilic patches of proteins > d. Releases from its bound protein when it hydrolyzes ATP.

18.2 Which of the following is true?

> a. 80% of all proteins fold correctly without help from a chaperonin. > b. 30% of all proteins are folded with assistance from chaperonins like hsp60 and hsp70 > c. 60% of proteins are misfolded and subsequently digested by a proteosome. > d. None of the above.

18.3 Retrotranslocation is the process of:

> a. Multiubiquitinating proteins to target them for digestion in a lysosome. > b. Sending a mis-folded protein back through a translocon and into a cytoplasmic proteosome. > c. Adding lysine to the N-terminal end of a protein which does not contain a lysine residue in order to attach a ubiquitine to that protein. > d. Bringing the contents of a clathrin coated vesicle into contact with a lysosome.

18.4 UDP-Glc (a glucosyl transferase) does which of the following:

> a. Actives ubiquitine. > b. Transfers active ubiquitine to another enzyme which then places the ubiquitine on the lysine of the protein to be degraded. > c. Removes glycosylations from mis-folded proteins in the cytosol. > d. Continually transfers a sugar onto a misfolded protein to prevent that protein from exiting the ER via a COPII vesicle.

18.5 Proteosomes:

> a. Use ATP during cleavage reactions that are performed on unfolded proteins. > b. Are found in the cytosol, nucleus, and rough ER. > c. Have a caspase-like ß-1 subunit that cleaves after acidic amino acids > d. Have α subunits that regulate entry of proteins into the "death chamber" by binding hydrophilic regions of the protein being digested.

18.6 Which of the following enzymes is responsible for transferring an activated ubiquitin to a protein in order to target it for degradation?

> a. E1 > b. E2 > c. E3 > d. Lys-48

18.7 Which of the following are capable of breaking down large molecules (e.g. LDL) into basic cellular "building blocks?"

> a. Caveolae > b. Lysosomes > c. Early Endosomes > d. Autophages

**19. Hyperkalemia Vignette**
19.1 Which of the following is not a cause of hyperkalemia?

> a. ACE inhibitors > b. Rhabdomyolysis > c. DKA > d. Diarrhea

19.2 Which of the following is not a symptom of hyperkalemia?

> a. Headache > b. Weakness/Paralysis > c. Abnormal hearth rhythm > d. Nausea

19.3 Which of the following foods is low in K?

> a. Potatoes > b. Tomatoes > c. Avocados > d. Apples

**20. Cytoskeleton I & II**
20.1 A "9 + 2 array" describes the molecular structure of which cytoskeletal element?

> a. A microtubule > b. A microfilament > c. An intermediate filament > d. None of the above

20.2 Which of the following cytoskeletal elements is primarily responsible for cellular movement?

> a. Microtubules > b. Microfilaments > c. Intermediate filaments > d. None of the above

20.3 Which of the following proteins help to move the cargo of the Herpes Simplex virus toward the minus end of a microtubule in order to reach the cell nucleus?

> a. Kinesins > b. Dyneins > c. Myosin > d. Fimbrin

20.4 GTP favors growth of which of the following:

> a. Microtubules > b. Microfilaments > c. Intermediate filaments > d. Actin tetramers

20.5 Intermediate filaments are approximately how large in diameter?

> a. 25 nm (13 protofilaments) > b. 5-9 nm (double helix) > c. 10 nm (32 helical coils) > d. 1 nm (monofilament)

20.6 Epidermolysis bullosa symplex, a disease in which the skin is highly sensitive to mechanical stress and blisters easily, is due to a mutation in which of the following?

> a. Beta tubulin > b. Actin > c. Keratin > d. GFAP

20.7 Kartagener syndrome is frequently characterized by:

> a. Peripheral neuropathy > b. Thrombocytopenia > c. Absence of gyri in the brain > d. Situs inversus

20.8 Which of the following binds to and stabilizes microtubules?

> a. Colchicine > b. Vinblastine > c. Paclitaxel > d. Lysergic acid diethylamide

20.9 Which of the following polymerize the minus end of an actin strand?

> a. Rho proteins > b. ARP proteins > c. Rac > d. Cdc42

**21. Cell Signaling (Overview I & II)**
21.1 Which of the following methods of cell signaling do NOT require production of secreted protein?

> a. Contact-dependent > b. Paracrine > c. Endocrine > d. Synaptic

21.2 Calcium is an example of a: > a. node and a primary messenger > b. node and a secondary messenger > c. module and a primary messenger > d. module and a secondary messenger > e. None of the above

21.3 Phospholipase C (PLC) cleaves phosphatidyl inositol-bisphosphate (PIP2) to form two secondary messengers: > a. cytosolic inositol triphosphate (IP3) and cytosolic diacylglycerol (DAG) > b. cytosolic IP3 and membrane-bound DAG > c. membrane-bound IP3 and cytosolic DAG > d. membrane-bound IP3 and membrane-bound DAG

**26. Receptor Tyrosine Kinases**
26.1 Which of the following are required for receptor tyrosine kinase activation?

> a. Dimerization > b. Ligand binding > c. Autophosphorylation > d. All of the above > e. (a) and (b)

26.2 The SH2 domain of Grb2 binds to:

> a. Phosphorylated tyrosine residues on the receptor tyrosine kinase > b. Phosphorylated tyrosine residues on the guanosine nucleotide exchange factor Sos > c. Proline-rich sequence on the receptor tyrosine kinase > d. Proline-rich sequence on the guanosine nucleotide exchange factor Sos

26.3 The SH3 domain of Grb2 binds to:

> a. Phosphorylated tyrosine residues on the receptor tyrosine kinase > b. Phosphorylated tyrosine residues on the guanosine nucleotide exchange factor Sos > c. Proline-rich sequence on the receptor tyrosine kinase > d. Proline-rich sequence on the guanosine nucleotide exchange factor Sos

26.4 The function of Sos is to:

> a. Phosphorylate Ras > b. Activate Ras by attaching a GTP molecule > c. Inactivate Ras by hydrolyzing a GTP molecule > d. Bind to the SH3 domain of Grb2

26.5 Grb2 that is artificially targeted to the plasma membrane will result in consitutive activation of RAF.

> a. True > b. False

26.6 Which method is LEAST likely to determine likely outcome of Gefitinib treatment for lung cancer? > a. DNA sequencing > b. Fluorescence in situ hybridization > c. Karyotyping > d. Immunohistochemistry

26.7 Smoking confers __primary__ resistance to Gefitinib treatment for lung cancer because: > a. Cigarette smoke induces a conformational change in EGFR that prevents it from binding to Gefitinib > b. Cigarette smoke induces a conformational change in Gefitinib that prevents it from binding to EGFR > c. The carcinogens in tobacco smoke cause mutations in EGFR that prevents it from binding to Gefitinib > d. The carcinogens in tobacco smoke cause mutations in Ras, a gene downstream from EGFR

=**Answers:**=

**1. Molecular Basis of Carcinogenesis I, II, & III**
1.1 Which of the following is **not** a phenotype of malignant cancer cells? > a) They are clonal in origin (ie they all descend from a single cell). > b) They are capable of shedding cells that can drift through the circulatory system to other places in the body. > **c) They all depend on stroma to proliferate.** Remember they can reproduce in "soft augur." > d) The lack much of the structure and many of the functions of the tissue they derived from.

