Q: Which of the following is true regarding the directionality of DNA synthesis?

DNA is synthesized in the $$5' \to 3'$$ direction.

Question 1

Which of the following best describes the base pairing rules for DNA and RNA, respectively?

Accepted Answer

DNA: A-T, G-C; RNA: A-U, G-C

Question 2

During DNA replication, which enzyme is responsible for synthesizing the new DNA strand by adding nucleotides to the growing chain?

Accepted Answer

DNA polymerase

Question 3

A mutation changes the DNA codon AAA (which codes for lysine) to AAG. Both codons code for lysine. What type of mutation is this?

Accepted Answer

Silent mutation

Question 4

Which of the following statements about the lac operon is correct?

Accepted Answer

It is an example of gene regulation where genes are only expressed when needed, such as in the presence of lactose.

Question 5

Which process involves the uptake of naked DNA from the environment by a bacterial cell?

Accepted Answer

Transformation

Question 6

A bacterium receives a plasmid carrying an antibiotic resistance gene from another bacterium through direct cell-to-cell contact. What is this process called?

Accepted Answer

Conjugation

Question 7

Which of the following best describes generalized transduction?

Accepted Answer

A bacteriophage accidentally packages host chromosomal DNA and transfers it to another bacterium.

Question 8

During translation, what is the role of tRNA?

Accepted Answer

To carry specific amino acids to the ribosome and match them to the mRNA codon using its anticodon.

Question 9

Which of the following is a possible outcome of a missense mutation?

Accepted Answer

A different amino acid is incorporated into the protein, potentially altering its function.

Question 10

Which enzyme is responsible for joining Okazaki fragments on the lagging strand during DNA replication?

Accepted Answer

DNA ligase

Question 11

A scientist exposes bacteria to UV radiation, resulting in DNA damage. What type of mutation is most likely to occur?

Accepted Answer

Radiation-induced mutation

Question 12

Which of the following best explains why beneficial mutations are more likely to be preserved in a population than harmful ones?

Accepted Answer

Beneficial mutations increase fitness and are selected for by natural selection.

Question 13

Which of the following is true regarding the directionality of DNA synthesis?

Accepted Answer

DNA is synthesized in the $$5' 	o 3'$$ direction.

Question 14

A bacterial cell is able to produce a new protein only when a specific sugar is present in the environment. This is an example of:

Accepted Answer

Inducible gene regulation

Question 15

Which of the following statements about plasmids is correct?

Accepted Answer

Plasmids are small, circular, autonomously replicating DNA molecules that can carry genes such as antibiotic resistance.

Question 16

Which of the following best describes the difference between generalized and specialized transduction?

Accepted Answer

Generalized transduction can transfer any gene from the donor, while specialized transduction transfers only specific genes near the prophage site.

Question 17

If a mutation results in a stop codon being introduced prematurely into an mRNA sequence, what is the likely result?

Accepted Answer

A truncated, nonfunctional protein due to a nonsense mutation.

Question 18

Which of the following is a key difference between F+ and Hfr bacterial cells?

Accepted Answer

F+ cells have the F plasmid as an independent element, while Hfr cells have the F plasmid integrated into their chromosome.

Question 19

A researcher is studying a gene that is always expressed in a bacterial cell, regardless of environmental conditions. This gene is best described as:

Accepted Answer

Constitutive

Question 20

Which of the following best explains why DNA polymerase has a low error rate during replication?

Accepted Answer

It has proofreading activity that corrects mismatched nucleotides.

Genetics and Microbial Genetics: DNA Structure, Function, and Gene Transfer

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