M2M+Unit+II+Practice+Questions


 * //The following are student-developed test questions taken from the Learning Objectives.// **

=****Questions**** (answers at bottom of page)****:****=

__1. Pedigree and Mendelian Inheritance__
1.1. In a pedigree, a male with a positive phenotype is depiced as:

a) a black square b) a white circle c) a square with a line through it d) a black diamond

1.2. The father in a family has an x-linked recessive disease. He has four childen: two boys and two girls. Which of the following is true:

a) Both of the girls are carriers and both boys will have the disease. b) Neither of the girls are carriers and both boys will have the disease. c) Both of the girls are carriers and neither of the boys will have the disease. d) It is impossible to tell who will be a carrier and who will have the disease.

1.3. Two parents are phenotypically normal but one of their daughters exhibits a disease phenotype. Which of the following is true:

a) The faulty gene is dominant. b) The faulty gene is recessive. c) The faulty gene is x-linked recessive. d) It is impossible to establish the dominance/recessiveness based on this information.

1.4. The percent of individuals in a population with a recessive phenotype is 3.5%. What is the percentage of individuals that are heterozygous?

a) 30.4% b) 66.1% c) 3.5% d) 18.7% e) This is impossible to solve without using a quadratic equation.

1.5. If you only have a single functional copy of a gene and you are unable to produce enough of a protein, you are:

a) Haploinsufficient b) Submetacentric c) Hemizygous d) Heterochromatic

1.6. When vegans have a B12 deficiency and their phenotype appears to be similar to those with genetic homocystinuria, this is an example of:

a) A modifier gene b) A stocastic event c) Expressivity d) A phenocopy

1.7. A mutation in a single gene can cause several different phenotypic traits is an example of what?

a) Penetrance b) Expressivity c) Polyploidy d) Pleiotropy

1.8. Which of the following does not mess up the results of a calculation done using Hardy-Weinberg principle?

a. Random mating b. Non-random mating c. Small Population Size d. Medicinal Palliative Effects

1.9. If there are 3 new cases of an autosomal dominant disease (with no family history) in 300 live births what is the mutation rate (µ)?

a) .005 b) .01 c) 1 in 300 d) 1 in 150

__2. Genome organization__
2.1. Which of the following histone subunits is not a part of the nucleosome?

a) H1 b) H2A c) H2B d) H3 e) H4

__23. Bench-to-Bedside: Gaucher__
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=****Answers:****=

__1. Pedigree and Mendelian Inheritance__
1.1) In a pedigree, a male with a positive phenotype is depiced as: ** a) a black square** b) a white circle This is the symbol for an unaffected female. c) a square with a line through it This is a deceased male. d) a black diamond This is a positive phenotype of unknown gender.

1.2. The father in a family has an x-linked recessive disease. He has four childen: two boys and two girls. Which of the following is true:

a) Both of the girls are carriers and both boys will have the disease. The boys cannot receive an X chromosome from their father. b) Neither of the girls are carriers and both boys will have the disease. The boys cannot receive an X chromosome from their father. The girls must receive an X chromosome from their father. ** c) Both of the girls are carriers and neither of the boys will have the disease. The boys cannot receive an X chromosome from their father. The girls must receive an X chromosome from their father. ** d) It is impossible to tell who will be a carrier and who will have the disease.

1.3. Two parents are phenotypically normal but one of their daughters exhibits a disease phenotype. Which of the following is true:

a) The faulty gene is dominant. If this were the case, the phenotype would be seen in at least one of the parents. ** b) The faulty gene is recessive. ** The fact that neither of the parents has the disease tips you off that it is recessive. The fact that a daughter has it means that it is somatic. c) The faulty gene is x-linked recessive. Daughters do not show the phenotype of an x-linked recessive trait. d) It is impossible to establish the dominance/recessiveness based on this information.

