Question 1

Which of the following best describes the antiparallel structure of DNA as discovered by Watson and Crick?

Accepted Answer

The two DNA strands run in opposite directions: one from 5’ to 3’ and the other from 3’ to 5’.

Question 2

Chargaff’s rule states that in any DNA molecule:

Accepted Answer

The amount of adenine equals the amount of thymine, and the amount of cytosine equals the amount of guanine.

Question 3

A scientist isolates chromatin from a eukaryotic cell and observes that it is highly condensed and transcriptionally inactive. This chromatin is most likely:

Accepted Answer

Heterochromatin

Question 4

Which of the following best explains the role of histones in chromatin structure?

Accepted Answer

Histones are proteins that DNA wraps around to form nucleosomes, aiding in compaction.

Question 5

During transcription in eukaryotes, which sequence signals the start of a gene and is recognized by transcription factors?

Accepted Answer

Promoter

Question 6

A mutation changes a DNA codon from $$	ext{GAA} to$$ $$	ext{GAG}$$, but both codons code for glutamic acid. This is an example of:

Accepted Answer

Silent mutation

Question 7

Which of the following best describes the function of the 5’ cap added during RNA processing?

Accepted Answer

It protects mRNA from degradation and assists in ribosome binding during translation.

Question 8

A patient is diagnosed with a genetic disorder caused by a single nucleotide insertion in a coding region. What is the most likely consequence at the protein level?

Accepted Answer

A frameshift mutation, altering the reading frame and potentially producing a nonfunctional protein.

Question 9

Which enzyme is responsible for synthesizing RNA from a DNA template during transcription?

Accepted Answer

RNA polymerase

Question 10

A mutation changes a codon from $$	ext{UAC} ($$tyrosine) to $$	ext{UAA} ($$stop codon). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 11

Which of the following statements about the triplet code is correct?

Accepted Answer

Each codon consists of three nucleotides and specifies one amino acid.

Question 12

Which of the following best describes the function of aminoacyl-tRNA synthetases?

Accepted Answer

They attach the correct amino acid to its corresponding tRNA.

Question 13

A researcher observes that a segment of DNA is transcribed but not translated into protein. This segment is most likely:

Accepted Answer

An intron

Question 14

Which site on the ribosome holds the tRNA carrying the next amino acid to be added to the polypeptide chain?

Accepted Answer

A-site

Question 15

Which of the following best explains why a frameshift mutation is often more damaging than a point mutation?

Accepted Answer

Frameshift mutations alter the reading frame, potentially changing every amino acid downstream.

Question 16

Which process removes introns from pre-mRNA in eukaryotic cells?

Accepted Answer

RNA splicing

Question 17

A mutation in the TATA box of a gene’s promoter region would most likely affect:

Accepted Answer

The ability of transcription factors to bind and initiate transcription.

Question 18

Which of the following is true regarding the sugar-phosphate backbone of DNA?

Accepted Answer

It consists of alternating sugars and phosphates linked by covalent bonds.

Question 19

Which of the following best describes the relationship between codons and anticodons during translation?

Accepted Answer

Codons are found on mRNA and anticodons on tRNA, allowing complementary base pairing.

Question 20

A chemical mutagen causes a nucleotide-pair substitution in a gene. Which of the following outcomes is NOT possible?

Accepted Answer

A frameshift mutation

Study Guide: Molecular Basis of Inheritance & Gene Expression (Chapters 13 & 14)

Study Guide - Practice Questions

Study Guide - Flashcards