Question 1

Which statement best describes the 'central dogma' of molecular biology?

Accepted Answer

Genetic information flows from DNA to RNA to protein.

Question 2

Which enzyme is responsible for relieving supercoiling ahead of the replication fork during DNA replication?

Accepted Answer

Gyrase

Question 3

During DNA replication, the lagging strand is synthesized in short fragments known as Okazaki fragments. Which feature of DNA structure necessitates this process?

Accepted Answer

The anti-parallel orientation of DNA strands

Question 4

A DNA sequence is transcribed and translated in a prokaryote. If the DNA template strand reads 5'-TACGGA-3', what is the corresponding mRNA sequence and the amino acids encoded? (Use a codon table)

Accepted Answer

mRNA: 5'-AUGGGA-3'; Amino acids: Methionine-Glycine

Question 5

Which of the following best describes the difference between prokaryotic and eukaryotic protein synthesis?

Accepted Answer

Eukaryotes process mRNA by removing introns and joining exons before translation.

Question 6

Which of the following is a correct description of a missense mutation?

Accepted Answer

A mutation that changes one amino acid to another.

Question 7

A bacterial cell is exposed to UV light, which causes thymine dimers. Which DNA repair mechanism is most likely to fix this damage?

Accepted Answer

Excision repair

Question 8

Which of the following best explains why RNA viruses evolve faster than DNA viruses?

Accepted Answer

RNA viruses lack proofreading during replication.

Question 9

Which of the following is NOT a criterion used to classify viruses?

Accepted Answer

Ability to form endospores

Question 10

Antigenic shift in influenza viruses is most likely to result in:

Accepted Answer

Major changes in viral genome due to reassortment of gene segments

Question 11

Which of the following best describes the process of conjugation in bacteria?

Accepted Answer

Transfer of DNA through direct cell-to-cell contact using a pilus

Question 12

Which of the following is a medically important consequence of phage conversion?

Accepted Answer

Bacteria acquire new traits, such as toxin production, from bacteriophage genes.

Question 13

Which of the following best describes a plasmid?

Accepted Answer

A small, circular DNA molecule separate from the bacterial chromosome

Question 14

Which staining method would you use to identify Mycobacterium tuberculosis in a clinical sample, and why?

Accepted Answer

Acid-fast stain, because Mycobacterium has a waxy cell wall that retains the stain.

Question 15

Which of the following correctly lists the four solutions used in order for a Gram stain procedure?

Accepted Answer

Crystal violet, iodine, alcohol, safranin

Question 16

A bacterial cell is observed under the microscope and appears as chains of spherical cells. Which term best describes this arrangement?

Accepted Answer

Streptococcus

Question 17

Which of the following best explains the basis for differentiation between Gram positive and Gram negative bacteria in the Gram stain?

Accepted Answer

Gram positive bacteria have a thick peptidoglycan layer that retains crystal violet.

Question 18

Which of the following is a feature of negative simple staining?

Accepted Answer

Uses an acidic dye that stains the background, leaving cells unstained.

Question 19

Which equation best represents semi-conservative DNA replication?

Accepted Answer

$$	ext{Parent DNA} ightarrow 	ext{2 Daughter DNA (each with 1 old and 1 new strand)}$$

Question 20

Which of the following is a correct description of the Ames test?

Accepted Answer

A test used to determine if a chemical can cause mutations in bacteria.

Microbiology Module 2 Study Guide – Step-by-Step Guidance

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