3.8.1 DNA Mutations (Unit 8 Gene Expression) Flashcards

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1
Q

Mutations are

A

changes to the base sequence of DNA

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2
Q

Mutations occur through errors during..

A

DNA replication

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3
Q

mutation rate can be increased by

A

mutagenic agents

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4
Q

Types of mutations that can occur include:

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

substitution mutation is when…

A

one or more bases are swapped for another

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6
Q

Effect of substitution mutations can be..

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

2. change triplet code - different AA coded for

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7
Q

deletion mutations is when

A

a one or more bases are removed

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8
Q

Effect of a deletion mutation…

A

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

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9
Q

Addition mutations are when

A

one or more bases are added

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10
Q

Effect of an addition mutation…

A

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

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11
Q

An inversion mutation is when..

A

a sequence of bases is reversed

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12
Q

A duplication mutation is when…

A

one or more bases are duplicated/repeated

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13
Q

A translocation mutation is when..

A

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

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14
Q

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

A

determine the order of the amino acids in the protein

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15
Q

chains of amino acids make

A

polypeptides

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16
Q

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

A

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

17
Q

genetic mutations can cause certain disorders e.g.

A

cystic fibrosis, cancers

18
Q

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

A

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

19
Q

examples of mutagenic agents include

A

UV radiation, ionising radiation, chemicals, some viruses

20
Q

mutations that occur in cells post fertilisation are called..

A

acquired mutations

21
Q

Name 2 genes that control cell division

A

proto-oncogenes and tumour suppressor genes

22
Q

Mutations in genes that control cell division can lead to …

A

uncontrolled cell growth - tumour formation

23
Q

Define a tumour..

A

a mass of abnormal cells that divides out of control

24
Q

Cancer is…

A

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

25
Q

Why is the genetic code described as being universal?

A

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