Biology Module 6: Mendelian Genetics Flashcards


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1

Use the following information to answer the questions below.

Two true-breeding stocks of pea plants are crossed. One parent has red, axial flowers and the other has white, terminal flowers; all F1 individuals have red, axial flowers. The genes for flower color and location assort independently.


Among the F2 offspring, what is the probability of plants with white axial flowers?

3/16

2

Which of the following provides an example of epistasis?

In rabbits and many other mammals, one genotype (cc) prevents any fur color from developing.

3
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Use the following pedigree (Figure 14.3) for a family in which dark-shaded symbols represent individuals with one of the two major types of colon cancer. Numbers under the symbols are the individual's age at the time of diagnosis.


Figure 14.3


What is the genotype of the deceased individual in generation II?

heterozygous for a gene for colon cancer

4

Use the following information to answer the questions below.

Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The part of the radish we eat may be oval or long, with long being the dominant characteristic.


In the F2 generation of the above cross, which of the following phenotypic ratios would be expected?

6:3:3:2:1:1

5

Use the information given here to answer the following questions.

Feather color in budgies is determined by two different genes, Y and B, one for pigment on the outside and one for the inside of the feather. YYBB, YyBB, or YYBb is green; yyBB or yyBb is blue; YYbb
or Yybb is yellow; and yybb is white.


A blue budgie is crossed with a white budgie. Which of the following results is not possible?

green and yellow offspring

6

Use the following information to answer the questions below.

A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M
and N.


If both children are of blood type M, which of the following is possible?

Each parent is either M or MN.

7

Two plants are crossed, resulting in offspring with a 3:1 ratio for a particular trait. What does this suggest?

that the parents were both heterozygous for a single trait

8

Use the information given here to answer the following questions.

Feather color in budgies is determined by two different genes, Y and B, one for pigment on the outside and one for the inside of the feather. YYBB, YyBB, or YYBb is green; yyBB or yyBb is blue; YYbb
or Yybb is yellow; and yybb is white.


Two blue budgies were crossed. Over the years, they produced 22 offspring, 5 of which were white. What are the most likely genotypes for the two blue budgies?

yyBb and yyBb

9

Which of the following describes the ability of a single gene to have multiple phenotypic effects?

pleiotropy

10

Use the following information to answer the questions below.

A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M
and N.


Which of the following is a possible genotype for the mother?

IAi

11

Use the following information to answer the questions below.

Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The part of the radish we eat may be oval or long, with long being the dominant characteristic.

The flower color trait in radishes is an example of which of the following?

incomplete dominance

12

What do we mean when we use the terms monohybrid cross and dihybrid cross?

A dihybrid cross involves organisms that are heterozygous for two characters and a monohybrid cross involves only one.

13

Use the following information to answer the questions below.

A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M
and N.


Which of the following is a possible phenotype for the father?

B positive

14
card image

Use Figure 14.1 and the following description to answer the questions below.

In a particular plant, leaf color is controlled by gene locus D. Plants with at least one allele D have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding dark-leaved plant is crossed with a light-leaved one, and the F1 offspring is allowed to self-pollinate. The predicted outcome of the F2 is diagrammed in the Punnett square shown in Figure 14.1, where 1, 2, 3, and 4 represent the genotypes corresponding to each box within the square.


Figure 14.1


Which of the plants will be true-breeding?

1 and 4 only

15

A sexually reproducing animal has two unlinked genes, one for head shape (H) and one for tail length (T). Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this organism?

HT

16
card image

The following questions refer to the pedigree chart in Figure 14.2 for a family, some of whose members exhibit the dominant trait, W. Affected individuals are indicated by a dark square or circle.


Figure 14.2


What is the genotype of individual II-5?Correct!

ww

17

Given the parents AABBCc x AabbCc, assume simple dominance for each trait and independent assortment. What proportion of the progeny will be expected to phenotypically resemble the first parent?

3/4

18

Mendel accounted for the observation that traits which had disappeared in the F1 generation reappeared in the F2 generation by proposing that

traits can be dominant or recessive, and the recessive traits were obscured by the dominant ones in the F1.

19

Mendel's observation of the segregation of alleles in gamete formation has its basis in which of the following phases of cell division?

anaphase I of meiosis

20

Mendel's second law of independent assortment has its basis in which of the following events of meiosis I?

alignment of tetrads at the equator

21

Use the following information to answer the questions below.

Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The part of the radish we eat may be oval or long, with long being the dominant characteristic.


If true-breeding red long radishes are crossed with true-breeding white oval radishes, the F1 will be expected to be which of the following?

purple and long

22
card image

The following questions refer to the pedigree chart in Figure 14.2 for a family, some of whose members exhibit the dominant trait, W. Affected individuals are indicated by a dark square or circle.


