Question 1

In a cross between AaBbCcDdEe and AaBbccDdee, what proportion of the offspring would be expected to be A_bbC_ddE_? (A_ means AA or Aa.)

Accepted Answer

A) 3/256 
B) 3/32 
C) 3/16 
D) 3/8 
E) 3/4

Question 2

In dogs, black coat color (B)is dominant over brown (b), and solid coat color (S)is dominant over white spotted coat (s).A cross between a black, solid female and a black, solid male produces puppies with only black, solid coats.This same female was then mated with a brown, spotted male.Half of the offspring from this cross were black and solid, and half of the offspring were black and spotted.What is the genotype of the female?

Accepted Answer

A) BBSS 
B) BbSS 
C) BBSs 
D) BbSs 
E) bbss

Question 3

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b.What is the probability of producing an AB gamete from an AaBb individual?

Accepted Answer

A) 1/4 
B) 1/2 
C) 1/16 
D) 9/16 
E) 1 (100%)

Question 4

In poodles, black fur is dominant to white fur.A black poodle is crossed with a white poodle.In a litter of seven, all of the puppies are black.What is the BEST conclusion?

Accepted Answer

A) The black poodle is definitely homozygous. 
B) The black poodle is probably homozygous. 
C) The black poodle is definitely heterozygous. 
D) The black poodle is probably heterozygous. 
E) The genotype of the black poodle cannot be inferred with this information.

Question 5

Cystic fibrosis is a human recessive autosomal condition.If two heterozygous parents have two children, what is the probability that they will be born in the order: normal boy and affected girl?

Accepted Answer

A) 3/64 
B) 3/512 
C) 9/512 
D) 9/256 
E) 3/16

Question 6

What is the difference between a backcross and a testcross?

Accepted Answer

The answer of What is the difference between a backcross...

Question 7

Honeybees have a haplo-diploid sex determination system where females develop from a fertilized egg (they are diploid, having one allele from the female queen and one allele from the male), and males develop from unfertilized eggs (they are haploid, having only one allele from the queen).Assuming that the queen is heterozygous for a particular gene, what is the probability that a female will inherit the recessive allele from her mother? What is the probability that a male will inherit a recessive allele from his mother?

Accepted Answer

A) The probability that a daughter will inherit a recessive allele from her mother is 50%; the probability that a son will inherit a recessive allele from his mother is 50%. 
B) The probability that a daughter will inherit a recessive allele from her mother is 50%; the probability that a son will inherit a recessive allele from his mother is 100%. 
C) The probability that a daughter will inherit a recessive allele from her mother is 100%; the probability that a son will inherit a recessive allele from his mother is 50%. 
D) The probability that a daughter will inherit a recessive allele from her mother is 100%; the probability that a son will inherit a recessive allele from his mother is 100%. 
E) The probability that a daughter will inherit a recessive allele from her mother is 0%; the probability that a son will inherit a recessive allele from his mother is 100%.

Question 8

Two pea plants with purple flowers are crossed.Among the offspring, 63 have purple flowers, and 17 have white flowers.With a chi-square test, compare the observed numbers with a 3:1 ratio and determine if the difference between observed and expected could be a result of chance.

Accepted Answer

The answer of Two pea plants with purple flowers are...

Question 9

Which of the following crosses would produce a 3:1 ratio of phenotypes in the next generation?

Accepted Answer

A) AA × AA 
B) AA × aa 
C) Aa × Aa 
D) Aa × aa 
E) aa × aa

Question 10

Round seeds (R)is dominant to wrinkled seeds (r), and yellow seeds (Y)is dominant to green seeds (y).A true-breeding plant with round and yellow seeds is crossed to a true-breeding plant with wrinkled and green seeds.What is the genotype of the F1 progeny?

Accepted Answer

A) RRYY 
B) RrYY 
C) RRYy 
D) RrYy 
E) rryy

Question 11

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b.What is the probability of producing an AaBb zygote from a cross AaBb × AABB?

Accepted Answer

A) 1/4 
B) 1/2 
C) 1/16 
D) 9/16 
E) 1 (100%)

Question 12

In dogs, black coat color (B)is dominant over brown (b), and solid coat color (S)is dominant over white spotted coat (s).A cross between a black, solid female and a black, solid male produces puppies with only black, solid coats.This same female was then mated with a brown, spotted male.Half of the offspring from this cross were black and solid, and half of the offspring were black and spotted.Which of the following could be the genotype of the black, solid male?

