Q: Which of the following is a correct representation of Chargaff’s rules for DNA base pairing?

$$\text{A} = \text{T}$$ and $$\text{G} = \text{C}$$

Question 1

Which of the following statements best describes the antiparallel nature of DNA?

Accepted Answer

The two strands of DNA run in opposite directions, with one strand oriented 5’ to 3’ and the other 3’ to 5’.

Question 2

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

Accepted Answer

DNA ligase

Question 3

A scientist observes a mutation in a gene where a single nucleotide is substituted, resulting in a premature stop codon. What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 4

Which of the following best explains why sickle cell anemia is caused by a point mutation?

Accepted Answer

A single nucleotide substitution changes one amino acid in the hemoglobin protein.

Question 5

Which of the following is a correct representation of Chargaff’s rules for DNA base pairing?

Accepted Answer

$$	ext{A} = 	ext{T}$$ and $$	ext{G} = 	ext{C}$$

Question 6

During transcription, which of the following sequences would be transcribed from a DNA template strand with the sequence 3’-TACGGT-5’?

Accepted Answer

5’-AUGCCA-3’

Question 7

Which of the following best describes the role of the spliceosome in eukaryotic cells?

Accepted Answer

It removes introns from pre-mRNA and joins exons together.

Question 8

A mutation causes the deletion of a single nucleotide in the coding region of a gene. What is the most likely effect on the resulting protein?

Accepted Answer

A frameshift mutation, altering all downstream amino acids.

Question 9

Which of the following statements about the central dogma of molecular biology is correct?

Accepted Answer

Genetic information flows from DNA to RNA to protein.

Question 10

Which of the following is true regarding the start codon in mRNA translation?

Accepted Answer

The start codon is AUG, which codes for methionine.

Question 11

Which of the following best explains why alternative splicing increases protein diversity in eukaryotes?

Accepted Answer

It allows different combinations of exons to be joined, producing multiple proteins from one gene.

Question 12

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

Accepted Answer

RNA contains ribose sugar, while DNA contains deoxyribose.

Question 13

A patient is diagnosed with cystic fibrosis due to a deletion of three nucleotides in the CFTR gene. What is the most likely effect of this mutation?

Accepted Answer

A single amino acid is missing from the protein, potentially altering its function.

Question 14

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

Accepted Answer

It brings specific amino acids to the ribosome based on its anticodon sequence.

Question 15

Which of the following is a function of the signal peptide in protein synthesis?

Accepted Answer

It directs the ribosome to the endoplasmic reticulum for protein targeting.

Question 16

Which of the following best explains why a silent mutation does not affect the protein sequence?

Accepted Answer

The altered codon still codes for the same amino acid due to the redundancy of the genetic code.

Question 17

Which scientist(s) used bacteriophages to demonstrate that DNA is the genetic material?

Accepted Answer

Hershey and Chase

Question 18

Which of the following best describes the difference between free ribosomes and those bound to the endoplasmic reticulum?

Accepted Answer

Free ribosomes synthesize proteins that function in the cytosol, while bound ribosomes synthesize proteins for secretion or membrane insertion.

Question 19

A mutagen is best described as:

Accepted Answer

An agent that increases the frequency of mutations in DNA.

DNA Structure, Replication, and Protein Synthesis: Study Guide

Study Guide - Practice Questions

Study Guide - Flashcards