Unit 1 - 4.1 - Cell Mutations

Question 1

What are Mutations?

Answer 1

Changes in DNA that can result in either no protein being synthesised of the synthesis of an altered protein

• They can vary from a tiny change in DNA structure to a large-scale alteration in chromosome structure and number.

Question 2

How often do mutations occur?

Answer 2

Gene mutations arise spontaneously and at random, but only occurs rarely

Question 3

List the two mutagenic agents and give examples of each

Answer 3

Radiation
* UV lights, x-rays, gamma rays
Chemicals
* Mustard gas, bromine gas

Question 4

List the 2 types of mutation

Answer 4

• Single gene mutations
• Chromosome structure mutations

Question 5

• What is a single gene mutation?
• List the 3 types

Answer 5

Alteration of a DNA sequence as a result of a nucleotide being either substituted, deleted, or inserted.
* Substitution
* Deletion
* Insertion

Question 6

• What are chromosome structure mutations?
• List the 4 types

Answer 6

Alterations that affect whole chromosomes and whole genes rather than just individual nucleotides
* Duplication
* Inversion
* Deletion
* Translocation

Question 7

How do chromosome structure mutations occur?

Answer 7

They result from errors in cell division that cause a section of a chromosome to break off, be duplicated or move onto another chromosome.

Question 8

What is a frame-shift mutation?

Answer 8

• The insertion and deletion of a nucleotide results in a frame shift mutation
• It causes all of the codons and amino acids after the mutation to be changed. This has a major affect on the protein produced
• When the codons are read at the ribosome, the codon reading frame is shifted by 1