Accepted Answer

A) BBSs 
B) BBss 
C) BbSS 
D) BbSs 
E) Bbss

Question 13

If an organism of genotype Aa is used for a testcross, what is the genotype of the other individual used in the cross?

Accepted Answer

A) AA 
B) Aa 
C) aa 
D) The genotype cannot be known. 
E) Either AA or Aa is correct.

Question 14

In a cross between pure-breeding tall plants with pure-breeding short plants, all of the F1 are tall.When these plants are allowed to fertilize themselves, the F2 plants occur in a ratio of 3 tall:1 short.Which of the following is NOT a valid conclusion from these results?

Accepted Answer

A) The allele that produces the tall condition is dominant to the allele that produces the short condition. 
B) The difference between tall and short stature in these lines is controlled by a single gene pair. 
C) During production of gametes in F1 plants, the tall and short alleles segregate from each other equally into the gametes. 
D) The tall and short traits assort independently of each other in this cross. 
E) Fertilization occurs randomly between gametes carrying the tall and short alleles.

Question 15

A chi-square test was performed and indicated that the observed numbers of offspring were significantly different from the expected.Which of the following P-values would support this conclusion?

Accepted Answer

A) 0)995 
B) 0)536 
C) 0)004 
D) 0)752 
E) 0)159

Question 16

Round seeds (R)is dominant to wrinkled seeds (r), and yellow seeds (Y)is dominant to green seeds (y).A true-breeding pea plant with round and yellow seeds is crossed to a true-breeding plant with wrinkled and green seeds.The F1 progeny are allowed to self-fertilize.What is the probability of obtaining a wrinkled, green seed in the F2?

Accepted Answer

A) 3/4 
B) 1/16 
C) 9/16 
D) 3/16 
E) 1/2

Question 17

Freckles are caused by a dominant allele.A man has freckles but one of his parents does not have freckles.What is his genotype?

Accepted Answer

A) Homozygous dominant 
B) Homozygous recessive 
C) Heterozygous 
D) Heterologous 
E) Homologous

Question 18

A pedigree shows that two parents are phenotypically normal, but one of their four biological children has a typical autosomal recessive trait.The other three children are phenotypically normal.It is very likely that:

Accepted Answer

A) the affected child is a girl. 
B) the affected child is a boy. 
C) the trait was expressed by one of the grandparents of the children. 
D) the parents are both heterozygous for the trait. 
E) if the affected child eventually marries a phenotypically normal spouse, all of the their children will have the trait.

Question 19

In animals, the inability to make the pigment melanin results in albinism, a recessive condition.Two unaffected parents, who have decided to have three children, have a first child that has albinism (genotype aa).What is the probability that the second and third children will also have albinism?

Accepted Answer

A) 1/4 
B) 1/2 
C) 1/16 
D) 9/16 
E) 1 (100%)

Question 20

In Labrador retrievers, black coat color is dominant to brown.Suppose that a black Lab is mated with a brown one, and the offspring are 4 black puppies and 1 brown.What can you conclude about the genotype of the black parent? (Assume that B is the allele for black and b is the allele for brown.)

Accepted Answer

A) The genotype must be BB. 
B) The genotype must be bb. 
C) The genotype must be Bb. 
D) The genotype could be either BB or Bb. 
E) The genotype cannot be determined from these data.

Exam 3: Basic Principles of Heredity

In a cross between AaBbCcDdEe and AaBbccDdee, what proportion of the offspring would be expected to be A_bbC_ddE_? (A_ means AA or Aa.)

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b.What is the probability of producing an AB gamete from an AaBb individual?

In poodles, black fur is dominant to white fur.A black poodle is crossed with a white poodle.In a litter of seven, all of the puppies are black.What is the BEST conclusion?

Cystic fibrosis is a human recessive autosomal condition.If two heterozygous parents have two children, what is the probability that they will be born in the order: normal boy and affected girl?

What is the difference between a backcross and a testcross?

Two pea plants with purple flowers are crossed.Among the offspring, 63 have purple flowers, and 17 have white flowers.With a chi-square test, compare the observed numbers with a 3:1 ratio and determine if the difference between observed and expected could be a result of chance.

Which of the following crosses would produce a 3:1 ratio of phenotypes in the next generation?

Round seeds (R) is dominant to wrinkled seeds (r) , and yellow seeds (Y) is dominant to green seeds (y) .A true-breeding plant with round and yellow seeds is crossed to a true-breeding plant with wrinkled and green seeds.What is the genotype of the F₁ progeny?