Figure 14.2


What is the probability that individual III-1 is Ww?

1

23

Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long tails (t). What fraction of the progeny of crosses BbTt x BBtt
will be expected to have black fur and long tails?

1/2

24

Hydrangea plants of the same genotype are planted in a large flower garden. Some of the plants produce blue flowers and others pink flowers. This can be best explained by which of the following?

environmental factors such as soil pH

25

Use the following information to answer the questions below.

Tallness (T) in snapdragons is dominant to dwarfness (t), while red (R) flower color is dominant to white (r). The heterozygous condition results in pink (Rr) flower color.


If snapdragons are heterozygous for height as well as for flower color, a mating between them will result in what ratio?

6:3:3:2:1:1

26

Cystic fibrosis affects the lungs, the pancreas, the digestive system, and other organs, resulting in symptoms ranging from breathing difficulties to recurrent infections. Which of the following terms best describes this?

pleiotropy

27
card image

The following questions refer to the pedigree chart in Figure 14.2 for a family, some of whose members exhibit the dominant trait, W. Affected individuals are indicated by a dark square or circle.


Figure 14.2


What is the likelihood that the progeny of IV-3 and IV-4 will have the trait?

50%

28

When crossing an organism that is homozygous recessive for a single trait with a heterozygote, what is the chance of producing an offspring with the homozygous recessive phenotype?

50%

29

Use the following information to answer the questions below.

Tallness (T) in snapdragons is dominant to dwarfness (t), while red (R) flower color is dominant to white (r). The heterozygous condition results in pink (Rr) flower color.


A dwarf, red snapdragon is crossed with a plant homozygous for tallness and white flowers. What are the genotype and phenotype of the F1 individuals?

TtRr-tall and pink

30
card image

Use Figure 14.1 and the following description to answer the questions below.

In a particular plant, leaf color is controlled by gene locus D. Plants with at least one allele D have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding dark-leaved plant is crossed with a light-leaved one, and the F1 offspring is allowed to self-pollinate. The predicted outcome of the F2 is diagrammed in the Punnett square shown in Figure 14.1, where 1, 2, 3, and 4 represent the genotypes corresponding to each box within the square.


Figure 14.1


Which of the boxes correspond to plants with a heterozygous genotype?

2 and 3

31

In the cross AaBbCc x AaBbCc, what is the probability of producing the genotype AABBCC?

1/64

32

Which of the following is an example of polygenic inheritance?

skin pigmentation in humans

33

Use the following information to answer the questions below.

Drosophila (fruit flies) usually have long wings (+) but mutations in two different genes can result in bent wings (bt) or vestigial wings (vg).


If a homozygous bent wing fly is mated with a homozygous vestigial wing fly, which of the following offspring would you expect?

all +bt +vg heterozygotes

34

Marfan syndrome in humans is caused by an abnormality of the connective tissue protein fibrillin. Patients are usually very tall and thin, with long spindly fingers, curvature of the spine, sometimes weakened arterial walls, and sometimes ocular problems, such as lens dislocation. Which of the following would you conclude about Marfan syndrome from this information?

It is pleiotropic.

35

Use the following information to answer the questions below.

A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r, respectively. A third gene for the MN blood group has codominant alleles M
and N.


Which of the following is a possible partial genotype for the son?

IBi

36

In certain plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short?

0

37

In cattle, roan coat color (mixed red and white hairs) occurs in the heterozygous (Rr) offspring of red (RR) and white (rr) homozygotes. Which of the following crosses would produce offspring in the ratio of 1 red:2 roan:1 white?

roan x roan

38
card image

Use Figure 14.1 and the following description to answer the questions below.

In a particular plant, leaf color is controlled by gene locus D. Plants with at least one allele D have dark green leaves, and plants with the homozygous recessive dd genotype have light green leaves. A true-breeding dark-leaved plant is crossed with a light-leaved one, and the F1 offspring is allowed to self-pollinate. The predicted outcome of the F2 is diagrammed in the Punnett square shown in Figure 14.1, where 1, 2, 3, and 4 represent the genotypes corresponding to each box within the square.


Figure 14.1


Which of the boxes marked 1-4 correspond to plants with dark leaves?

1, 2, and 3

39

Use the following information to answer the questions below.

Drosophila (fruit flies) usually have long wings (+) but mutations in two different genes can result in bent wings (bt) or vestigial wings (vg).


If flies that are heterozygous for both the bent wing gene and the vestigial wing gene are mated, what is the probability of offspring with bent wings only?

3/16