Question 1

If a trait that is not expressed in the F1 generation reappears in the F2 generation,the inheritance of the trait in question is an example of

Accepted Answer

A)  codominance. 
B)  dominance and recessiveness. 
C)  incomplete dominance. 
D)  epistasis. 
E)  a test cross.

Question 2

Use the following to answer questions :
Cleft chin is an X-linked dominant trait.Assume that a man with a cleft chin marries a woman with a round chin.
-What percent of their female progeny will show the cleft chin trait?

Accepted Answer

A)  0 percent 
B)  25 percent 
C)  50 percent 
D)  75 percent 
E)  100 percent

Question 3

A pea plant with red flowers is test crossed,and one-half of the resulting progeny have red flowers,while the other half has white flowers.Therefore,the genotype of the test-crossed parent was

Accepted Answer

A)  RR. 
B)  Rr. 
C)  rr. 
D)  either RR or Rr. 
E)  either Rr or rr.

Question 4

In cocker spaniels,black color (B)is dominant over red (b),and solid color (S)is dominant over spotted (s).If the genes are unlinked,and the offspring of BBss and bbss individuals are mated with each other,what fraction of the next generation will be black and spotted?

Accepted Answer

A)  1/16 
B)  9/16 
C)  1/9 
D)  3/16 
E)  3/4

Question 5

Commercial chicken breeders will cross two different breeds of chickens (e.g. ,White Rocks and White Cornish)to create a fast growing chicken that is larger than either of the parental breeds.This result is best explained by the phenomenon of

Accepted Answer

A)  true breeding. 
B)  incomplete dominance. 
C)  hybrid vigor. 
D)  expressivity. 
E)  blending inheritance.

Question 6

When reciprocal crosses produce identical results,one can conclude that the trait is

Accepted Answer

A)  not sex-linked. 
B)  sex-linked. 
C)  not autosomally inherited. 
D)  expressed on both X and Y chromosomes. 
E)  due to a hemizygous gene.

Question 7

Use the following to answer questions :
Suppose members of a true-breeding strain of salamanders with yellow stripes are crossed with a true-breeding strain with red stripes.Red and yellow are two alleles of the same gene.The resulting offspring have both yellow stripes and red stripes.
-What pattern would you expect in the F2 generation?

Accepted Answer

A)  Half will have yellow stripes,and half will have red stripes. 
B)  Half will have both yellow and red stripes,one-quarter will have just yellow stripes,and one-quarter will have just red stripes. 
C)  One-third will have both yellow and red stripes,one-third will have just yellow stripes,and one-third will have just red stripes. 
D)  Half will have both yellow and red stripes,and half will be stripeless. 
E)  One-quarter will have both yellow and red stripes,half will have just yellow stripes,and one-quarter will have just red stripes.

Question 8

If two strains of true-breeding plants that have different alleles for a certain character are crossed,their progeny are called

Accepted Answer

A)  the F1 generation. 
B)  the P generation. 
C)  the F2 generation. 
D)  F1 crosses. 
E)  F2 progeny.

Question 9

Use the following to answer questions :
In a species of tortoise,foot size (big or small)is controlled by one gene,while shell shape (round or lumpy)is controlled by another gene.Suppose that a big-footed lumpy-shelled tortoise mates with a small-footed round-shelled tortoise.Eight offspring result: four big-footed round-shelled tortoises and four small-footed round-shelled tortoises.(Assume that the parents are not necessarily homozygous for each allele. )
-If big feet (B)in tortoises is dominant to small feet (b),what is the genotype of the big-footed parent with respect to the foot gene?

Accepted Answer

A)  bb 
B)  BB 
C)  Bb 
D)  Either bb or BB 
E)  Either bb and Bb

Question 10

Humans have 46 chromosomes and _______ autosomes.

Accepted Answer

A)  23 pairs of 
B)  22 pairs of 
C)  1 pair of 
D)  45 
E)  16

Question 11

Alleles for genes located on mitochondrial DNA are said to be maternally inherited.What is the reason for this pattern of inheritance?

Accepted Answer

A)  The egg and sperm contribute equal numbers of cytoplasmic organelles to the zygote. 
B)  The egg contributes virtually all of the cytoplasmic organelles to the zygote. 
C)  Half of the nuclear chromosomes in the zygote come from the father. 
D)  Half of the nuclear chromosomes in the zygote come from the mother. 
E)  All of the nuclear chromosomes in the zygote come from the mother.

Question 12

When a dihybrid black,normal-winged fly is crossed with a double-recessive gray,vestigial-winged fly,the frequency with which black vestigial-winged and gray normal-winged flies are seen in the progeny is called the _______ frequency.

Accepted Answer

A)  mutation 
B)  mitotic 
C)  meiotic 
D)  allele 
E)  recombination

Question 13

Despite the law of independent assortment,when two loci are on the same chromosome,the phenotypes of the progeny sometimes do not fit the predicted phenotypes.This outcome can be explained by the phenomenon of

Accepted Answer

A)  translocation. 
B)  inversions. 
C)  epistasis. 
D)  linkage. 
E)  conjugation.

Question 14

The parents of individuals in the F2 generation are members of the _______ generation.

Accepted Answer

A)  P 
B)  F1 
C)  F2 
D)  F3 
E)  M

Question 15

Which statement about Mendelian genetics is false?

Accepted Answer

A)  Alternative forms of genes are called alleles. 
B)  A locus is a gene's location on its chromosome. 
C)  In any population,only two alleles can exist for a given gene. 
D)  A genotype is a description of an individual's alleles. 
E)  Individuals with the same phenotype can have different genotypes.

Question 16

Use the following to answer questions :
Egg and Fluffy are two linked bird genes that are 16 map units apart.The E allele of Egg produces large eggs and the e allele produces small eggs (E is dominant).The F allele produces fluffy feathers and the f allele produces nonfluffy feathers (F is dominant).
-If EeFf is crossed with eeff,what proportion of female offspring will produce small eggs and nonfluffy feathers?

Accepted Answer

A)  8 percent 
B)  16 percent 
C)  42 percent 
D)  84 percent 
E)  100 percent

Question 17

White eyes is a recessive sex-linked trait in fruit flies.If a white-eyed female fruit fly is mated to a red-eyed male,their offspring should be

Accepted Answer

A)  50 percent red-eyed and 50 percent white-eyed for both sexes. 
B)  all white-eyed for both sexes. 
C)  all white-eyed males and all red-eyed females. 
D)  all white-eyed females and all red-eyed males. 
E)  50 percent red-eyed males,50 percent white-eyed males,and all red-eyed females.

Question 18

The complete phenotype of an organism is dependent on

Accepted Answer

A)  genotype. 
B)  penetrance. 
C)  expressivity. 
D)  environment. 
E)  All of the above

Question 19

A patient with blood type AB requires a blood transfusion.Which blood group would be rejected by the patient's immune system?

Accepted Answer

A)  A 
B)  B 
C)  O 
D)  AB 
E)  None of the above

Question 20

Different forms of a gene are called

Accepted Answer

A)  traits. 
B)  phenotypes. 
C)  genotypes. 
D)  alleles. 
E)  characters.

Exam 8: Inheritance, Genes, and Chromosomes

If a trait that is not expressed in the F₁ generation reappears in the F₂ generation,the inheritance of the trait in question is an example of

Use the following to answer questions : Cleft chin is an X-linked dominant trait.Assume that a man with a cleft chin marries a woman with a round chin. -What percent of their female progeny will show the cleft chin trait?