Q: A bacterial strain that cannot grow in the presence of methionine is named:

methionine auxotroph ($$\text{met}^{-})$$

Q: A triple heterozygote is testcrossed, and 1,000 progeny are counted. If two genes are 10 map units apart, and one gene is 30 map units apart from the others, how many double crossovers are expected?

$$0.03 \times 0.10 \times 1000 = 3$$

Question 1

In a dihybrid cross AaBb x AaBb, what is the expected phenotypic ratio in the F2 generation, assuming independent assortment and complete dominance?

Accepted Answer

$$9:3:3:1$$

Question 2

A woman with blood type O has a child with blood type O. Which of the following men could NOT be the father?

Accepted Answer

A man with blood type AB

Question 3

If two genes are linked and 20 map units apart, what percentage of offspring from a testcross will be recombinants?

Accepted Answer

$$20\%$$

Question 4

A fruit fly with genotype AaBb is testcrossed. What is the probability that the first three offspring are all dihybrid females?

Accepted Answer

$$(1/8)^3 = 0.002$

Question 5

In a pedigree, if all daughters but none of the sons have a genetic disease, how is the trait most likely inherited?

Accepted Answer

X-linked dominant

Question 6

A bacterial strain that cannot grow in the presence of methionine is named:

Accepted Answer

methionine auxotroph ($$	ext{met}^{-})$$

Question 7

During conjugation in bacteria, which cell type can donate the F factor?

Accepted Answer

F$$^{+}$$ cell

Question 8

In an interrupted mating experiment, gene a first appears at 7 minutes, and gene b first appears at 12 minutes. What is the order of transfer?

Accepted Answer

$$a \rightarrow b$$

Question 9

A plant with genotype TtYy is crossed with ttYy. What is the expected proportion of offspring with genotype TtYy?

Accepted Answer

$$1/4$$

Question 10

If a male fruit fly is heterozygous for detached wings (dw) and is self-fertilized, what is the probability that all three offspring are females with detached wings?

Accepted Answer

$$(1/4)^3 = 1/64$

Question 11

How many tetrads are there in metaphase I of meiosis in human beings?

Accepted Answer

$$23$$

Question 12

Which of the following is a purine?

Accepted Answer

guanine

Question 13

A triple heterozygote is testcrossed, and 1,000 progeny are counted. If two genes are 10 map units apart, and one gene is 30 map units apart from the others, how many double crossovers are expected?

Accepted Answer

$$0.03 	imes 0.10 	imes 1000 = 3$$

Question 14

A woman is a carrier for hemophilia (X-linked recessive). If she has a son with hemophilia, which statement is most accurate?

Accepted Answer

She should not blame the accident because she carried the hemophilia allele.

Question 15

In a bacterial transformation experiment, which process allows DNA to be taken up from the environment?

Accepted Answer

transformation

Question 16

If a tomato plant with genotype aa bb cc is crossed with Aa Bb Cc, what is the probability that the offspring will be aa bb cc?

Accepted Answer

$$(1/2)^3 = 1/8$

Question 17

Which of the following best describes the stage of cell division shown in a diagram with chromosomes aligned at the center and a diploid number of 4?

Accepted Answer

metaphase of mitosis, $$2n = 4$$

Question 18

A male human with an XYY sex chromosome complement would be classified as:

Accepted Answer

male

Question 19

If a fruit fly is an animal diploid for its autosomes but has one X and two Y chromosomes, what is its sex?

Accepted Answer

male

Question 20

Which of the following is NOT a possible mode of inheritance for a trait that appears in every generation and affects both males and females equally?

Accepted Answer

X-linked recessive

Genetics: Principles, Inheritance, and Problem Solving – Study Guide

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