bio304 exam

4 phases of the cell cycle

g1 - first growth

s - synthesis

g2 - second growth

m - mitosis and cytokinesis

3 checkpoints of the cell cycle

g1 checkpoint - restriction

g2 checkpoint - transition

m checkpoint - spindle

how do cyclins switch cdks on and off?

cdks are present in most cells but are inactive alone

when cyclin levels rise, it joins to cdk and turns it on

when cyclin levels fall, it leaves cdk and turns it off

how do cak, ckis, phosphatases, and apc/c fine tune cdks?

cak - phosphorylation activates cdks

ckis - inhibits cdks

phosphatases - turns cdk on

apc/c - shuts down cdks permanently

4 types of repair pathways for dna damage

base excision

nucleotide excision

recombination

mismatch repair

transitions and transversions

transitions - purine is replaced with another purine, or pyrimidine is replaced with another pyrimidine

transversion - purine is replaced with another pyrimidine

what is more likely to occur, transitions or transversions?

transitions

damage - uracil, abasic site, 8-oxoG, or G single strand break

what is the repair pathway?

base excision repair

damage - bulky adducts, UV photoproducts

what is the repair pathway?

nucleotide excision repair

damage - interstrand cross links, double strand breaks

what is the repair pathway?

recombination

damage - ag and tc mismatches

what is the repair pathway?

mismatch repair

2 names of the repair pathways that handle single strand breaks

base excision repair

nucleotide excision repair

2 names of the repair pathways that handle double strand breaks

nonhomologous end joining

homologous recombination

what double break strand repair only loses a few nucleotides?

nhej

why is nhej error prone, but hr is more accurate?

nhej has no matching sequence, so there is no copy for it to check, leading to deletions or insertions

hr has a matching sequence, so the copy that it checks is undamaged

3 classes of transposons and how they relate to retroviruses

dna like transposons

retroviral transposons

nonretroviral transposons

retroviruses are retrotransposons that have acquired genes that allow them to leave one cell to infect another cell

2 types of mobile genetic elements

transposons and site specific genomes

homologous recombination proteins in eukaryotes and prokaryotes

eukaryotes - reca

prokaryotes - rad51

what can start anaphase

checkpoint walls

apc/c switches on

securin destroyed

cohesin cut

stages of mitosis

prophase - chromosomes condense

prometaphase - nuclear envelope breaks down

metaphase - chromosomes line up

anaphase - sister chromatids sep

telophase - nuclear envelope comes back

cytokinesis - cell separates to form 2 daughter cells