3.8.1 DNA Mutations (Unit 8 Gene Expression)

Question 1

Mutations are

Answer 1

changes to the base sequence of DNA

Question 2

Mutations occur through errors during..

Answer 2

DNA replication

Question 3

mutation rate can be increased by

Answer 3

mutagenic agents

Question 4

Types of mutations that can occur include:

Answer 4

1. substitution
2. deletion/addition
3. duplication
4. inversion
5. translocation

Question 5

substitution mutation is when…

Answer 5

one or more bases are swapped for another

Question 6

Effect of substitution mutations can be..

Answer 6

1. no effect (silent - if same AA coded for)

2. change triplet code - different AA coded for

Question 7

deletion mutations is when

Answer 7

a one or more bases are removed

Question 8

Effect of a deletion mutation…

Answer 8

frameshift to the left - changes the entire triplet code from that point on - changes amino acid sequence

Question 9

Addition mutations are when

Answer 9

one or more bases are added

Question 10

Effect of an addition mutation…

Answer 10

frame shift to the right - changes the triplet code from that point on - changes the amino acid sequence

Question 11

An inversion mutation is when..

Answer 11

a sequence of bases is reversed

Question 12

A duplication mutation is when…

Answer 12

one or more bases are duplicated/repeated

Question 13

A translocation mutation is when..

Answer 13

a sequence of bases is moved from one location to another (could be in the same chromosome or different)

Question 14

What is significant about the order of the bases in DNA?

Answer 14

determine the order of the amino acids in the protein

Question 15

chains of amino acids make

Answer 15

polypeptides

Question 16

A change in the amino acid sequence of a protein means…

Answer 16

it may not fold properly, altering its tertiary structure - rendering it non-functional.

Question 17

genetic mutations can cause certain disorders e.g.

Answer 17

cystic fibrosis, cancers

Question 18

Why do not all mutations affect the order of the amino acids?

Answer 18

degenerative nature of genetic code - some AA coded for by more than 1 triplet code

Question 19

examples of mutagenic agents include

Answer 19

UV radiation, ionising radiation, chemicals, some viruses

Question 20

mutations that occur in cells post fertilisation are called..

Answer 20

acquired mutations

Question 21

Name 2 genes that control cell division

Answer 21

proto-oncogenes and tumour suppressor genes

Question 22

Mutations in genes that control cell division can lead to …

Answer 22

uncontrolled cell growth - tumour formation

Question 23

Define a tumour..

Answer 23

a mass of abnormal cells that divides out of control

Question 24

Cancer is…

Answer 24

a tumour that invades and destroys surrounding tissue and made spread to other parts of the body

Question 25

Why is the genetic code described as being universal?

Answer 25

The triplet codes code for the same amino acids in all organisms