Question 1

Which of the following best describes the relationship between genotype and phenotype in an organism?

Accepted Answer

Genotype is the genetic makeup, which interacts with the environment to produce the phenotype.

Question 2

Which of the following statements about prokaryotic and eukaryotic genomes is CORRECT?

Accepted Answer

Prokaryotic genomes are usually circular and found in the nucleoid region, while eukaryotic genomes are linear and found in the nucleus.

Question 3

Which enzyme is responsible for relieving the tension caused by unwinding the DNA helix during replication in bacteria?

Accepted Answer

DNA gyrase

Question 4

A mutation changes the codon GAG (glutamic acid) to GTG (valine) in the beta chain of hemoglobin. This is an example of which type of mutation?

Accepted Answer

Missense mutation

Question 5

Which of the following is a function of plasmids in bacteria?

Accepted Answer

They often confer a survival advantage, such as antibiotic resistance.

Question 6

During DNA replication, which strand is synthesized discontinuously and why?

Accepted Answer

The lagging strand, because DNA polymerase can only add nucleotides in the 5' to 3' direction, resulting in Okazaki fragments.

Question 7

Which of the following best describes the central dogma of molecular biology?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 8

Which of the following is NOT a possible outcome of a base substitution (point mutation)?

Accepted Answer

Frameshift mutation

Question 9

Which of the following best explains why the genetic code is described as 'degenerate'?

Accepted Answer

More than one codon can specify the same amino acid.

Question 10

A scientist exposes a bacterial culture to ultraviolet light, which causes the formation of thymine dimers. What is the most likely effect on the DNA?

Accepted Answer

Thymine dimers will distort the DNA molecule, potentially stalling replication and leading to cell death if not repaired.

Question 11

Which of the following is TRUE regarding horizontal gene transfer in bacteria?

Accepted Answer

It allows bacteria to acquire genes from other organisms, not just from parent to offspring.

Question 12

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

Accepted Answer

tRNA brings the correct amino acid to the ribosome and matches its anticodon with mRNA codons.

Question 13

Which of the following is a real-life example of a disease caused by a point mutation?

Accepted Answer

Sickle-cell disease caused by a single base substitution

Question 14

Which of the following is a function of DNA ligase during DNA replication?

Accepted Answer

Joins Okazaki fragments together by forming covalent bonds between nucleotides

Question 15

Which of the following best describes a frameshift mutation?

Accepted Answer

A mutation caused by the insertion or deletion of nucleotides not in multiples of three, altering the reading frame

Question 16

Which of the following is a key difference between DNA and RNA?

Accepted Answer

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

Question 17

Which of the following is the correct sequence of events during bacterial conjugation?

Accepted Answer

Donor cell forms F pilus, contracts to pull cells together, transfers plasmid DNA, both cells become F+

Question 18

Which of the following best explains why E. coli is a good model organism for genetic studies?

Accepted Answer

It grows rapidly, produces large numbers, and its genetics are well understood.

Question 19

Which of the following is a possible outcome of exposure to a chemical mutagen such as nitrous acid?

Accepted Answer

Conversion of cytosine to uracil, increasing the chance of incorrect nucleotide incorporation.

Microbial Genetics: Structure, Function, and Genetic Change

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