1.4. The percent of individuals in a population with a recessive phenotype is 3.5%. What is the percentage of individuals that are heterozygous?

b) 66.1% c) 3.5% d) 18.7% e) This is impossible to solve without using a quadratic equation.
 * a) 30.4%** In the equation p^2 + 2pq + q^2 = 1, the term q^2 is the percentage of homozygous recessive individuals in a population. Taking the square root of 3.5% (q^2) gives you q, which is .187. Using the equation p + q = 1, you can substitute in q (.187) to give: p + .187 = 1. Which gives a value of .813 for p. You can then substitute your values for p and q back into the first equation: (.813)^2 + 2(.813)(.187) + (.035)^2 = 1. The middle term "2pq" is your percentage of heterozygous individuals. In this case the middle term is 2(.813)(.187), which equals .304 or 30.4%.

1.5. If you only have a single functional copy of a gene and you are unable to produce enough of a protein, you are:

b) Submetacentric This describes a chromosome whose centromere is off-centered. c) Hemizygous This is when a diploid organism only has one copy of a gene. This is true of this question but not the best answer. d) Heterochromatic This describes chromatin that is highly compressed and generally not transcribed (contrast with euchromatin).
 * a) Haploinsufficient** ** Haploinsufficiency ** occurs when a [|diploid] organism only has a single functional copy of a [|gene] (with the other copy inactivated by [|mutation]) and the single functional copy of the [|gene] does not produce enough of a gene product (typically a [|protein]) to bring about a [|wild-type] condition, leading to an abnormal or diseased state. It is responsible for some but not all autosomal dominant disorders.

1.6. When vegans have a B12 deficiency and their phenotype appears to be similar to those with genetic homocystinuria, this is an example of:

a) A modifier gene This is a genetic factor that influences a phenotype generated by another gene b) A stocastic event This is a random event that influences a phenotype c) Expressivity This is the level of severity of a phenotype
 * d) A phenocopy** This is a phenotype caused by non-genetic factors that matches a phenotype caused by genetic factors.

1.7. A mutation in a single gene can cause several different phenotypic traits is an example of what?

a) Penetrance This is a binary situation in which a person either has a disease or does not. b) Expressivity This describes the level to which a phenotype is seen c) Polyploidy This is the situation in which a person has more than two copies of every chromosome (ie 69 XXY). See also tetraploidy, triploidy.
 * d) Pleiotropy** When a mutation leads to multiple different phenotypes. Example (from wikipedia): A classic example of pleiotropy is the human disease PKU ([|phenylketonuria]). This disease can cause [|mental retardation] and reduced [|hair] and [|skin] [|pigmentation], and can be caused by any of a large number of mutations in a single gene that codes for an [|enzyme] ([|phenylalanine hydroxylase]) that converts the [|amino acid] [|phenylalanine] to [|tyrosine], another amino acid. Depending on the mutation involved, this results in reduced or zero conversion of phenylalanine to tyrosine, and phenylalanine concentrations increase to toxic levels, causing damage at several locations in the body. PKU is totally benign if a diet free from phenylalanine is maintained.

1.8. Which of the following does not mess up the results of a calculation done using Hardy-Weinberg principle?

b. Non-random mating This may alter a gene pool in a way that is not accounted for by the Hardy-Weinberg principle. c. Small Population Size This may alter a gene pool in a way that is not accounted for by the Hardy-Weinberg principle. d. Medicinal Palliative Effects This may alter a gene pool in a way that is not accounted for by the Hardy-Weinberg principle.
 * a. Random mating** Random mating is expected when using the Hardy-Weinberg principle.

1.9. If there are 3 new cases of an autosomal dominant disease (with no family history) in 300 live births what is the mutation rate (µ)?

b) .01 c) 1 in 300 d) 1 in 150
 * a) .005** There are mutations in 3 alleles in a population of 600 alleles (µ = 3/600 = .005)

__2. Genome organization__
2.1. Which of the following histone subunits is not a part of the nucleosome?

b) H2A c) H2B d) H3 e) H4
 * a) H1** H1 is not a part of the histone octomer ( wikipedia ).

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