Heredity and Genetics Quiz
Oct. 17/2005
1. A karyotype of a human could be expected to show:
a) 46 chromatids, from 23 homologous chromosome pairs
b) any non-disjunction mutations, such as trisomy and monosomy
c) the mutation of a single nucleotide in the DNA sequence
d) both a and b
2. If two parents, one of blood type A and one of type B, have a type-O child, what must
be true?
a) one of the parents must be heterozygous with a i allele, that is IAi or IBi
b) this is not possible
c) both parents must be heterozygous
d) a mutation occurred
3. Pleiotropy refers to:
a) multiple alleles each having partial control of one trait
b) the control of more than one trait by a single allele
c) multiple alleles having co-dominant control of a trait
d) the tendency for alleles on the same chromosome to be inherited together
4. Imagine Mendel crosses a homozygous dominant round-seeded pea plant (RR) with a
heterozygous plant (Rr). What phenotypic ratio would occur in the F1 generation?
a) all round
b) 3 round : 1 wrinkled
c) 1 round : 1 wrinkled
d) all wrinkled
5. Mendel’s colleague, Brother Cadfael, wants one of the F1 offspring from #4, but needs
to know its genotype. What could Mendel do to find this out?
a) cross it with a homozygous dominant plant
b) cross it with a homozygous recessive plant
c) cross it with another F1 Plant
d) wait until it produces seeds
6. Mendel’s law of independent assortment:
a) is not true in all circumstances, given what we know of modern genetics
b) states that different alleles for the same trait assort independently
c) states that alleles for different traits assort independently
d) both a and c
7. A male with Jacob’s syndrome (having an XYY genotype) could be the result of:
a) non-disjunction of the Y chromosome during the first meiotic division
b) non-disjunction of the Y chromosome during the second meiotic division
c) non-disjunction in either the mother or father
d) both b and c
8. For a sex-linked trait located on the human X chromosome:
a) males will always express the allele inherited from their mothers, being
homozygous for this
b) females may be homozygous or heterozygous for a triat, but randomly express
only one allele
c) females always express the dominant allele
d) both a and b
9. Which of the following were inaccuracies of Mendel’s genetic model?
a) Mendel concluded that alleles for all traits assort independently
b) it did not account for traits influenced by multiple alleles
c) it did not account for the influence of environment on phenotype
d) all of the above
10. You observe that a population of Dryas occidentalis growing on top of a mountain
(population A) produces plants with smaller leaves than those growing at a lower
elevation (pop. B). To find out whether this is an environmental influence on phenotype,
what would you do?
a) cross-breed plants from populations A and B in a greenhouse
b) locate a pure-breeding strain, C, and cross-breed it with A and B
c) collect seeds from several plants in populations A & B, and grow them in a
controlled environment
d) any of these would work
Key
1. d
2. c
3. b
4. a
5. b
6. d
7. b
8. d
9. d
10. c