1.2 Cancer cells that proliferate to distant sites in the body are called:

> a) Paranchymal This are the non-structural cells in a tissue that do the work of that tissue > b) Invasive This means that the cancer enters neighboring structures > c) Mitogenic This means "to cause mitosis." > **d) Metastatic** > e) Tetrameric This describes a protein that consists of 4 subunits

1.3 A benign tumor is made of cells that:

> **a) Have lost the specialized function of the tissue they are derived from.** > b) Are metastatic. Not true of benign tumors. > c) Are Invasive. Not true of benign tumors. > d) Exhibit the BRC-ABL ectodomain. [|BCR-ABL] is the mutation responsible for CML, AML, & ALL. Ectodomain refers to a portion of a membrane protein that sticks out of the cell.

1.4 For a cell to change from a normal to neoplastic state, changes in cellular heredity must be involved:

> **a) True** A cancer is the result of a mutation (and probably two mutations at that--two hit hypothesis). > b) False

1.5 Cancer is mainly:

> a) A familial, genetic disease. Sometimes, but not "mainly." > **b) A disease caused by exposure to environmental factors.** > c) A disease of the rich. This refers to gout in that "rich" diets may contribute to the disease. > d) Caused by viruses. Sometimes, but not "mainly."

1.6 Which of the following is an oncogene whose malfunction results in Chronic Myelocytotic Leukemia?

> **a) BCR-ABL The only oncogene on the list, the BCR-ABL fusion protein is a protein kinase that is overexpressed in CML ** > b) BRCA1 Breast & Ovarian cancer > c) RB gene Retinoblastoma > d) The gene encoding p53 A whole bunch of stuff but not as specific to CML as BCR-ABL

1.7 In individuals heterozygous for a mutated tumor suppressor gene, cancer most likely the result of what?

> a) Inadequate protein product. > **b) Loss of heterozygosity.** > c) Novel function of the mutated gene product. > d) Immune response to the mutated gene product.

1.8 Which of the following is not an example of a cancer susceptibility that is inherited in an autosomal dominant fashion?

> a) Adenomatous Polypsis (FAP-APC gene) > b) Familial Retinoblastoma (RB gene) > **c) Xeroderma Pigmentosum (ERCC4)** This is autosomal recessive. > d) Familial Breast and Ovarian Cancer (BRCA1 & BRCA2)

1.9 Which of the following perform a similar function to RB protein?

> a) cyclin D and cyclin E These proteins are involved in the suppression of RB protein. > b) protein E6 and protein E7 E6 is the HPV protein that targets p53. E7 targets RB protein. > **c) p107 and p130** > d) CDK 4, CDK 6, and CDK 2 These proteins are involved in the suppression of RB protein.

1.10 Which of the following implies familial inheritance of retinoblastoma?

> a) Bladder cancer > b) An observable mutation on chromosome 14 The RB gene lives on chromosome 13 > **c) Bilateral retinoblastoma** > d) Presence of HPV protein E7 in the cell HPV protein E7 targets RB protein.

1.11 The RB protein arrests the cell in which phase of the cell cycle?

> **a) Between G1 and S** > b) Between S and G2 > c) Between G2 and M > d) Between M and G1 > e) The RB protein does not function by arresting the cell cycle

1.12 Which of the following is not involved in the APC ([|Familial adenomatous polyposis]__) pathway?__

> a) Frizzled > b) Wnt > c) β-catenin > **d) N-myc** This is a viral oncogene.

1.13 Which is **not** a function of the BRCA1 & BRCA2 proteins?

> **a) Non-homologous end joining** > b) Regulation of the S-phase checkpoint > c) Regulation of the G2/M phase checkpoint > d) Homologous recombination

1.14 In cancer, which one of these genes is **not** __primarily mutated due to a frameshift mutation?__

> **a) p53** 75% missense > b) APC > c) ATM > d) BRCA1

1.15 Mutant p53 does which of the following:

> a) Forms an insoluble plaque that damages DNA. > **b) "Poisons" the p53 tetramer.** > c) Causes the breakdown of ATM. > d) Does nothing until the wild-type allele is mutated. Note that this is true of several other tumor suppressors, though.

1.16 Viral oncogenes:

> a) Evolved independently from humans. > **b) Are more efficient than the human genes they resemble.** > c) Are responsible for 20-25% of breast cancers. This is the percent of breast cancers with "oncogene addiction" to the HER2/ERBB2 (epithelial growth factor) receptors. > d) Cause "double minutes" to arise.

1.17 In treating people with the BCR-ABL (Philadelphia Chromosome) mutation, Gleevac resembles:

> **a) ATP** > b) NADH > c) p53 > d) v-sarc

1.18 Herceptin is:

> a) **A synthetic antibody that attacks HER2/ERBB2 receptors.** > b) A synthetic tyrosine kinase inhibitor. > c) A viral oncogene. > d) A drug that is successful in combating multiple kidney tumors.

**2. Von Hippel-Lindau Clinical Vignette**
2.1 Von Hippel-Lindau is:

> **a. Autosomal Dominant** However, there must be a loss of heterozygosity (LOH) for tumors to appear. > b. Autosomal Recessive > c. X-linked recessive > d. A somatic mutation

2.2 In Von Hippel-Lindau, which of the following are found in the cerebellum, spinal cord, kidney and retina?

> a. Sarcomas > b. Adenomas > **c. Hemangioblastomas** > d. Lymphomas

2.3 The VHL gene is a/an:

> a. Oncogene > **b. Tumor suppressor** > c. Transcription factor > d. Mutation in the BCR gene

**3. Membrane Structure**
3.1 Compared to the plasma membrane, how much surface area do the internal membranes of a typical cell have?

> a. The same amount (700μm²) > **b. 10x more (7000μm²)** And the cytoskeleton has another order of magnitude higher surface area than that (94,000μm²). > c. 100x more (70000μm²) > d. 1/10th as much (70μm²)

3.2 If a cell seems to be packed with rough ER, what is probably its primary purpose?

> a. Breakdown of toxins > b. Primarily structural > **c. Production and excretion of proteins** > d. It's an epithelial skin cell

3.3 In cell fractionation by centrifugation, which is the correct order in which the cellular components will settle?

> a. Nuclei, then ribosomes, then mitochondria > **b. Cytoskeletons, then lysosomes, then ribosomes** Whole cells, nuclei, cytoskeletons; then mitrochondria, lysosomes & peroxisomes; then microsomes and small vesicles; then ribosomes, virii, and large macromolecules > c. Nuclei, then mitochondria, then cytoskeletons > d. Mitochondria, then ribosomes, then nuclei

3.4 A lipid bilayer is:

> a. A static, solid structure. It's is dynamic and fluid-like. > **b. On average, around 5 nm or so thick.** > c. Typically devoid of proteins. 30% of proteins are integral membrane proteins. > d. A temporary structure that usually devolves into a sheet-like structure if left alone. Is energetically favored to form sphere-like structures.

3.5 Which of the following is **not** one of the three main classes of lipids found in cellular membranes?

> a. Sphingolipids > b. Cholesterol > c. Phosphoglycerides > **d. Myelolipids**

3.6 A substance that demonstrates both a polar and non-polar region (like a phospholipid) is called:

> **a. Amphipathic** > b. Amphoteric Acts as both an acid and a base. > c. Amphibian Like a frog. > d. Amphibolic Equivocal; uncertain; changing; ambiguous.

