Mutations (18.3)

Question 1

Define: Mutation

Answer 1

A permanent change in the genetic material of an organism

Question 2

How do mutations spread throughout the body?

Answer 2

All mutations are inheritable; they are copied during DNA replication and passed on to daughter cells

Question 3

Which mutations are passed on to future generations?

Answer 3

Only mutations that affect the genetic information in the gametes of an organism are passed on to the organism’s offspring (germ line mutations)

Question 4

Define: Gametes

Answer 4

The reproductive cells

Question 5

What are somatic cell mutations?

Answer 5

Mutations that occur in the body cells

Question 6

What are germ line mutations?

Answer 6

Mutations that occur in reproductive cells

Question 7

What are germ line mutations?

Answer 7

Mutations that occur in reproductive cells

Question 8

Define: Point Mutations

Answer 8

Genetic mutations that occur when one or a few nucleotides are changed in a DNA sequence

Question 9

What is the one type of point mutation?

Answer 9

Substitution mutation

Question 10

What is a substitution mutation?

Answer 10

When a nucleotide in a DNA sequence is replaced by a different nucleotide

Question 11

What is a frameshift mutation?

Answer 11

Genetic mutations that occur when a nucleotide is either added or deleted from a DNA sequence, resulting in a shift of the “reading frame” of the genetic code

Question 12

What are the two types of frameshift mutations?

Answer 12

1. Insertions
2. Deletions

Question 13

What is an insertion mutation?

Answer 13

An extra base is slipped in

Question 14

What is a deletion mutation?

Answer 14

A base is removed/missing

Question 15

What are the three types of substitution mutations?

Answer 15

1. Missense mutation: results in an altered protein (e.g. sickle cell anemia)
2. Silent mutation: has no effect on a cell’s metabolism
3. Nonsense mutation: renders gene unable to code for a functional polypeptide

Question 16

What type of protein does a missense mutation result in?

Answer 16

Slightly altered but still functional protein (e.g. sickle cell anemia)

Question 17

What type of protein does a silent mutation result in?

Answer 17

Has no effect on the protein made

Question 18

What type of protein does a nonsense mutation result in?

Answer 18

Renders gene unable to code for a functional polypeptide

Question 19

What are the two ways mutations are caused?

Answer 19

Mutations may be spontaneous (DNA polymerase incorrectly pairing nucleotides) or induced by a mutagen

Question 20

What are the two types of mutagens

Answer 20

Chemical, physical and infectious mutagens

Question 21

How does a physical mutagen cause mutations

Answer 21

By forcibly breaking a nucleotide sequence causing random changes

Question 22

What are some examples of physical mutagens?

Answer 22

• X-ray
• UV radiation

Question 23

How does a chemical mutagen cause mutations?

Answer 23

• Enters cell’s nucleus and causes permanent change in genetic material by chemically reacting with DNA (nitrates)
• Most are carcinogenic (cancer-causing)

Question 24

What are some examples of chemical mutagens?

Answer 24

• Cigarette smoke
• Benzoyl peroxide

Question 25

Most chemical mutagens are _____________.

Answer 25

Carcinogenic

Question 26

What are infectious mutagens?

Answer 26

Bacterial or viral pathogens

Question 27

What are some examples of infectious mutagens?

Answer 27

- HPV virus - Helicobacter pylori (bacteria spread through contaminated food)