Question 1

Which of the following statements best describes the difference between prokaryotic and eukaryotic genomes?

Accepted Answer

Eukaryotic genomes are typically organized into multiple linear chromosomes housed in a nucleus, whereas most prokaryotic genomes consist of a single circular chromosome located in the nucleoid region.

Question 2

Which nitrogenous base is found in RNA but not in DNA?

Accepted Answer

Uracil

Question 3

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

Accepted Answer

Helicase

Question 4

A scientist is studying a bacterial cell and observes that DNA replication is occurring continuously on one strand and discontinuously on the other. What is the name of the discontinuously synthesized fragments?

Accepted Answer

Okazaki fragments

Question 5

Which of the following best explains the antiparallel nature of DNA?

Accepted Answer

One DNA strand runs 5' to 3' and the complementary strand runs 3' to 5'.

Question 6

Which of the following base pairs is correct according to the rules of complementary base pairing in DNA?

Accepted Answer

$A$ pairs with $T$

Question 7

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

Accepted Answer

Synthesis of the leading and lagging DNA strands during replication

Question 8

Which of the following statements about plasmids is TRUE?

Accepted Answer

Plasmids are small, circular DNA molecules that exist outside the chromosomal DNA and often carry genes for antibiotic resistance.

Question 9

Which enzyme is responsible for joining Okazaki fragments together during DNA replication?

Accepted Answer

Ligase

Question 10

In the central dogma of molecular biology, what is the correct flow of genetic information?

Accepted Answer

DNA $\rightarrow$ RNA $\rightarrow$ Protein

Question 11

A researcher is analyzing a eukaryotic cell and finds that its DNA is tightly wound around proteins. What are these proteins called?

Accepted Answer

Histones

Question 12

Which of the following best describes the function of transfer RNA (tRNA) during protein synthesis?

Accepted Answer

tRNA brings amino acids to the ribosome and matches them to the coded mRNA message using its anticodon.

Question 13

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

Accepted Answer

DNA contains deoxyribose sugar, while RNA contains ribose sugar.

Question 14

A mutation in a gene results in a change from adenine (A) to guanine (G) in the DNA sequence. What type of mutation is this?

Accepted Answer

Point mutation

Question 15

Which of the following best explains why DNA replication is described as 'semiconservative'?

Accepted Answer

Each new DNA molecule consists of one parental strand and one newly synthesized strand.

Question 16

During transcription in prokaryotes, where does RNA polymerase bind to initiate transcription?

Accepted Answer

Promoter region

Question 17

Which of the following is a function of ribosomal RNA (rRNA)?

Accepted Answer

Forms the core structure of the ribosome and catalyzes peptide bond formation

Question 18

A chemical mutagen causes a base substitution in a gene. Which of the following outcomes is most likely?

Accepted Answer

A single nucleotide is changed, potentially altering the amino acid sequence of the protein.

Question 19

Which of the following best describes the role of the enzyme primase during DNA replication?

Accepted Answer

Primase synthesizes short RNA primers needed to start DNA synthesis.

Question 20

A patient is infected with a virus that uses reverse transcriptase. Which process does this enzyme catalyze?

Accepted Answer

Synthesis of DNA from an RNA template

Genomes, DNA Structure, Replication, and Protein Synthesis in Microbiology

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