3.7 All three classes of cellular membrane lipids are synthesised:

> a. In the rough ER. Makes proteins to be shipped out of the cell by the golgi > **b. In the smooth ER.** Smooth ER is primarily responsible for lipid synthesis > c. By ribosomes in the cytosol. Makes proteins that will remain in the cell > d. In peroxisomes. Breaks down fatty acids (and other things) with peroxides. Contrast with lysosomes that break down things with acidic hydrolases.

3.8 Which of the following is not a component of a phosphogylceride:

> a. Polar head group Choline was used as an example of a polar head group. > b. Glycerol Forms part of the glycerol 3-phosphate backbone > c. Phosphate Forms part of the glycerol 3-phosphate backbone > **d. A trio of fatty acyl chains** Should only have 2 fatty acyl chains

3.9 A sphingolipid is made of:

> a. A ceramide, sphingosine, and a head group There is already a sphingosine in the ceramide (which is a sphingosine + a fatty acid) > b. A sphingosine, two fatty acid tails, and a head group > c. A ceramide, two fatty acid tails, and a head group > **d. A ceramide and a head group** The two acyl tails of this membrane lipid come from the sphingoside (1 tail) and the fatty acid (second tail) in the ceramide.

3.10 Cholesterol is composed of:

> **a. A polar head group, rigid steroid ring structure, and a nonpolar hydrocarbon tail** > b. A nonpoalar head group, rigid steroid ring structure, and a polar hydrocarbon tail > c. A polar head group, flexible steroid ring structure, and a nonpolar hydrocarbon tail > d. A nonpoalar head group, flexible steroid ring structure, and a polar hydrocarbon tail

3.11 Cholesterol does what in the plasma membrane:

> a. Increases membrane fluidity Cholesterol decreases membrane fluidity > b. Acts as an extra-cellular receptor > c. Serves to prevent proteins on the basal surface of the cell from reaching the apical surface. This is primarily done by tight cellular junctions which act much like one of those plastic things that hold a six-pack together (where each can would be analogous to a cell). It would be difficult for a protein to move up the side of the can and onto the lid with the plastic thingy stopping it. > **d. Increases plasma membrane thickness**

3.12 Which of the following is true regarding phospholipids?

> a. They are static to one another in the plasma membrane. They diffuse very rapidly in the membrane (several mms per second) > b. They are composed entirely of saturated fatty acids. Some contain unsaturated (kinked) fatty acids > **c. They require an ATP-driven flipase to transfer from one membrane leaflet to another.** > d. They exist as a monolayer when they exist as part of a cellular membrane. They exist as a **bi**layer

3.13 Which of the following is true regarding "Lipid rafts" in the plasma membrane?

> a. They serve as areas of increased plasma membrane fluidity. They decrease fluidity. > b. They serve as areas of thinness in the plasma membrane. They serve as areas of increased thickness. > c. They serve to anchor organelles to the phospholipid bilayer. > **d. They contain a higher population of signaling molecules than other parts of the plasma membrane.**

3.14 In the presence of cholesterol, INSIG binds to:

> **a. SCAP** > b. SREBP Is bound to SCAP. > c. S2P NOT IN SLIDES but cleaves (in Golgi) the transcription factor of SREBP off so it can go to the nucleus. > d. bHLH NOT IN SLIDES but this is the transcription factor piece of SREBP

3.15 Which of the following is a transcription factor that increases cholesterol synthesis and the expression of LDL receptors?

> a. SCAP Binds to SREBP & INSIG. > **b. SREBP** > c. INSIG Anchors SCAP to ER. > d. OMPLA

**4. Composition of Cells**
4.1 Which of the following represents the abundance of molecules in the body by number?

> a. Water 98%, Simple Inorganic Molecules (NA+, K+, CL-) 2%, Everything else (carbohydrates, proteins, nucleic acids, lipids, etc) 0.2% > b. Water 99%, Simple Inorganic Molecules (NA+, K+, CL-) 0.5%, Everything else (carbohydrates, proteins, nucleic acids, lipids, etc) 0.5% > **c. Water 99%, Simple Inorganic Molecules (NA+, K+, CL-) 1%, Everything else (carbohydrates, proteins, nucleic acids, lipids, etc) 0.2%** > d. Water 90%, Simple Inorganic Molecules (NA+, K+, CL-) 10%, Everything else (carbohydrates, proteins, nucleic acids, lipids, etc) 0.2%

4.2 Which of the following is true?

> a. Sodium is more concentrated in the ICF than the ECF > **b. Potassium is more concentrated in the ICF than the ECF** > c. Big anions are more concentrated in the EFC than the ICF > d. Water is more concentrated in the ICF than the ECF

4.3 Chloride and Bicarbonate are more concentrated in the ECF than the ICF for what main reason?

> a. The plasma membrane is impermeable to Cl- and HCO3- ions. > **b. The inside of the cell is primarily negative in charge.** This also keeps the concentration of K+ higher in the ICF > c. The presence of calcium ions in the cell repels them. > d. The cell actively pumps them out. The cell does, however, actively pump out Na+, which is mildly permeant.

4.4 Which of the following is true?

> a. Primary active transport depends on Na+ molecules leaking into the cell. Primary transport uses ATP. Secondary transport uses anything but ATP and, at times, uses Na+ leaking into the cell as an energy source. > b. Secondary active transport depends on ATP to move molecules across the plasma membrane. See answer "a." > c. Transporters are thousands of times faster than channels. They are thousands of times slower. > **d. Transporters are used to move ions against an energy gradient.** Channels are used to move molecules with an energy gradient and thus do not need to move or need an energy source like ATP.

**5. Cell Volume Regulation**
5.1 Rapid administration of insulin to a patient whose blood glucose concentration is very high can result in which of the following:

> a. Clysis This is when fluids are given sub cutaneously in order to reverse dehydration. This can initially result in the injection site swelling and (dangerously) pulling fluids away from the dehydrated patient before the bubble is broken down. > **b. Cerebral edema** A concentration gradient is created when glucose is absorbed in the body and not in the brain (see answer "d"). The higher concentration of glucose in the brain causes water to infiltrate out of the capillaries and into the ECF of the brain and cause cerebral edema. This can be rapidly reversed with mannitol (a non-permeating sugar). > c. A safe return to homeostatic levels of blood glucose levels > d. A change in the reflection coefficient of brain cells The brain is not dependent on insulin to cause cells to take up glucose.

5.2 Which of the following is not one of the 3 methods used by cells in nature to keep from swelling and bursting?

> a. Rigid cell walls Plant, fungal, & bacterial cells. > **b. Water pumps** > c. Maintenance of solute concentration on both sides of the plasma membrane Most animal cells. > d. Impermeability to water Certain kidney cells.

5.3 What is the difference between osmosis and diffusion?

> **a. Osmosis refers to the diffusion of water.** > b. Osmosis refers to the presence of a semi-permeable membrane. > c. Osmosis is the movement of solvent into a cell and diffusion refers to movement out of a cell > d. Diffusion only refers to a certain class of charged particles

5.4 What do the terms π and ΔC refer to in the equation "π = σRTΔC"?

> a. Reflection coefficient and difference in solute concentration σ is the reflection coefficient. > b. Tonicity and difference in solute concentration > c. Reflection coefficient and change in osmotic pressure > **d. Osmotic pressure and change in solute concentration**

5.5 Which of the following is false?

> a. Osmolarity refers to the difference in solute concentration inside and outside of a cell, regardless of what is permeable to the membrane. > b. The reflection coefficient refers to the effects caused by the rate of solute diffusion across the cell membrane. > c. Tonicity refers to the relative solute concentrations inside and outside of the cell, while taking into account the permeability of solutes. > **d. In a cell that is 300 mOsm for protein, an environment that is 300 mM NaCl is isotonic.** A 300 mM solution of NaCl will disassociate to a 300 mOsm solution of Na+ and 300 mosM solution of Cl-, resulting in a solution that is 600 mOsm for solute (Na+ & Ca-).

