SF1: DNA mutagenesis and mutation detection Flashcards Preview

BS1050: Genes > SF1: DNA mutagenesis and mutation detection > Flashcards

Flashcards in SF1: DNA mutagenesis and mutation detection Deck (20):
1

What are the three components of DNA? Which of these can be damaged?

  1. Bases (bonded with weak hydrogen bonds)
  2. Sugar ring (in the backbone)
  3. Phosphate group (in the backbone)

They can all be damaged.

2

What makes up a nucleotide?

DNA bases and the sugar-phosphate backbone

3

Define 'DNA mutation'

A change in DNA sequence or rearrangement of genetic material

4

What are the two reasons why a person has a DNA mutation?

Inheritied

  • Through parental germline, so passed on to offspring
  • e.g. people who have been exposed to radiation can pass mutations to offspring who were never exposed

Acquired

  • ​Somatic cells
  • Can accumulate and become malignant

5

What are the two main types of DNA mutation? Define them.

Micromutations – a change in the DNA sequence

Macromutations – rearrangements of genetic material

6

What are the three types of micromutation?

  • Deletion
  • Insertion
  • Substitution

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7

What are the five types of macromutation?

  • Deletion
  • Duplication
  • Inversion
  • Substitution
  • Translocation

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8

What are the five types of DNA mutation?

  • Silent
  • Missense
  • Nonsense
  • Frameshift
  • Gross change

9

What effects can a mutation in the non-coding region of DNA have?

  • Change product amount
  • Change product activity
  • No effect

10

Describe a silent mutation

A change in the base does not lead to a change in the amino acid sequence or protein due to the degenerate nature of DNA

11

Define 'missense mutation'

A mutation that changes an amino acid to another amino acid

12

Define 'nonsense mutation'

A mutation that causes a premature stop codon

13

What is a frameshift mutation?

A mutation that results in the loss or gain of multiples of amino acids other than three (e.g. 1, 2, 4, 5, 7)

14

What are four unnatural causes of DNA mutation?

  1. Ionising radiations/particles
  2. Free radicals
  3. Mutagenic agents
  4. Anti-cancer agents

15

What is the mechasnism of mutagenesis for unnatural causes of DNA damage such as ionising radiations?

DNA damage → defective or no DNA repair → mutation

16

What spontaneous events can lead to mutation?

  • DNA replication errors
  • Movement of transposable elements

17

What is the mechanism of mutagenesis for spontaneous events causing DNA damage?

Spontaneous events → mutation

18

How might mutations in parents' DNA affect their children?

Mutations in the germline will be inherited and may change the phenotype or predisposition in offspring

19

What happens if there's a mutation in a somatic cell?

There may be a change in the cell phenotype or disease predisposition in the individual

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