Question 1

A geneticist crosses a true-breeding 2 cm mountain rose with a true-breeding 14 cm rose and obtains all 8 cm F1 progeny. When F1s are crossed, the F2 generation shows a range of stem lengths from 2 to 14 cm, with 14 cm roses occurring at a frequency of $$\frac{1}{64}. $$How many genes are likely involved in determining stem length in these roses?

Accepted Answer

3 genes

Question 2

In the F2 generation of the mountain rose cross, how many distinct phenotypic classes of stem length should be observed if the trait is controlled by three additive genes, each with two alleles?

Accepted Answer

$$2n + 1 = 7$$ phenotypic classes

Question 3

A true-breeding 6 cm rose from the F2 is crossed to a 14 cm rose, producing all 10 cm progeny. What is the most likely genotype of the 10 cm progeny if three additive genes control stem length?

Accepted Answer

AaBbCc

Question 4

Which of the following best describes the difference between a prototroph and an auxotroph?

Accepted Answer

A prototroph can grow on minimal media, while an auxotroph requires additional nutrients.

Question 5

The Luria-Delbrück fluctuation assay provided evidence for which of the following?

Accepted Answer

Mutations in bacteria are spontaneous and random.

Question 6

Which process involves the uptake of naked DNA fragments from the environment by a bacterial cell, followed by recombination with the host genome?

Accepted Answer

Transformation

Question 7

In bacterial conjugation, what is the role of the F factor?

Accepted Answer

It allows the formation of a pilus for DNA transfer.

Question 8

Which experimental result would best support the hypothesis that horizontal gene transfer, not vertical gene transfer, is responsible for the appearance of prototrophic colonies in a mixed culture of two auxotrophic bacterial strains?

Accepted Answer

Prototrophic colonies appear only when the two strains are grown together.

Question 9

Which of the following statements about bacteriophage-mediated transduction is correct?

Accepted Answer

It involves the transfer of bacterial DNA via a viral vector.

Question 10

A bacterial culture is in the log phase of growth. If the number of cells at the start of the log phase is $$10^3$$ and the doubling time is 30 minutes, how many cells will there be after 3 hours?

Accepted Answer

$$8 	imes 10^3$

Question 11

Which of the following best describes the lysogenic cycle of a bacteriophage?

Accepted Answer

The phage DNA integrates into the host genome and replicates with it.

Question 12

Which laboratory technique is commonly used to introduce foreign DNA into eukaryotic cells using positively charged lipids?

Accepted Answer

Lipofection

Question 13

A scientist wants to distinguish between spontaneous and adaptive mutations in bacteria. Which experimental approach should they use?

Accepted Answer

Perform a fluctuation test with multiple independent cultures and compare the variance in mutant numbers.

Question 14

Which of the following is NOT a requirement for bacterial conjugation to occur?

Accepted Answer

A bacteriophage to mediate DNA transfer

Question 15

In a U-tube experiment, two bacterial strains are separated by a filter that allows medium but not cells to pass. After incubation, no prototrophic colonies are observed. What does this result suggest?

Accepted Answer

Cell-to-cell contact is required for genetic recombination.

Question 16

Which of the following best explains why the F factor is not transmitted extracellularly during bacterial conjugation?

Accepted Answer

Cell-to-cell contact is required for transfer.

Question 17

Which of the following is a key difference between transformation and transfection?

Accepted Answer

Transformation occurs in prokaryotes, while transfection refers to the process in eukaryotes.

Question 18

Which of the following statements about horizontal gene transfer is correct?

Accepted Answer

It allows genetic material to move between unrelated cells.

Question 19

A bacterium is infected by a bacteriophage that integrates its DNA into the host genome and remains dormant. What is this integrated viral DNA called?

Accepted Answer

Prophage

Genetic Analysis and Mapping in Bacteria and Quantitative Genetics in Plants

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