5.6 Any solution that makes a cell shrink is:

> a. Hyperosmotic You must determine tonicity to make this call. > b. Hypoosmotic You must determine tonicity to make this call. > c. Hypotonic This would make a cell swell. > **d. Hypertonic**

**6. Membrane Potential I, II, & III**
6.1 The Donnan rule states:

> a. E = 60/z * log(X_outside/X_inside) This is the Nernst equation. > **b. [K_inside][Cl_inside] = [K_outside][Cl_outside]** > c. Bulk solutions are neutral. > d. I before E, except after C, except in "neighbor" and "weigh."

6.2 What is the **primary reason** __for the high concentration of K+ and low concentration of Na+ in the IFC?__

> a. The Na+/K+ pump maintains these concentrations > b. The relative electron affinity of K+ and Na+ > **c. The difference in cell membrane permeability for these two ions** This is responsible for the membrane potential of the cell. > d. The net negative charge inside of the cell has a greater attraction to K+ than Na+

6.3 Why is it possible that the Na+ concentration inside of a cell may be very low (compared to K+) even though the driving force is very high?

> a. Na+ is repelled by the presence of K+ inside of the cell. > b. The concentration of Na+ inside and outside of the cell are almost equal and any slight fluctuation makes a large different in the electrochemical gradient. This is true of the ability of a slight negative charge inside of the cell being able to counteract the osmotic pressure of Cl- ions in the ECF. So much so, that the number of excess negative ions in the ICF has no impact on equations dealing with concentrations. > **c. The relative permeability of sodium is much lower than that of potassium.** V m = (E K + G R * E Na )/(G R + 1). Note that G R is the relative permeability. > d. The dissociation constant of NaCl is too low to allow enough Na+ to get into the cell

6.4 The ECF concentration of Na+ is 100 and the ICF concentration of Na+ is 1. What is E Na ?

> a. It is impossible to tell without knowing the K+ concentrations. > b. 60 mV > **c. 120 mV** Use the Nernst Equation: E = 60/z * log([Xo]/[Xi]) > d. E Na is always +70 mV.

6.5 If E Cl- =-80 mV and V m =-70 mV, is there a Cl- pump? And, if there is, which way is it pumping?

> a. There is no pump. > **b. There is a pump and it is pumping Cl- out** Because E Cl- is not equal to V m, there must be a pump. Because the cell needs to be more positive (-70) than than E Cl- (-80) and because Cl- is negative, Cl- must be pumped out. > c. There is a pump and it is pumping Cl- in > d. What?

6.6 A large drop in extra-cellular Na+ concentration has what consequences to the Vm?

> a. The cell membrane will rapidly depolarize. > **b. The Vm will ever-so-slightly approach E K+ ** > c. The Vm will ever-so-slightly approach E Na+ > d. The Vm will rapidly increase due to the un-matched Cl- ions that now reside outside of the cell membrane Bulk solutions are always neutral. So, where the Na+ goes, so does the Cl-

6.7 You are given concentrations of Na+ & K+ in the ICF and ECF as well as the relative permeability of the two ions. How do you find the membrane potential?

> a. Nernst equation E x =60/z * log([Xo]/[Xi]) > b. Donnan relationship [K i ][Cl i ] = [K o ][Cl o ] > **c. Goldman equation** Vm = 60 log(([K o ] + P r *[Na o ])/([K i ] + P r *[Na i ])) > d. Henderson-Hasselbalch equation

**7. Acids, Bases, & Buffers**
7.1 If (at equilibrium) K eq =.222, k f =2, [A]=3M, [B]=3M, and [C]=2M, what is [D] where A + B -> C + D?

> **a. 1** If K eq =k f /k r, you get .222=(2/k r ), giving k r =9. Then, if you have k f /k r =[C][D]/[A][B], you get (2)/(9) = (2 * [D])/(3 * 3), which makes [D] = 1. > b. 2 > c. 3 > d. 4

7.2 If [OH-] is 10 -5, what is the pH?

> a. 1 > b. 3 > **c. 9** Since [H+][OH-] = 10 -14, then you get [H+]*10 -5 = 10 -14. So [H+]**= 10 -9 **. The pH is the negative log of 10 -9, which is 9. > d. 5

7.3 Which of the following are the clinical pH values in ECF for acidosis and alkalosis, respectively?

> a. 7.3 pH & 7.5 pH > b. 7 pH & 8 pH > c. 7.39 pH & 7.41 pH > **d. 7.35 pH & 7.45 pH**

7.4 An acid is left to reach equilibrium in in water. The resulting concentrations are: [H+] = 3 mM, [A-] = 3 mM, and [HA] = 25 mM. What is pKa?

> **a. 0.44** pKa=-log([H+][A-]/[HA]) -- pKa=-log(3*3/25) = 0.44 > b. 0.48 > c. 9 > d. 175

7.5 Which of the following is the correct form of the Henderson-Hasselbalch equation?

> **a. pH = pKa + log([A-]/[HA])** > b. pH = pKa - log([A-]/[HA]) > c. pKa = pH + log([A-]/[HA]) > d. pKa = pH * log([A-]/[HA])

7.6 If the solution in which an acid resides is at a pH below the pKa of that acid, which of the following is true?

> **a. The acid will primarily not be disassociated (intact, e.g. HA).** > b. The acid will primarily be disassociated (e.g. H+ & A-). > c. You can tell nothing about the association of the acid based on this relationship. > d. None of the above.

7.7 Which of the following is the correct form of the Henderson-Hasselbalch equation as it applies to CO2/Bicarb buffering?

> a. pH = 6.3 + log [HCO 3 - ]mM/ .01P co 2 mmHg > **b. pH = 6.1 + log [HCO** **3** **-** **]mM/ .03P** **co** **2** **mmHg** > c. pH = 6.3 + log [HCO 3 - ]mM/ .03P co 2 mmHg > d. pH = 6.1 + log [HCO 3 - ]mM/ .01P co 2 mmHg

7.8 Which of the following is incorrect?

> a. Normal arterial blood pH: 7.34-7.44 > **b. Normal venous blood pH: 7.38-7.52** Venous blood is more acidic than arterial blood due to higher CO2 content. > c. Normal concentration of HCO3- in blood: 24 mM > d. Normal PCO2 in blood: 40 mm Hg > e. Normal concentration of CO2 in blood: 1.2 mM

7.9 Which is the best guestimate of a buffering range of a buffer?

> a. 0.001 mM. > **b. +/- 1 pH around the pKa of the buffer.** > c. The inverse of the pKa. > d. This number varies based on the current position of the titration curve.

7.10 Which of the following amino acids has a side chain that can protonate/deprotonate at physiological pHs?

> a. Lysine This AA is one of the three basic AAs. > b. Serine This AA is one of the three AAs with a conveniently placed -OH > c. Cysteine This AA is one of two containing sulfur. This AA forms disulfide bonds. > **d. Histidine**

**8. Membrane Fusion 9. Membrane Transporters**
8.1 Which of the following is not a SNARE protein?

> a. Syntaxin > b. SNAP-25 > c. VAMP > **d. β-catenin** A SNARE protein facilitates membrane fusion. β-catenin is a transcription up-regulator that may result in a neoplasm if not controlled by APC.