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b.What is the probability of producing an AaBb zygote from a cross AaBb × AABB?

If an organism of genotype Aa is used for a testcross, what is the genotype of the other individual used in the cross?

In a cross between pure-breeding tall plants with pure-breeding short plants, all of the F₁ are tall.When these plants are allowed to fertilize themselves, the F₂ plants occur in a ratio of 3 tall:1 short.Which of the following is NOT a valid conclusion from these results?

A chi-square test was performed and indicated that the observed numbers of offspring were significantly different from the expected.Which of the following P-values would support this conclusion?

Freckles are caused by a dominant allele.A man has freckles but one of his parents does not have freckles.What is his genotype?

A pedigree shows that two parents are phenotypically normal, but one of their four biological children has a typical autosomal recessive trait.The other three children are phenotypically normal.It is very likely that:

In animals, the inability to make the pigment melanin results in albinism, a recessive condition.Two unaffected parents, who have decided to have three children, have a first child that has albinism (genotype aa) .What is the probability that the second and third children will also have albinism?

In Labrador retrievers, black coat color is dominant to brown.Suppose that a black Lab is mated with a brown one, and the offspring are 4 black puppies and 1 brown.What can you conclude about the genotype of the black parent? (Assume that B is the allele for black and b is the allele for brown.)

Exam 3: Basic Principles of Heredity

In a cross between AaBbCcDdEe and AaBbccDdee, what proportion of the offspring would be expected to be A_bbC_ddE_? (A_ means AA or Aa.)

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b.What is the probability of producing an AB gamete from an AaBb individual?

In poodles, black fur is dominant to white fur.A black poodle is crossed with a white poodle.In a litter of seven, all of the puppies are black.What is the BEST conclusion?

Cystic fibrosis is a human recessive autosomal condition.If two heterozygous parents have two children, what is the probability that they will be born in the order: normal boy and affected girl?

What is the difference between a backcross and a testcross?

Two pea plants with purple flowers are crossed.Among the offspring, 63 have purple flowers, and 17 have white flowers.With a chi-square test, compare the observed numbers with a 3:1 ratio and determine if the difference between observed and expected could be a result of chance.

Which of the following crosses would produce a 3:1 ratio of phenotypes in the next generation?

Round seeds (R) is dominant to wrinkled seeds (r) , and yellow seeds (Y) is dominant to green seeds (y) .A true-breeding plant with round and yellow seeds is crossed to a true-breeding plant with wrinkled and green seeds.What is the genotype of the F1 progeny?

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b.What is the probability of producing an AaBb zygote from a cross AaBb × AABB?

If an organism of genotype Aa is used for a testcross, what is the genotype of the other individual used in the cross?

In a cross between pure-breeding tall plants with pure-breeding short plants, all of the F1 are tall.When these plants are allowed to fertilize themselves, the F2 plants occur in a ratio of 3 tall:1 short.Which of the following is NOT a valid conclusion from these results?

A chi-square test was performed and indicated that the observed numbers of offspring were significantly different from the expected.Which of the following P-values would support this conclusion?

Freckles are caused by a dominant allele.A man has freckles but one of his parents does not have freckles.What is his genotype?

A pedigree shows that two parents are phenotypically normal, but one of their four biological children has a typical autosomal recessive trait.The other three children are phenotypically normal.It is very likely that:

In animals, the inability to make the pigment melanin results in albinism, a recessive condition.Two unaffected parents, who have decided to have three children, have a first child that has albinism (genotype aa) .What is the probability that the second and third children will also have albinism?

In Labrador retrievers, black coat color is dominant to brown.Suppose that a black Lab is mated with a brown one, and the offspring are 4 black puppies and 1 brown.What can you conclude about the genotype of the black parent? (Assume that B is the allele for black and b is the allele for brown.)

Round seeds (R) is dominant to wrinkled seeds (r) , and yellow seeds (Y) is dominant to green seeds (y) .A true-breeding plant with round and yellow seeds is crossed to a true-breeding plant with wrinkled and green seeds.What is the genotype of the F₁ progeny?

In a cross between pure-breeding tall plants with pure-breeding short plants, all of the F₁ are tall.When these plants are allowed to fertilize themselves, the F₂ plants occur in a ratio of 3 tall:1 short.Which of the following is NOT a valid conclusion from these results?