Question 1

Which scientist's experiment using radioactive isotopes in bacteriophages provided strong evidence that DNA, and not protein, is the genetic material?

Accepted Answer

Hershey and Chase

Question 2

A nucleotide consists of which of the following components?

Accepted Answer

A phosphate group, a deoxyribose sugar, and a nitrogenous base

Question 3

Which of the following best describes the antiparallel structure of DNA?

Accepted Answer

The two strands run in opposite directions: one 5' to 3', the other 3' to 5'

Question 4

During DNA replication, which enzyme is responsible for relieving the tension ahead of the replication fork by cutting and rejoining DNA strands?

Accepted Answer

Topoisomerase

Question 5

Which of the following statements correctly compares DNA replication in prokaryotes and eukaryotes?

Accepted Answer

Prokaryotes have a single origin of replication, while eukaryotes have multiple origins.

Question 6

What is the function of the poly-A tail added to eukaryotic mRNA during processing?

Accepted Answer

It protects mRNA from degradation and assists in export from the nucleus.

Question 7

Which of the following best describes a nucleosome?

Accepted Answer

DNA wrapped around a core of histone proteins

Question 8

How does DNA methylation typically affect gene expression in eukaryotes?

Accepted Answer

It represses gene expression by preventing transcription.

Question 9

Which of the following is a correct statement about the direction in which RNA polymerase reads the DNA template during transcription?

Accepted Answer

RNA polymerase reads the template strand in the 3' to 5' direction.

Question 10

A mutation changes the codon $$\mathrm{UAC} ($$tyrosine) to $$\mathrm{UAA} ($$stop codon). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 11

Which of the following best describes the function of a restriction enzyme in genetic engineering?

Accepted Answer

It cuts DNA at specific sequences, allowing insertion of genes into plasmids.

Question 12

Which of the following is true about the lac operon in E. coli?

Accepted Answer

It is an inducible operon that is activated in the presence of lactose.

Question 13

Which of the following modifications occurs to pre-mRNA before it becomes mature mRNA in eukaryotes?

Accepted Answer

Addition of a 5' cap, splicing out introns, and addition of a poly-A tail

Question 14

Which of the following best describes the role of miRNA in gene regulation?

Accepted Answer

It binds to complementary mRNA sequences to inhibit translation.

Question 15

A scientist inserts a gene for human insulin into a bacterial plasmid and uses restriction enzymes to cut and paste the DNA. What is the main advantage of using plasmids in this process?

Accepted Answer

Plasmids can replicate independently and express foreign genes in bacteria.

Question 16

Which of the following is a similarity in protein synthesis between prokaryotes and eukaryotes?

Accepted Answer

Both use ribosomes to translate mRNA into protein.

Question 17

Which of the following best describes the function of the TATA box in eukaryotic transcription?

Accepted Answer

It is a promoter sequence that helps position RNA polymerase.

Question 18

If a DNA template strand has the sequence $$5'	ext{-}ATGCGTACG	ext{-}3'$$, what is the sequence of the mRNA transcribed from this strand?

Accepted Answer

$$3'	ext{-}UACGCAUGC	ext{-}5'$$

Question 19

Which of the following is an example of epigenetic regulation of gene expression?

Accepted Answer

Methylation of cytosine bases in DNA

Question 20

A frameshift mutation is most likely to result from which of the following?

Accepted Answer

An insertion or deletion of a nucleotide

Molecular Basis of Inheritance and Gene Expression: DNA, RNA, and Gene Regulation

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