8.2 All target membranes contain which two SNARE proteins?

> a. Syntaxin & VAMP VAMP is only present on vesicles. > b. VAMP & SNAP-25 VAMP is only present on vesicles. > **c. Syntaxin & SNAP-25** > d. VAMP & Sec1 VAMP is only present on vesicles.

8.3 Which of the following is a hexameric protein that disassembles a SNARE complex?

> **a. NSF** NSF disassembles the SNARE complex alongside α-SNAP. > b. syn5 One of the many Syntaxins. > c. TGN Trans-golgi network. Not covered in this unit. > d. n-Sec1 Refolds Syntaxins after a membrane fusion event.

8.4 In order to enter a cell, a enveloped virus uses:

> a. The SNARE complex. > **b. A single viral protein that unfolds and stabs one end of its binding protein into the membrane of the target cell.** > c. A targeted release of H+. Some virii (influenza) need a drop in pH (as found in endosomes) to become active. > d. Diffusion down its concentration gradient.

**9. Membrane Transporters**
9.1 Glucose is trapped inside of a cell by which mechanism?

> a. The negative charge inside of the cell attracts glucose molecules > b. Glucose stays because it is energetically favorable due to the concentration gradient. > **c. Glucose is sequestered as G6P which cannot be transported out by the glucose transporter protein.** > d. Glucose is phagocytized by the cell.

9.2 The Na/K pump is an example of what?

> **a. Primary Active Transport** > b. Secondary Active Transport > c. Passive Diffusion > d. Co-transport Diffusion This is an example of exchange transport.

9.3 Calcium ions in the cytoplasm signal all of the following, except:

> a. Muscle contraction > b. Cellular Excretion > c. Apoptosis > **d. Glucose uptake**

9.4 Which of the following is not an effective treatment for hyperkalemia?

> a. Calcium ion > b. Bicarbonate ion Functions via theoretical H/K pump > c. Insulin + Glucose > d. Kayexelate One of two methods that involve removing K from the body. > e. Dialysis One of two methods that involve removing K from the body. > **f. All of the above are effective treatments This group also includes β-agonists like Albuterol **

**11. MS Vignette**
11.1 MS is diagnosed by:

> a. Lesions disseminated in time. > b. Atleast two lesions in different places in the CNS. > c. Abnormalities in the neurological exam. > **d. All of the above.**

11.2 Which of the following is true?

> **a. MS can cause lesions that can break the blood/brain barrier.** > b. Demyelination can increase amplitude of action potentials. It decreases amplitude and speed of action potentials. > c. Schwan cells myelinate multiple neurons in the CNS. Oligodendrocytes do this. > d. Oligodendrocytes myelinate a single neuron in the PNS. Schwan cells do this.

11.3 Which of the following is true about a CSF analysis in a person with MS?

> a. Protein usually > 110 mg/dL Opposite is true. > b. WBC frequently > 40/mm3 Opposite is true. > c. Abnormal Glucose Opposite is true. > **d. Abnormal presence of immunoglobulins**

**12. Epithelial Transport**
12.1 Which of the following types of epithelia can make use a pericellular shunt pathway?

> a. Epithelia with truly tight junctions > **b. Epithelia with leaky tight junctions** All of the other choices are "tight" tight junctions where solutes must pass through the epithelial cell to reach the interstitial fluid. Leaky tight junctions allow solutes to pass between the epithelia in the pericellular shunt pathway in order to reach the interstitial fluid. > c. Epithelia in sweat glands > d. Epithelia of the distal parts of kidney tubules

12.2 Which of the following are examples of epithelia with "tight" tight junctions?

> a. Epithelia of the small intestine Epithelia engaged in massive transport are almost always leaky. "Tight" tight junctions are used in cases where 'fine tuning' of solute concentrations is necessary, such as in the distal parts of kidney tubules. > b. Epithelia junctions of the large intestine See a. > **c. Epithelia that need to maintain large energy gradients** Leaky tight junctions by their very nature cannot prevent solutes from leaking back through and thus cannot establish a concentration gradient. > d. Epithelia of the gall bladder The gallbladder makes use of leaky tight junctions.

12.3 Nearly all cellular transport is done by:

> a. ATP-driven pumps (primary active transport) > **b. Secondary active transport involving Na+** > c. Endocytosis > d. Pinocytosis

12.4 Which of the following is the main cellular transport mechanism for H+?

> **a. ATP-driven pumps (primary active transport)** Examples: stomach cells secreting H+ into the stomach lumen and kidney cell excreting excess H+. > b. Secondary active transport involving Na+ > c. Endocytosis > d. Gas exchange in the lungs This is the main transport mechanism for O2/CO2. It does not require epithelia because O2 and CO2 can diffuse across the cellular membrane. It uses endothelium.

12.5 The apical solution is _ compared to the basolateral solution?

> a. Positive > b. Neutral > **c. Negative** When sodium enters the epithelial cell, it momentarily leaves behind Cl-. As soon as the charge gradient is established by sodium entering the cell, the Cl- follows along. > d. Can be any charge

12.6 Voltage potentials are written:

> **a. As the potential of the inside of the cell with respect to the oustide.** > b. As the potential of the outside of the cell with respect to the inside. > c. Without respect to the inside or outside of the cell (it ends up being the same mathematically). > d. All of this voltage potential stuff is made up without rhyme or reason.

12.7 Which of the following is not a method in which ions are absorbed into the interstitial fluid from the lumen?

> a. Apical Na+ and Cl- channels, Basilar Na+/K+ pump and Cl- channels > b. Apical Na+ channels, pericellular Cl- shunt, basilar Na+/K+ pump > c. Na/K/2Cl apical cotransporter, Basilar Na+/K+ pump and Cl- channels > **d. Apical charge mediated pinocytosis, Basilar Na+/K+ pump and Cl- channels**

12.8 The major cellular defect in cholera is:

> a. Overproduction of acetyl choline. > **b. Overproduction of cAMP.** The cholera toxin causes in increase in production of cAMP. cAmp opens apical Cl- channels ( **CFTR** ). The Cl- leaks into the lumen, making it negative. Na+ follows the negative charge through the leaky junction (shunt) and into the lumen. H2O follows the Na+. > c. A defective apical Na/K pump. > d. A defective apical Cl- channel.

12.9 Which of the following is false?

> a. In epithelia, sugar and amino acids cannot enter the cell if they are not accompanied by Na+. > b. In epithelia, the movement of Na+ into the cell is reduced if no extracellular sugar of amino acids are present. > **c. The transport mechanism of glucose in epithelial cells and in muscle cells is similar.** Muscle cells use facilitated diffusion whereas epithelia use secondary active transport. > d. The kidney and the GI tract absorb amino acids and glucose in a similar fashion. > e. In epithelial cells, apical membrane proteins may not freely diffuse to the basolateral membrane. The tight junctions prevent this kind of movement.

12.10 What will happen if you eat a bunch of glucose without any NaCl?

> a. You will not be able to absorb the glucose. > b. You will absorb the glucose in the absence of NaCl by using analogous ions. > **c. NaCl leak into the lumen through leaky (shunt) junctions so that you may absorb the glucose.** > d. NaCl diffuse out of the cell and into the lumen so that you may absorb the glucose.

