Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
21 Cards in this Set
- Front
- Back
|
01: basic kinds of mutations on one base pair (3)
|
Changing
Deleting Adding |
|
|
02: Mutations involving categories of bases
|
TRANSITIONS: switch purine for purine, etc
TRANSVERSIONS: switch pyrimadine for purine, etc. WORSE |
|
|
03: What are point mutations? What are the consequences?
|
alter a SINGLE base
Consequences: -Nothing happens -Shuts off a gene -leaky: protein works, but not as well |
|
|
04: What are DNA MICROSATELLITES?
|
short DNA sequences prone to errors
|
|
|
05: are mutations bad or good?
|
most are bad, BUT, it drives evolution
|
|
|
06: Why aren't errors more common?
|
most errors are corrected by PROOFREADING at polymerase
|
|
|
07: Will a point mutation be replicated?
|
YES, but only 1/4 of 2nd generation will have the erronious base
|
|
|
08: What is a mutation involving pairing of the wrong bases?
|
MISMATCH REPAIR: ie A-G pairing
|
|
|
09: How to correct the mismatch repair in E. Coli?
|
MutS: mismatch repair protein
-LOCKS onto DNA, moves down it to correct, stops at bulge of incorrect pairing. -ATP binds, changes its shape -MutL binds to DNA -MutH binds to L, nicks DNA waway from deformation, unwinds it. Polymerase fills in |
|
|
10: How does MutH know which strand to nick?
|
PROKARYOTES: keep the strand that is HEMIMETHYLATED (will be from original strand)
EUKARYOTES: we are not sure. |
|
|
11: What is the AMES test?
|
Simple way to determine if agent is a mutagen/carcinogen
|
|
|
12: How does the AMES test work?
|
take salmonella, grow on minimal media.
mutation found that will make it need HISTIDINE to grow (one base change). BACK REVERSION: changing back to normal. add your chemical, if you see many colonies growing due to back reversion, your chemical is a mutagen |
|
|
13: types of mutations caused by HYDROLYTIC DAMAGE?
|
DEAMINATION: C becomes U
DEPURINATION: cuts off purine base DEAMINATION w/ METHYL: C becomes T |
|
|
14: What can UV light do?
|
form CYCLOBUTANE RING between T-T, causes skipping or deleting during replication.
too much sunlight overloads repair systems. |
|
|
15: What are BASE ANALOGS?1 example?
|
compounds substituting for normal bases.
ie 5-BROMOURACIL: goes to the C formation, binds w/ G |
|
|
16: How can you repair damage by UV light?
|
DNA PHOTOLYASE: binds to DNA in the dark, recognizing dimer caused by UC light.
then light gives it the energy to break the bond |
|
|
17: What can repair methylated bases?
|
METHYLTRANSFERASE: methyl can prevent proper association of bases, so methyl group is taken away
|
|
|
18: What happens to damaged/altered bases?
|
BASE EXCISION: they are removed
|
|
|
19: How does base excision work?
|
GLYCOSYLASE: cuts base at sugar connection.
AP ENDO/EXO NUCLEASES removes sugar+phosphate. POLYMERASE fills in correct base |
|
|
20: What happens if G is oxidized?
|
A is put in across it
FAILSAFE GLYCOLYSASE: takes out the A |
|
|
21: how do you get rid of a whole nucleotide at once?
|
NUCLEOTIDE EXCISION: happens when cell doesn't know which strand is correct.
UVR a, b, c. two a's bind to larger b, binds to DNA @ distortion (looks like mickey hat). c binds to DNA, cuts one strand at random |
