Q: Which of the following best describes the flow of genetic information in a cell, according to the central dogma?

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

Question 1

Which of the following best describes the flow of genetic information in a cell, according to the central dogma?

Accepted Answer

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

Question 2

A scientist is studying a bacterial cell that has acquired resistance to multiple antibiotics. Which genetic element is most likely responsible for this trait?

Accepted Answer

Resistance plasmid (R plasmid)

Question 3

During DNA replication, which enzyme is responsible for relieving the twisting stress ahead of the replication fork?

Accepted Answer

Topoisomerase

Question 4

Which of the following statements about DNA methylation is TRUE?

Accepted Answer

Prokaryotes methylate adenine, while eukaryotes methylate cytosine.

Question 5

A mutation causes a single base to be replaced in a gene, resulting in a change in one amino acid of the protein. What type of mutation is this?

Accepted Answer

Missense mutation

Question 6

Which of the following is a mechanism by which bacteria can acquire new genetic material from their environment, as demonstrated in Griffith’s experiment?

Accepted Answer

Transformation

Question 7

In eukaryotic cells, newly synthesized mRNA must be processed before translation. Which process removes non-coding regions from pre-mRNA?

Accepted Answer

Spliceosome-mediated splicing

Question 8

Which of the following best explains why the lagging strand is synthesized discontinuously during DNA replication?

Accepted Answer

DNA polymerase can only add nucleotides to the 3' OH end, and the two template strands run in opposite directions.

Question 9

A researcher exposes bacterial cells to UV radiation. Which specific DNA lesion is most likely to form, and what is its consequence?

Accepted Answer

Thymine dimer; distorts DNA and increases mutation risk

Question 10

Which of the following is TRUE regarding the energy source for DNA replication?

Accepted Answer

Energy comes from the phosphate bonds of incoming nucleotides.

Question 11

A scientist uses PCR to amplify a DNA sequence. If the initial amount of DNA is $$1 \ \mu g$$, how much DNA will be present after $$n$$ cycles, assuming perfect doubling each cycle?

Accepted Answer

$$1 \ \mu g 	imes 2^n$$

Question 12

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

Accepted Answer

Cutting DNA at specific palindromic sequences to defend against viruses

Question 13

Which of the following best describes the role of reverse transcriptase in recombinant DNA technology?

Accepted Answer

Synthesizes DNA from RNA templates

Question 14

A patient is diagnosed with a genetic disorder caused by a frameshift mutation. Which of the following best describes a frameshift mutation?

Accepted Answer

A base is inserted or deleted, shifting the reading frame and altering all downstream codons

Question 15

Which of the following is a real-world application of recombinant DNA technology in agriculture?

Accepted Answer

Engineering crops to produce insecticidal proteins for pest resistance

Question 16

Which DNA repair mechanism is specifically activated by visible light to correct UV-induced thymine dimers?

Accepted Answer

Light repair (photoreactivation)

Question 17

A bacterial cell with an integrated F plasmid (Hfr cell) undergoes conjugation with an F− cell. What is the most likely outcome?

Accepted Answer

The recipient remains F− but acquires some chromosomal genes.

Question 18

Which of the following statements about operons in prokaryotes is correct?

Accepted Answer

Operons allow coordinated regulation of multiple genes under one promoter.

Question 19

Which of the following is a plausible consequence of error-prone SOS repair in bacteria?

Accepted Answer

High mutation rate, allowing survival under severe DNA damage

Question 20

A scientist wants to identify mutant bacteria that are resistant to an antibiotic. Which method should they use?

Accepted Answer

Positive selection

Genetics and Recombinant DNA Technology in Microbiology

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