12.11 How do epithelial cells regulate how much of a nutrient they absorb?

> a. By closing Na+ channels. > b. By closing nutrient specific channels. > c. By using an ATP-driven mechanism to pump the nutrients back into the lumen. > **d. They don't.**

12.12 What will happen if you eat a bunch of L-glucose?

> a. The same thing as eating R-glucose. > b. It will damage your kidneys during excretion. > d. The epithelial cells will convert the L-glucose into R-glucose.
 * c. It will cause diarrhea by drawing water into the lumen. ** You will be unable to absorb the L-glucose molecule and this will create an osmotic pressure that will draw water molecules into the lumen. **

12.13 Water always moves passively into cells, which of the following epithelial cells is impermeable to water?

> a. GI tract epithelium > b. Sweat gland epithelium ** This is also true for some parts of the kidney tubules, especially in response to vasopressin. ** > c. Muscle cells > d. None of the above

12.14 How much of the total metabolic waste a person makes in a day (15 moles) is composed of H+?

> a. Almost all of it (14.5 M). This is the amount of CO2 waste. Approx. 1L of water goes with this CO2 waste. > b. Little of it (.450 M). This is the amount of waste that becomes urea (the end product of nitrogenous waste). > c. Very little of it (.050 M). > d. The body does not get rid of H+ ions because they are used in mitochondria.

12.15 The kidney functions by:

> a. Pumping urea and other wastes out of the blood. > b. Passively diffusing urea and other wastes out of the blood. > c. Pumping blood through a filter at pressure to get an ultrafiltrate of good stuff and bad stuff. ** The kidney then reabsorbs what it likes out of the filtrate. ** > d. Pumping K+ out of the blood plasma and letting the urea follow.

12.16 Which of the following is not true of the GI tract?

> a. The GI tract excretes about 30 mM of metabolic waste per day. Most of this is RBC breakdown products. > b. The GI tract is very specific about the molecules it absorbs. Will not absorb things like L-glucose. > c. The GI tract breaks down the normally harmless butulinum toxin into a poisonous micro-protein before absorbing it. ** The large BT protein is absorbed whole by the GI tract. ** > d. The GI tract excretes highly toxic RBC breakdown products.

12.17 CFTR is:

> a. A regulator of the Cl- channel that is broken in people with CF. CFTR is a Cl- channel that is opened by cAMP and Ca. > **b. Cl- channel that is broken in people with CF.** Because the cell cannot pump Cl- into the lumen, Na+ will not follow and H2O will not follow the Na+. Thus, the mucous in the lumen is extra thick, which makes the patient vulnerable to infection. > c. A transcription factor of a gene that codes for a protein in the Cl- channel. > d. A malfunction in the Na/2Cl/K pump on the basolateral surface of epithelial cells.

13. Action Potential I, II, & III
13.1 As an action potential reaches the terminal end of the pre-synaptic neuron, ions channels open and let which substance into the cytoplasm in order to cause the fusion of excretory vesicles to the cell membrane (so that they can release their contents into the synaptic cleft)?

> a. Glutamate This is the most abundant neurotransmitter in the body. This substance is leaked into the synaptic cleft in response to an increase in pre-synaptic intracellular calcium ions. One in the cleft, this molecule causes the sodium gates on the post-synaptic neuron to swing open, causing an action potential. > b. Sodium > **c. Calcium** > d. Potassium

13.2 What keeps an action potential from withering away during conduction down a neuron?

> a. Accommodation Accommodation is when a cell loses sensitivity to a slow depolarization. > **b. Voltage-gated sodium channels** > c. The absolute refractory period This is the minimum amount of time necessary for a neuron to fire again. The relative refractory period is the time in which a nerve will fire even though it is not fully rested given a strong enough depolarization. > d. Open ion channels Open ion channels contribute to the degradation of action potential.

13.3 What is the ratio of Na current to K current at threshold?

> a. 75:25 > **b. 50:50** This is the definition of threshold. > c. 25:75 > d. Irrelevant

13.4 In general, compared to large axons, small axons:

> a. Are capable of firing more between rest periods. The converse is true. > **b. Are more resistant to external stimulation.** > c. Have a faster action potential The converse is true. The smallest fibers tend not to be myelinated, as well. > d. Are more difficult to block with anasthetic (m gates more difficult to block). The converse is true. > e. Accommodate more slowly. The converse is true.

13.5 Which of the following is considered a large nerve fiber?

> a. A pain fiber. Because pain fibers are smaller, they may not be excited when a current is applied externally to test the conduction of a larger nerve fiber. > b. A temperature fiber. > **c. A touch fiber.** > d. None of the above.

13.5 A myelinated fiber conducts faster because myelin:

> a. increases capacitance and decreases resistance of nerve fibers membranes. > b. decreases capacitance and decreases resistance of nerve fibers membranes. > **c. decreases capacitance and increases resistance of nerve fibers membranes.** > d. increases capacitance and increases resistance of nerve fibers membranes.

14. DKA Vignette
14.1 Which of the following is not a step in insulin release?

> a. Glucose is brought into the ß-cell via a passive carrier. > **b. Intracellular K is exchanged with extracellular H+** > c. Cell depolarization causes Ca voltage-gated channels to swing open > d. An increase in cellular ATP to ADP ratio causes inhibition of a K channel.

14.2 Which of the following is true of DKA?

> a. Mannitol can be used to remove excess K from the blood. Mannitol increases capillary osmolarity to prevent cerebral edema. > **b. Starving cells make use of lipolysis for fuel which creates ketone bodies.** > c. Cerebral edema is more often seen as a complication of DKA in adults than in children. The converse is true. > d. During episodes of DKA, total body potassium levels are high. Although serum K is normal or high, total body K is low because K is being excreted due to polyuria.

14.3 Which of the following is not frequently a symptom of DKA?

> a. Kussmaul respirations > b. Altered conciousness > **c. Peak T-waves on ECG** This is a feature of hyperkalemia. > d. Polyuria > e. Nausea

15. Secretory Pathways I & II
15.1 Signal recognition proteins have an abundance of which amino acid at its signal sequence binding pocket?

> a. Arginine > b. Mescaline > c. Cysteine > **d. Methionine** Remember that methionine is flexible in recognizing sequences.

15.2 How is Rough ER protein synthesis regulated?

> a. It is not. > b. It is regulated by the ribosome on the cytoplasmic side > c. It is regulated by a chaperonin on the lumenal side > **d. It is regulated by both a chaperonin and the ribosome**

15.3 Which end (on either side of the transmembrane domain) of the nascent protein will stick into the ER lumen in a type II protein?

> a. The side with a positively charged patch > b. The N-terminal end > **c. The C-terminal end** The ribosome builds on the COO- end > d. None of the above

15.4 In the Rough ER/Golgi, which of the following amino acids is involved with N-linked glycosylation? Which are O-linked?

> a. Alanine; Cysteine, Methionine > b. Asparagine; Serine, Tryptophan > **c. Asparagine; Serine, Threonine** > d. Arginine; Serine, Histidine

15.5 Which of the following sequences must be present in order for a protein to be glycosylated with the core glycosylation during post-translational modification in the rough ER?

