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Flashcards in Mutations Deck (27):
1

What is a mutation?

A change in the DNA sequence

2

What do mutations result from?

DNA replication errors made during cell division
Exposure to ionizing radiation
Exposure to chemicals
infection by viruses

3

What is a Germ line mutation?

A mutation that occurs in the egg or sperm, affect all cells in the body and can be passed on to offspring

4

What is a somatic mutation?

occur in a body cell and is not passed on to offspring

5

Why are there more errors in RNA?

RNA polymerase does not proof read like DNA polymerase

6

Why do errors in transcription and translation matter less than errors in genome?

The cell will be making multiple copies of RNA, unlikely to make same mistake in exactly the same place
RNAs are quickly degraded so bad copies will be quickly removed,
Not inherited or permanent

7

What are mitochondria?

Energy producers

8

Where do mitochondrial diseases usually affect?

Heart
Brain
Muscles

9

What problems do people with mitochondrial disease usually suffer from?

muscle weakness, problem with movement, diabetes, kidney failure, heart disease, dementia, hearing loss, vision abnormalities

10

What happens with mitochondrial somatic mutations?

Can not repair themselves so build up over time- raging

11

What must happen for someone to spontaneously get an autosomal recessive disorder?

Mutation of the same gene on both chromosomes at the same time

12

What mutations lead to a frameshift?

Insertions and deletions

13

How can errors at mitosis produce chromosomal mutations?

if chromosomes do not pair correctly at the metaphase plate may cause two copies of the chromosome in one cell and not

14

What does PGC mean?

Primordial Germ cells

15

What are the stages of Oogenesis?

PCG
Oogonia
Some enter prophase- primary oocytes
Primordial Follicle- primary oocyte surrounded by flattened epithelial cells
secondary Oocyte and polar body
ovulation
Egg and polar body

800,000 at birth,
due to apoptosis 40,000 at pubery
500 ovulated

16

What are the stages of Spermatogensis?

PGCs arrive in male gonad and remain there till puberty and form spermatozoa
100 million produced a day
Start at puberty as don't need before

17

What caused most of pregnancy loss?

75% are chromosomal abnormalities e.g. structural and numerical

18

Is mutation rates higher in female or male gametes?

5x higher in male gametes as more divisions and continually active

19

Is IVF embryo aneuploidy rate an under or overestimate?

Overestimate- reason they are there as have problems, no fight for sperm

20

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

death, teratogenesis, cancer when born

21

What features would make a ferm line mutation inheritable?

not be lethal to gamete or impair its function would not be lethal at fertilisation, viable adult with normal capacity

22

In general what so recessive mutations cause?

loss of function

23

In general what do dominant mutations cause?

increased function

24

What might mutations do to drug treatment?

no effect of drug
reduced effect
increased effect
side effects
allergic reactions

25

What is a somatic mutation?

Error in mitosis
Can be genetical or less commonly chromosomal

26

what do somatic mutations cause?

Tumour

27

What causes somatic mutations?

Mutagens, radiation and viruses