Question 1

In a complementation test, two true-breeding Drosophila mutants with black bodies are crossed and all F1 offspring have wild-type gray bodies. What does this result indicate?

Accepted Answer

Complementation occurred, so the mutations are in different genes.

Question 2

A plant of genotype $$CCdd is $$crossed to $$ccDD$$ and the F1 is testcrossed to $$ccdd. If $$the genes are 20 cM apart, what percentage of $$ccdd$$ recombinants will be observed?

Accepted Answer

$$20\%$$

Question 3

In Drosophila, the genes $$w$$ and $$sn$$ are X-linked and 25 map units apart. A female $$w^+ sn^+/w sn is $$crossed to a wild-type male. What percent of male progeny will be recombinant for $$w$$ and $$sn$$?

Accepted Answer

$$12.5\%$$

Question 4

In maize, two plants heterozygous for recessive alleles $$a$$ and $$b$$ are crossed. If $$a$$ and $$b$$ are 7.2 map units apart and in trans configuration, what is the expected frequency of double-mutant progeny?

Accepted Answer

$$0.005184$$

Question 5

How many phenotypic classes are expected in the progeny of a four-point testcross?

Accepted Answer

$$16$$

Question 6

Given the following testcross progeny in corn: red, 127; glossy, 153; wild-type, 352; glossy + red, 368. What is your best estimate of the map distance between glossy and red, in map units?

Accepted Answer

$$15.3$$

Question 7

If genes $$a$$ and $$b$$ are 10 map units apart, $$b$$ and $$c$$ are 20 map units apart, and $$a$$ and $$c$$ are 28 map units apart, how many double crossovers are expected among 1,000 progeny if there is no interference?

Accepted Answer

$$20$$

Question 8

If genes $$a$$ and $$b$$ are 10 map units apart, $$b$$ and $$c$$ are 20 map units apart, and $$a$$ and $$c$$ are 28 map units apart, how many double crossovers are expected among 1,000 progeny if interference $$= 0.5$$?

Accepted Answer

$$30$$

Question 9

If genes $$a$$ and $$b$$ are 10 map units apart, $$b$$ and $$c$$ are 20 map units apart, and $$a$$ and $$c$$ are 28 map units apart, how many progeny are expected from single crossovers between $$a$$ and $$b$$ among 1,000 progeny if there is no interference?

Accepted Answer

$$20$$

Question 10

A bacterial strain that requires an organic form of carbon is called:

Accepted Answer

heterotrophic

Question 11

A bacterial strain that has a nutritional requirement is called:

Accepted Answer

auxotrophic

Question 12

The process by which a phage transfers bacterial DNA between bacteria is called:

Accepted Answer

transduction

Question 13

A bacterial cell with the phenotype $$F^-$$:

Accepted Answer

can receive the F factor during conjugation

Question 14

In an interrupted mating experiment, gene $$a$$ first appears at 12 minutes, gene $$b at 7 $$minutes, and gene $$c at 5 $$minutes. What is the order of transfer?

Accepted Answer

cab

Question 15

The Hershey and Chase experiment using $$^{32}P$$ and $$^{35}S$$ demonstrated that:

Accepted Answer

phage DNA enters the host cell

Question 16

Which of the following is a purine?

Accepted Answer

guanine and adenine

Question 17

Antiparallel in DNA structure means:

Accepted Answer

DNA strands run in opposite directions

Question 18

The melting temperature of DNA increases as the:

Accepted Answer

G+C content increases

Question 19

If a double-stranded DNA molecule is $$28\% G$$, what percent of the bases is A?

Accepted Answer

$$22\%$$

Genetics Exam 2 Study Guide: Linkage, Mapping, Complementation, and DNA Biology

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