> a. asn-something-ser-thr > **b. asn-something-ser/thr** > c. asn-something-ser-something-thr > d. asn-ser-something-thr

15.6 A protein that is linked to a rough ER membrane by a GPI anchor will eventually end up where?

> **a. On the outer leaflet of the plasma membrane** > b. On the inner leaflet of the plasma membrane > c. In the cytosol > d. On the nuclear envelop

15.7 Which of the following is not a secretory pathway for proteins in a cell?

> a. Using a receptor protein to carry another protein from the cytosol into the membrane through a pore complex. > b. Using a translocon to move a protein across a membrane. > c. Using a membrane, adaptor proteins, and coat proteins to form vesicles that carry the contents to different cellular location. > **d. All of the above are secretory pathways for proteins in a cell.**

15.8 Which of the following is not a function of the ER.

> a. Lipid synthesis > b. Placement of disulfide bonds onto proteins > c. Cholesterol homeostasis > **d. Synthesis of complex sphingolipids from a ceramide backbone** This is a major function of the golgi

15.9 Which of the following is false?

> a. Proteins are left in the cytosol or directed to the ER based on specific 5' sequences > **b. Co-translational translocation is the process of moving a maturing protein from the cis-golgi to the trans-golgi** Co-translational translocation is when a nascent protein is translated into the lumen of the ER through a translocon. > c. Protein cleavage is a major function of the golgi complex > d. Transmembrane proteins can be sorted into transport vesicles based on vesicle thickness.

15.10 Which of the following molecules provides the energy to make clathrin-coated vesicles naked?

> a. ATP > **b. GTP** GTPases provide energy to form, secrete, and fuse vesicle membranes. > c. NADH > d. FADH

15.11 Dynamin is:

> a. A cargo receptor > b. An adaptor between a cargo receptor and a clathrin molecule > c. A type of clathrin molecule > **d. A 'pinchase' that pinches a vesicle off of a membrane**

15.12 Which one of the following coats is responsible for retrograde movement of proteins in the ER/Golgi?

> a. Clathrin Endocytosis and transport between lysosomes and the golgi > **b. COPI** > c. COPII From ER to golgi > d. None of the above

16. Cholera Vignette
16.1 The current (7th) cholera pandemic is caused by which strain of Cholera?

> a. Classical (O1) > **b. El Tor (O1)** > c. Bengal (O139) > d. O1N1

16.2 Which of the following is not a symptom of cholera?

> a. Grey, cloudy stool > **b. Mid-epigastric pain** > c. Vomiting > d. Severe, rapid dehydration

16.3 Cholera is spread via:

> a. Airborne droplets > b. Direct person-to-person contact > c. Saliva > **d. Fecal-oral route**

16.4 Approximately, how many Vibrio Cholerae bacteria must one ingest to become infected?

> a. 10 True of Shigella > b. 100,000 True of Salmonella > c. 1,000,000 > **d. 100,000,000** This means you must have a significant intake of the bacteria to become infected.

16.5 In cholera toxin, which of the following is true?

> a. Both A and B subunits are toxic. > b. The A subunit is a transport molecule and the B subunit contains the toxic active site > **c. The B subunit is a transport molecule and the A subunit contains the toxic active site** > d. None of the above

16.6 Which ion or molecule over-activates the CTFR channel in cholera?

> a. GM1 ganglioside This is the membrane molecule that the B subunit binds to > b. Ca > **c. cAMP** > d. Cholera toxin directly attacks CTFR itself

16.7 Cholera causes which type of diarrhea?

> **a. Secretory** > b. Osmotic This type of diarrhea is caused when the lumen contents are of higher osmolarity than the EFC > c. Lumenal This is not one of the two types of diarrhea discussed. > d. None of the above

16.8 In an oral rehydration solution, if you had 10 mEq of Na, how much glucose would you want?

> a. 1 mmol > **b. 10 mmol** WHO recommends a Na to glucose prorpotion of 1:1-1.4 > c. 50 mmol > d. 100 mmol

17. Nucleus & Nuclear Import/Export
17.1 Which of the following sets of amino acids are found in the nuclear pore and help with the import and export of large molecules?

> a. Proline and Glycine > **b. Phenylalanine and Glycine** > c. Proline and Glutamine > d. Phenylalanine and Glutamine

17.2 Proteins destined for which of the following locations are folded before they arrive?

> **a. Proteins destined for the nucleus** All other proteins are left unfolded prior to reaching their destiation. > b. Proteins destined for the Rough ER > c. Proteins destined for a peroxisome > d. Proteins destined for a mitochondria

17.3 Which of the following is true?

> a. The nuclear pore complex is approximately the same size as a ribosome It's about 30x larger. > b. Molecules smaller than 50,000 daltons may freely diffuse into the nucleus True of molecules <5,000 daltons > c. A string of negative amino acids or a negative amino acid patch signal a protein for nuclear import This is true of positive amino acids > **d. The nuclear pore complex functions to keep inner membrane proteins on the inner membrane and outer membrane proteins on the outer membrane of the nucleus.**

17.4 Ran-GDP is:

> a. Exported from the nucleus down its concentration gradient. > **b. Formed by using GAP to hydrolyze GTP in the cytosol.** > c. Used alongside an exportin in order to remove cargo from the nucleus. > d. Used to export mRNAs from the nucleus. mRNAs used mRNA exporters to traverse nuclear pores.

17.5 Ribosomes are:

> a. Primarily assembled in the cytoplasm. > **b. Made with proteins assembled in the cytoplasm.** > c. Exported from the nucleus without the use of nuclear pores > d. None of the above.

18. Protein Degradation
18.1 HSP70:

> a. Is only found in the cytoplasm and in the nucleus. This is true of the HSP60 family > b. Binds ATP in order to bind a "cap" protein. This is true of the HSP60 family > c. Binds specifically to hydrophilic patches of proteins Binds to hydrophobic patches > **d. Releases from its bound protein when it hydrolyzes ATP.**

18.2 Which of the following is true?

> a. 80% of all proteins fold correctly without help from a chaperonin. Something like 40% > **b. 30% of all proteins are folded with assistance from chaperonins like hsp60 and hsp70** > c. 60% of proteins are misfolded and subsequently digested by a proteosome. 30% > d. None of the above.

18.3 Retrotranslocation is the process of:

> a. Multiubiquitinating proteins to target them for digestion in a lysosome. > **b. Sending a mis-folded protein back through a translocon and into a cytoplasmic proteosome.** > c. Adding lysine to the N-terminal end of a protein which does not contain a lysine residue in order to attach a ubiquitine to that protein. > d. Bringing the contents of a clathrin coated vesicle into contact with a lysosome.

18.4 UDP-Glc (a glucosyl transferase) does which of the following:

> a. Actives ubiquitine. This is true of the E1 enzyme > b. Transfers active ubiquitine to another enzyme which then places the ubiquitine on the lysine of the protein to be degraded. This is true of the E2 enzyme > c. Removes glycosylations from mis-folded proteins in the cytosol. This is true of N-glycanase > **d. Continually transfers a sugar onto a misfolded protein to prevent that protein from exiting the ER via a COPII vesicle.**

18.5 Proteosomes:

> a. Use ATP during cleavage reactions that are performed on unfolded proteins. Proteosomes use ATP to unfold and translocate proteins > b. Are found in the cytosol, nucleus, and rough ER. They are not found in the rough ER, hence the necessity for retrotranslocation. > **c. Have a caspase-like ß-1 subunit that cleaves after acidic amino acids** > d. Have α subunits that regulate entry of proteins into the "death chamber" by binding hydrophilic regions of the protein being digested. The α subunits bind hydrophobic patches.

18.6 Which of the following enzymes is responsible for transferring an activated ubiquitin to a protein in order to target it for degradation?

