S&F; CSF Mutation + Cancer

Question 1

two places in our body that have effects on resulting protein function

Answer 1

1. germ line (passed down to future generations(
2. somatic (during cell division, not whole body, local effects)

Question 2

what are the two types of alterations?

Answer 2

large scale alterations - chromosomal rearrangements
small scale alterations - one or a few nucleotides altered.

Question 3

what are the types of small scale mutations

Answer 3

substitutions; where one base is replaced by another; can have minimal or major effect

insertions/deletions; can have major effect if within coding sequence, can cause a frameshift

Question 4

what are the types of substitution mutations?

Answer 4

silent, missense, nonsense

Question 5

indels types

Answer 5

causes frame shift if 1 or 2
can maintain frame if 3 nt

Question 6

silent mutation

Answer 6

one nucleotide changes, but no effect on the protein

Question 7

missense mutation

Answer 7

effect depends on the residue role - can have a major effect

Question 8

nonsense mutation

Answer 8

produces a stop codon (uag)

Question 9

insertion mutation

Answer 9

frameshift; can cause a stop codon in the middle of the frame

Question 10

deletion mutation

Answer 10

frameshift; can cause top codon + downstream residues –> catastrophic resides

Question 11

3 nucleotide-pair mutation

Answer 11

frame is intact, but one whole codon is gone.
could have some effect or no effect

Question 12

sickle cell anemia

Answer 12

when the surface area is not a good round circle so the haemoglobin is not able to work effectively, therefore the

Question 13

g2 checkpoint

Answer 13

cyclin; a protein that fluctuates throughout the cell cycle
CDK = cyclin dependant kinase (phosphorylates others) that is activated when attached to a cyclin

maturation promoting factor mpf; specific cyclin/cdk complex; key for g2 checkpoint

mpf phosphorylates many other proteins, allows mitosis to commence. fluctuates too because powers cyclin.

Question 14

stop vs go cell signals

Answer 14

stop; keep proliferation in check
go; stimulate cell proliferation

Question 15

what happens if stop/go aren’t working correctly?

Answer 15

uncontrolled cell growth –> tumours

Question 16

how do cancer causing dna mutations arise?

Answer 16

genetic predisposition; in all cells of the body
acquired; locally in one cell initially

**can lead to loss of cell cycle control

Question 17

proto-oncogenes

Answer 17

genes that normally stimulate cell proliferation
–> can go to overexpression (too much accelerator) -> more cell division than appropriate.
e.g. ras and myc

Question 18

tumor suppressor genes

Answer 18

genes that normally keep proliferation in check
–> loss of function (loss of brakes)
increases cell division.

Question 19

how does cancer work

Answer 19

multiple dna changes (multiple mutations required)
- have to sample the tissue itself. mutations are just in one local region, not the whole body.