Session 15: Mutations Flashcards Preview

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Flashcards in Session 15: Mutations Deck (18):
1

What is a mutation?

A change in the DNA sequence

2

A mutation can arise from what?

DNA replication errors made during cell division
Exposure to ionising radiation
Exposure to chemicals
Infection by viruses

3

What is the name given to mutations that occur in the eggs or sperm, affect all cells in the body and can be passed on to offspring?

Germ line mutations

4

What is the name given to a mutation that occurs in a boy cell and is not passed onto offspring

Somatic mutation

5

Why do RNA polymerases not need to proofread like DNA polymerases?

The cell will be making multiple copies of the RNA, it is unlikely to make the same mistake again i exactly the same place
RNAs are quickly degraded so the bad copy will be removed
RNAs are not inherited molecules and won't be passed down from generation to generation (Not as consequential)

6

What is the role of the mitochondria?

To produce energy

7

Mitochondria DNA can suffer from mutations in the germ line or somatic mutations?

Both

8

Germ line mutations in the gene can be what three things?

Substitution
Insertion
Deletion

9

Which gene mutations in the germ line leads to a frame shift?

Insertion and deletion

10

Germ line mutations in the chromosome can result from what?

Structural:
Deletion
Duplication
Inversion
Translocation

Number:
Non-disjunction

11

What is the chromosome and chromatid number at meiosis I?

Chromsomes: 46
Chromatid: 92 (genetic material is doubled)

12

What is the chromosome and chromatid number at meiosis II?

(Both halved)
Chromosome: 23
Chromatid: 46

13

What is the chromosome and chromatid number at the end of Meiosis?

Chromosome: 23
Chromatid: 23

14

Can mitosis produce a chromosomal mutation?

Yes, errors may occur during metaphase when the chromosomes align at the metaphase plate

15

What could happen if there was a mitotic chromosomal mutation in one of the 2 cells at the 2 cells stage or 1 of the 4 cells at the 4 cell stage etc. during early embryogenesis?

Result in a mosaic individual: an individual with two or more populations of cells with different genotypes

16

What are the possible outcomes if a very early embryo was exposed to radiation?

Death/aborted
Teterogenesis
Increased risk of cancer when born

17

What features allow a germ cell mutation to be inheritable?

Not be lethal to the gamete
Not impair gamete function
Not be lethal at fertilisation
Allow the production of a viable adult with normal reproductive capacity

18

Why do primordial germ cells in males only start to differentiate into spermatazoa at puberty?

They are only needed when oocytes are available to fertilise