> a. E1 > b. E2 > **c. E3** > d. Lys-48 This is the lysine (#48) that is used for polyubiquitination. In other words, ubiquitin is ubiquitinated at this site.

18.7 Which of the following are capable of breaking down large molecules (e.g. LDL) into basic cellular "building blocks?"

> a. Caveolae > **b. Lysosomes** > c. Early Endosomes > d. Autophages Do not exist. Lysosomes are used for autophagy.

19. Hyperkalemia Vignette
19.1 Which of the following is not a cause of hyperkalemia?

> a. ACE inhibitors Inhibits aldosterone which holds onto H2O and Na while shedding K. > b. Rhabdomyolysis > c. DKA High acidity in the blood can cause cells to exchange K (out) for H+ (in). > **d. Diarrhea** This and sweating can cause a loss of K, possibly leading to hypokalemia.

19.2 Which of the following is not a symptom of hyperkalemia?

> **a. Headache** > b. Weakness/Paralysis > c. Abnormal hearth rhythm > d. Nausea

19.3 Which of the following foods is low in K?

> a. Potatoes > b. Tomatoes > c. Avocados > **d. Apples**

20. Cytoskeleton I & II
20.1 A "9 + 2 array" describes the molecular structure of which cytoskeletal element?

> a. A microtubule > b. A microfilament > c. An intermediate filament > **d. None of the above** 9 + 2 describes the arrangement of microtubules in an axoneme, the core component of cilia and flagella.

20.2 Which of the following cytoskeletal elements is primarily responsible for cellular movement?

> a. Microtubules Cilia, flagella, scaffolding, and movement of organelles > **b. Microfilaments** > c. Intermediate filaments Mechanical stability > d. None of the above

20.3 Which of the following proteins help to move the cargo of the Herpes Simplex virus toward the minus end of a microtubule in order to reach the cell nucleus?

> a. Kinesins Moves toward the plus end of MTs > **b. Dyneins** > c. Myosin Moves toward the plus end of microfilaments > d. Fimbrin Cross links microfilaments together in villi along with villin

20.4 GTP favors growth of which of the following:

> **a. Microtubules** > b. Microfilaments ATP favors growth for microfilaments > c. Intermediate filaments > d. Actin tetramers

20.5 Intermediate filaments are approximately how large in diameter?

> a. 25 nm (13 protofilaments) MTs > b. 5-9 nm (double helix) MFs > **c. 10 nm (32 helical coils)** > d. 1 nm (monofilament)

20.6 Epidermolysis bullosa symplex, a disease in which the skin is highly sensitive to mechanical stress and blisters easily, is due to a mutation in which of the following?

> a. Beta tubulin > b. Actin > **c. Keratin** > d. GFAP Mutations in GFAP can result in Alexander's disease. A fatal disease that has to do with myelination.

20.7 Kartagener syndrome is frequently characterized by:

> a. Peripheral neuropathy A cytoskeletal disorder matching this may be Charcot-Marie-Tooth > b. Thrombocytopenia A cytoskeletal disorder matching this may be Wiskott-Aldrich syndrome (WAS) > c. Absence of gyri in the brain A cytoskeletal disorder matching this may be Lissencephaly > **d. Situs inversus**

20.8 Which of the following binds to and stabilizes microtubules?

> a. Colchicine Interfere with polymerization at the plus end > b. Vinblastine Interfere with polymerization at the plus end > **c. Paclitaxel** Cancer treatment that stops mitosis by over-stabilizing microtubules. > d. Lysergic acid diethylamide Hallucinogenic substance popular in the 60s. More commonly known as LSD.

20.9 Which of the following polymerize the minus end of an actin strand?

> a. Rho proteins Causes formation of stress fibers. > **b. ARP proteins** > c. Rac Causes formation of veils. > d. Cdc42 Causes protrusion of filopodia.

21. Cell Signaling (Overview I & II)
21.1 Which of the following methods of cell signaling do NOT require production of secreted protein?

> **a. Contact-dependent** > b. Paracrine > c. Endocrine > d. Synaptic

21.2 Calcium is an example of a: > a. node and a primary messenger > **b. node and a secondary messenger** > c. module and a primary messenger > d. module and a secondary messenger > e. None of the above

21.3 Phospholipase C (PLC) cleaves phosphatidyl inositol-bisphosphate (PIP2) to form two secondary messengers: > a. cytosolic inositol triphosphate (IP3) and cytosolic diacylglycerol (DAG) > **b. cytosolic IP3 and membrane-bound DAG** > c. membrane-bound IP3 and cytosolic DAG > d. membrane-bound IP3 and membrane-bound DAG

26. Receptor Tyrosine Kinases
26.1 Which of the following are required for receptor tyrosine kinase activation?

> a. Dimerization > b. Ligand binding > c. Autophosphorylation > **d. All of the above** > e. (a) and (b)

26.2 The SH2 domain of Grb2 binds to:

> **a. Phosphorylated tyrosine residues on the receptor tyrosine kinase** > b. Phosphorylated tyrosine residues on the guanosine nucleotide exchange factor Sos These don't exist > c. Proline-rich sequence on the receptor tyrosine kinase These don't exist > d. Proline-rich sequence on the guanosine nucleotide exchange factor Sos The SH3 domain of Grb2 binds to this

26.3 The SH3 domain of Grb2 binds to:

> a. Phosphorylated tyrosine residues on the receptor tyrosine kinase > b. Phosphorylated tyrosine residues on the guanosine nucleotide exchange factor Sos > c. Proline-rich sequence on the receptor tyrosine kinase > **d. Proline-rich sequence on the guanosine nucleotide exchange factor Sos** See above, #26.2

26.4 The function of Sos is to:

> a. Phosphorylate Ras > **b. Activate Ras by attaching a GTP molecule** Sos is a guanosine nucleotide exchange factor, which by definition activates its target protein by switching out a GDP for a GTP > c. Inactivate Ras by hydrolyzing a GTP molecule > d. Bind to the SH3 domain of Grb2 Distracter. Sos does bind to the SH3 domain of Grb2, but this is its method of activation, not its function

26.5 Grb2 that is artificially targeted to the plasma membrane will result in consitutive activation of Raf in the absence of receptor tyrosine kinases.

> a. True > **b. False** Grb2 only matters insofar as it binds to Sos and positions it near the plasma membrane to act on Raf. Thus, artificially targeting Sos to the plasma membrane will result in constitutive activation of Raf in the absence of receptor tyrosine kinases.

26.6 Which method is LEAST likely to determine likely outcome of Gefitinib treatment for lung cancer? > a. DNA sequencing > b. Fluorescence in situ hybridization > **c. Karyotyping** Lung cancer is not caused by gross chromosomal abnormalities. All the other answer choices can determine if there is a mutation of the EGFR gene or if EGFR is overexpressed. > d. Immunohistochemistry

26.7 Smoking confers primary resistance to Gefitinib treatment for lung cancer because: > a. Cigarette smoke induces a conformational change in EGFR that prevents it from binding to Gefitinib > b. Cigarette smoke induces a conformational change in Gefitinib that prevents it from binding to EGFR > c. The carcinogens in tobacco smoke cause mutations in EGFR that prevents it from binding to Gefitinib > **d. The carcinogens in tobacco smoke cause mutations in Ras, a gene downstream from EGFR** Gefitinib is a tyrosine kinase inhibitor that reduces EGFR overexpression or overactivity. Thus, if the primary mutation caused by tobacco smoke is downstream from EGFR, Gefitinib will not have an effect.