Question 1

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

Accepted Answer

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

Question 2

What is the significance of the 5’ and 3’ ends in a DNA strand?

Accepted Answer

They indicate the direction in which DNA polymerase can add nucleotides during DNA synthesis

Question 3

Which base pairing is correct in double-stranded DNA?

Accepted Answer

Adenine pairs with Thymine, Guanine pairs with Cytosine

Question 4

Why do G:C base pairs require more energy to separate than A:T base pairs?

Accepted Answer

G:C pairs have three hydrogen bonds, while A:T pairs have two

Question 5

Which enzyme catalyzes the formation of the phosphodiester bond between nucleotides during DNA replication?

Accepted Answer

DNA polymerase

Question 6

A mutation changes an adenine to a cytosine in a gene. What is the most direct effect of this mutation?

Accepted Answer

It alters the DNA sequence, which may change the encoded protein

Question 7

Which of the following statements about mitochondrial DNA is TRUE?

Accepted Answer

It is circular, double-stranded, and encodes some of its own proteins

Question 8

What is the main purpose of chromosomes in eukaryotic cells?

Accepted Answer

To compact and organize DNA, preventing tangling and damage

Question 9

During Sanger sequencing, what is the role of dideoxynucleotides (ddNTPs)?

Accepted Answer

They terminate DNA synthesis at specific bases, allowing sequence determination

Question 10

A human somatic cell contains 46 chromosomes. How many chromosomes are present in a human gamete?

Accepted Answer

23

Question 11

Which of the following best describes the difference between autosomes and sex chromosomes in humans?

Accepted Answer

Autosomes are chromosomes 1-22, sex chromosomes are X and Y

Question 12

Which of the following is a correct description of the directionality of DNA synthesis?

Accepted Answer

DNA is synthesized in the 5’ to 3’ direction

Question 13

Which of the following is NOT a function of chromosomes?

Accepted Answer

Synthesizing ATP for the cell

Question 14

Which of the following best explains why mitochondrial DNA does not appear in a karyotype analysis?

Accepted Answer

It is not compacted at metaphase and is not located in the nucleus

Question 15

A chromosome is described as 5q32. What does this notation indicate?

Accepted Answer

Chromosome 5, long arm, region 32

Question 16

Which of the following statements about the X and Y chromosomes is correct?

Accepted Answer

The X chromosome is larger and contains more genes than the Y chromosome

Question 17

Which of the following best describes the process of karyotyping?

Accepted Answer

Arranging and analyzing chromosomes from a metaphase spread to detect large-scale genetic changes

Question 18

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

Accepted Answer

Nuclear DNA is inherited from both parents, mitochondrial DNA is inherited maternally

Question 19

Which of the following best explains why DNA is described as a double helix?

Accepted Answer

It consists of two strands twisted around each other, held together by base pairing

Question 20

A patient’s Sanger sequencing results show a single nucleotide change in a gene. What is the most likely consequence?

Accepted Answer

The change may alter the protein encoded by the gene, potentially causing disease

DNA, Chromosomes, and Sequencing: Cell Biology Study Guide

Study Guide - Practice Questions