Question 1

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

Accepted Answer

Genotype is the genetic makeup that determines the phenotype, which is the observable traits.

Question 2

Which of the following statements correctly compares the organization of genetic material in prokaryotic and eukaryotic cells?

Accepted Answer

Prokaryotic cells usually have a single circular chromosome in the nucleoid, while eukaryotic cells have multiple linear chromosomes in the nucleus.

Question 3

Which of the following is a unique feature of plasmid DNA in bacteria?

Accepted Answer

Plasmid DNA is an extrachromosomal, usually circular DNA that often confers survival advantages such as antibiotic resistance.

Question 4

Which of the following best describes the structure of a DNA nucleotide?

Accepted Answer

A phosphate group, a deoxyribose sugar, and a nitrogen base (A, T, G, or C)

Question 5

Which of the following statements about the directionality of DNA is correct?

Accepted Answer

DNA strands are antiparallel, with one running 5' to 3' and the other 3' to 5'.

Question 6

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

Accepted Answer

Helicase

Question 7

In the process of DNA replication, what is the role of DNA polymerase III?

Accepted Answer

It is the main enzyme that adds nucleotides to the growing DNA strand in the 5' to 3' direction.

Question 8

Which of the following best explains why Okazaki fragments are formed during DNA replication?

Accepted Answer

The lagging strand is synthesized discontinuously because DNA polymerase can only add nucleotides in the 5' to 3' direction.

Question 9

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

Accepted Answer

RNA contains ribose sugar, is usually single-stranded, and uses uracil instead of thymine.

Question 10

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 11

A mutation occurs in the gene encoding DNA ligase in a bacterium. Which process would be most directly affected?

Accepted Answer

Sealing of nicks in the DNA sugar-phosphate backbone during replication

Question 12

Which of the following is true regarding the genetic code?

Accepted Answer

There are 64 possible codons, but only 20 standard amino acids.

Question 13

In eukaryotic cells, where does transcription occur and which enzyme is primarily responsible?

Accepted Answer

Transcription occurs in the nucleus and is performed by RNA polymerase.

Question 14

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

Accepted Answer

tRNA contains an anticodon that pairs with the mRNA codon and brings the correct amino acid to the ribosome.

Question 15

Which of the following is an example of post-translational modification?

Accepted Answer

Addition of a phosphate group to a protein after translation

Question 16

Which of the following statements about operons is correct?

Accepted Answer

Repressible operons are usually ON and can be turned OFF when not needed.

Question 17

A bacterial cell is exposed to a new antibiotic. Which type of gene is most likely to be expressed in response to this environmental change?

Accepted Answer

Facultative gene

Question 18

Which of the following is a mechanism of pre-transcriptional regulation of gene expression?

Accepted Answer

DNA methylation that prevents transcription

Question 19

In bacteria, what is the primary purpose of quorum sensing?

Accepted Answer

To coordinate gene expression in response to population density

Genetics: Heredity, Genomes, and Gene Expression in Microbiology

Study Guide - Practice Questions