Question 1

Which of the following best describes the function of telomerase in eukaryotic cells?

Accepted Answer

It adds repetitive nucleotide sequences to the ends of chromosomes to prevent loss of genetic information during DNA replication.

Question 2

A scientist is using a plasmid as a cloning vector to insert a gene of interest into E. coli. Which property of plasmids makes them especially useful for this purpose?

Accepted Answer

They can replicate independently of the bacterial chromosome.

Question 3

During DNA replication, which enzyme is responsible for joining Okazaki fragments on the lagging strand?

Accepted Answer

DNA ligase

Question 4

A researcher is analyzing a DNA sequence and finds the following strand: 5'-ATGCCGTA-3'. What is the complementary DNA sequence?

Accepted Answer

3'-TACGGCAT-5'

Question 5

Which of the following best explains why the lac operon is considered an example of negative control of gene expression in bacteria?

Accepted Answer

A repressor protein binds to the operator to block transcription in the absence of lactose.

Question 6

Which of the following is a correct description of the role of the 3' poly-A tail in eukaryotic mRNA?

Accepted Answer

It increases mRNA stability and facilitates export from the nucleus.

Question 7

A culture of bacteria is growing in a batch culture system. The number of cells doubles every 30 minutes. If the initial population is $$1 	imes 10^3$ cells, how many cells will there be after 2 hours?

Accepted Answer

$$1.6 	imes 10^4$

Question 8

Which of the following statements about restriction enzymes is correct?

Accepted Answer

They recognize specific DNA sequences and cut the DNA at or near these sites.

Question 9

A patient is diagnosed with a bacterial infection caused by a facultative anaerobe. Which of the following best describes the growth characteristics of this organism?

Accepted Answer

It can grow in both the presence and absence of oxygen.

Question 10

Which of the following best describes the function of aminoacyl-tRNA synthetases during protein synthesis?

Accepted Answer

They attach the correct amino acid to its corresponding tRNA.

Question 11

A microbiologist is using mannitol salt agar to isolate bacteria from a skin swab. Which property of this medium makes it selective?

Accepted Answer

High NaCl concentration inhibits the growth of most bacteria except staphylococci.

Question 12

Which of the following is the final electron acceptor in aerobic respiration?

Accepted Answer

Oxygen ($$O_2)$$

Question 13

A bacterial culture is in the stationary phase of the growth curve. Which of the following best explains what is happening in the culture?

Accepted Answer

The rate of cell division equals the rate of cell death.

Question 14

Which of the following best describes the process of bioremediation?

Accepted Answer

The use of microorganisms to degrade environmental pollutants.

Question 15

A scientist is using the polymerase chain reaction (PCR) to amplify a segment of DNA. Which enzyme is essential for this process?

Accepted Answer

DNA polymerase

Question 16

Which of the following statements about the trp operon in E. coli is correct?

Accepted Answer

It is repressed when tryptophan is present in the environment.

Question 17

A researcher is performing a standard plate count to estimate the number of viable bacteria in a sample. Which of the following best describes what is being measured?

Accepted Answer

The number of colony-forming units (CFUs) per unit volume.

Question 18

Which of the following is a key difference between prokaryotic and eukaryotic gene regulation?

Accepted Answer

Eukaryotic gene regulation often involves post-transcriptional processing such as splicing and addition of a 5' cap and 3' poly-A tail.

Question 19

Which of the following best describes the role of bioinformatics in modern microbiology?

Accepted Answer

It uses computational tools to analyze and interpret biological data, such as genome sequences.

Question 20

A patient is infected with a bacterium that produces reactive oxygen species (ROS) during metabolism. Which of the following enzymes would help the bacterium survive oxidative stress?

Accepted Answer

Catalase

Microbiology Exam 2 Study Guide: Genetics, Gene Regulation, Biotechnology, and Microbial Growth

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