Mutations

Question 1

Name 3 types of mutagens and give an example

Answer 1

Physical mutagen - UV rays from sun
Chemical mutagen - Nicotine
Biological agent - HPV virus

Question 2

What are the 4 types of chromosome structure changes in chromosome mutation

Answer 2

• Deletion: Part of a chromosome is lost entirely
• Inversion: One region of a chromosome is broken, flipped and reinserted
• Translocation: Region of one chromosome is attached to another chromosome
• Duplication: Section of a chromosome is repeated

Question 3

What is a mutation?

Answer 3

A random permanent change in a genetic sequence

Question 4

What is a point mutation?

Answer 4

Occurs in a genome when a single base pair is added or changed

Question 5

What are 4 types of point mutations and their definition

Answer 5

• Substitution: One pair is swapped with another
• Insertion: When a pair is added
• Deletion: When a pair is removed
• Inversion: When a pair is swapped with an existing one in the sequence

Question 6

How do mutations occur?

Answer 6

• May arise spontaneously during DNA replication or cell division
• May be physical, chemical or environmental factors (mutagens)

Question 7

What are 3 effects of mutations?

Answer 7

• Neutral: Does not dramatically change amino acids, protein produced is unchanged
• Deleterious: Deletes, impairs or enhances protein activity in a way that is harmful to the organism
• Beneficial: Alters protein activity in a way that benefits the organism

Question 8

What are 3 effects can physical mutagens have on DNA?

Answer 8

• Can fuse bases together
• Can break DNA strands
• Can delete bases and leave gaps

Question 9

What are 3 examples of physical mutagens and their effects?

Answer 9

• UV light: Fuses bases to distort DNA
• X-rays: Causes loss of bases, leaving gaps in DNA
• Nuclear radiation: Causes double-stranded breaks in DNA, repair mechanisms may fuse wrong strands together

Question 10

What are 3 effects can chemical mutagens have on DNA?

Answer 10

• Add or remove bases
• Cross-link bases distorting DNA shape and affecting replication
• Cause major changes in chromosomal structure

Question 11

What is horizontal gene transfer?

Answer 11

When biological mutagens (pathogens) insert their DNA into a host’s genome. eg. Human papilloma virus (HPV)