Question 1

Put the following structures in order from smallest to largest: Nucleus, Chromatin, Nucleotide (base), Double helix, Cell, Chromosome.

Accepted Answer

Nucleotide (base), Double helix, Chromatin, Chromosome, Nucleus, Cell

Question 2

A chromosome is approximately how many times wider than a DNA double helix?

Accepted Answer

$700 	imes$

Question 3

Which of the following can be determined by analyzing a karyotype?

Accepted Answer

Abnormal chromosome numbers and sex

Question 4

What is the main difference between a point mutation and a chromosomal structural mutation?

Accepted Answer

A point mutation affects a single nucleotide, while a chromosomal structural mutation affects large segments of a chromosome.

Question 5

Which type of mutation is responsible for sickle cell disease?

Accepted Answer

A point mutation (substitution)

Question 6

A mutation that adds or removes a single base pair in a gene is called:

Accepted Answer

An indel (insertion or deletion)

Question 7

What is the likely effect of a frameshift mutation near the beginning of a gene?

Accepted Answer

It will likely result in a non-functional protein due to a shift in the reading frame.

Question 8

Which of the following is NOT a cause of DNA mutation?

Accepted Answer

Inbreeding

Question 9

Why is inbreeding associated with an increased expression of genetic disorders?

Accepted Answer

It increases the chance of homozygous recessive offspring expressing deleterious alleles.

Question 10

Which chromosomal abnormality is associated with chronic myeloid leukemia (CML)?

Accepted Answer

Philadelphia chromosome (translocation between chromosomes 9 and 22)

Question 11

What is the role of histones in DNA packaging?

Accepted Answer

They are proteins that DNA wraps around to form nucleosomes.

Question 12

Which of the following best describes a nucleosome?

Accepted Answer

A segment of DNA wrapped around a core of histone proteins

Question 13

A silent mutation is best described as:

Accepted Answer

A change in DNA sequence that does not alter the amino acid sequence of the protein

Question 14

Which of the following species has the highest number of chromosome pairs according to the provided data?

Accepted Answer

Chicken

Question 15

A karyotype of a human with Down syndrome would show:

Accepted Answer

Three copies of chromosome 21

Question 16

If a DNA sequence is mutated from $	ext{TTC}$ to $	ext{TTT}$, what type of mutation is this and what is the likely effect?

Accepted Answer

Silent mutation; no change in amino acid

Question 17

Which of the following best explains why a frameshift mutation is usually more severe than a point substitution?

Accepted Answer

It changes the reading frame, potentially altering every amino acid downstream.

Question 18

Which of the following is true about the difference in chromosome numbers between humans and chimpanzees?

Accepted Answer

Humans have 23 pairs of chromosomes, while chimpanzees have 24 pairs.

Question 19

A mutation in the CFTR gene deletes three nucleotides, removing a phenylalanine residue. What type of mutation is this?

Accepted Answer

In-frame deletion (indel)

Question 20

Which of the following best describes a missense mutation?

Accepted Answer

A single nucleotide change that results in a different amino acid

Chromosome Packing and Mutations: Structure, Function, and Genetic Variation

Study Guide - Practice Questions