Q: Which of the following is a correct sequence of events in the central dogma of molecular biology?

$$\text{DNA} \rightarrow \text{RNA} \rightarrow \text{Protein}$$

Question 1

Which of the following best describes the main structural difference between prokaryotic and eukaryotic cells?

Accepted Answer

Prokaryotic cells lack a nucleus and other membrane-bound organelles, while eukaryotic cells possess these structures.

Question 2

A bacterium is found to survive in both the presence and absence of oxygen by switching its metabolic pathway. Which term best describes this organism?

Accepted Answer

Facultative anaerobe

Question 3

Which of the following is a correct pairing of a prokaryotic cell-surface structure and its function?

Accepted Answer

Capsule – protection from host immune system

Question 4

A scientist discovers a new prokaryote that uses light for energy and organic compounds as a carbon source. Which nutritional mode does this organism exhibit?

Accepted Answer

Photoheterotroph

Question 5

Which process is responsible for the transfer of genetic material between prokaryotic cells via a pilus, often involving plasmids?

Accepted Answer

Conjugation

Question 6

A virus with a single-stranded RNA genome and a membranous envelope infects a host cell. Which of the following statements is TRUE regarding its replication?

Accepted Answer

It must use the host cell's enzymes and ribosomes to synthesize viral proteins.

Question 7

Which of the following best explains why R plasmids are a concern in medical settings?

Accepted Answer

They carry genes for antibiotic resistance, allowing bacteria to survive treatment.

Question 8

During DNA replication, which enzyme is responsible for unwinding the double helix?

Accepted Answer

Helicase

Question 9

A mutation changes a codon from UAU (tyrosine) to UAA (stop codon). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 10

Which of the following best describes the difference between the lytic and lysogenic cycles of bacteriophages?

Accepted Answer

The lytic cycle results in host cell lysis and release of new phages, while the lysogenic cycle allows viral DNA to persist in the host genome without killing the cell.

Question 11

Which of the following is a correct sequence of events in the central dogma of molecular biology?

Accepted Answer

$$	ext{DNA} ightarrow 	ext{RNA} ightarrow 	ext{Protein}$$

Question 12

A eukaryotic cell is observed to have completed DNA replication but has not yet begun mitosis. In which phase of the cell cycle is this cell?

Accepted Answer

G$$_2$$ phase

Question 13

Which of the following best explains why a frameshift mutation often results in a non-functional protein?

Accepted Answer

It alters the reading frame, changing all downstream amino acids.

Question 14

Which of the following is TRUE regarding the difference between DNA and RNA?

Accepted Answer

DNA is usually double-stranded, while RNA is usually single-stranded.

Question 15

A patient is infected with a bacterium that is resistant to multiple antibiotics. Which genetic mechanism most likely contributed to this resistance?

Accepted Answer

Acquisition of R plasmids through conjugation

Question 16

Which of the following best describes the role of tRNA during translation?

Accepted Answer

It brings specific amino acids to the ribosome based on codon-anticodon pairing.

Question 17

Which of the following events occurs during anaphase of mitosis?

Accepted Answer

Sister chromatids separate and move toward opposite poles.

Question 18

A scientist observes a prokaryote moving toward a higher concentration of glucose. This behavior is best described as:

Accepted Answer

Chemotaxis

Question 19

Which of the following is a function of restriction enzymes in bacteria?

Accepted Answer

They cut foreign viral DNA, providing defense against phages.

Question 20

Which of the following best explains why DNA replication is described as 'semi-conservative'?

Accepted Answer

Each new DNA molecule consists of one original and one new strand.

Microbiology and Molecular Biology: Prokaryotes, Viruses, and Genetic Mechanisms

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