3.8.1 Consequence of DNA mutations Flashcards Preview

SHHS - Science - NEW AQA A-Level Biology (Year 2) > 3.8.1 Consequence of DNA mutations > Flashcards

Flashcards in 3.8.1 Consequence of DNA mutations Deck (25)
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1

Mutations are

changes to the base sequence of DNA

2

Mutations occur through errors during..

DNA replication

3

mutation rate can be increased by

mutagenic agents

4

Types of mutations that can occur include:

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

5

substitution mutation is when...

one or more bases are swapped for another

6

Effect of substitution mutations can be..

1. no effect (silent - if same AA coded for)
2. change triplet code - different AA coded for

7

deletion mutations is when

a one or more bases are removed

8

Effect of a deletion mutation...

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

9

Addition mutations are when

one or more bases are added

10

Effect of an addition mutation...

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

11

An inversion mutation is when..

a sequence of bases is reversed

12

A duplication mutation is when...

one or more bases are duplicated/repeated

13

A translocation mutation is when..

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

14

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

determine the order of the amino acids in the protein

15

chains of amino acids make

polypeptides

16

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

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

17

genetic mutations can cause certain disorders e.g.

cystic fibrosis, cancers

18

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

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

19

examples of mutagenic agents include

UV radiation, ionising radiation, chemicals, some viruses

20

mutations that occur in cells post fertilisation are called..

acquired mutations

21

Name 2 genes that control cell division

proto-oncogenes and tumour suppressor genes

22

Mutations in genes that control cell division can lead to ...

uncontrolled cell growth - tumour formation

23

Define a tumour..

a mass of abnormal cells that divides out of control

24

Cancer is...

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

25

Why is the genetic code described as being universal?

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