bio lab exam 2

cancer

disease of cell rapdly dividing when/where they should not in multcellular organisms

cancer caused by

accumulation of mutations

central dogma

DNA → RNA → protein

central dogma explained

genetic info stored in DNA that info transcribed into RNA intermediates then translated into proteins

DNA replication

the process of duplication that occurs every time a cell divides

DNA mutations

often dangerous causing impaired cells, cell death, or cancer

DNA pols

copy DNA templates for normal DNA replication or deal with issues that hinder it

yeast

single celled eukaryotes fungus

yeast are used in research

easy to work with, genes are homologous to humans, single celled eukaryotes

eukaryote chromosomes

have multiple origins of replication

at origin

initiating factors separate 2 DNA strands

helicase

proteins moves along DNA and separates double helix

DNA polymerase

enzyme that synthesizes new DNA and bind at junctions of single/double strands

primase

protein add short RNA primer and acts as a recruitment site for DNA polymerase

leading strand

replicated continuously and synthesized by DNA pol epsilon

lagging strand

synthesized discontinuously by DNA pol delta

both pols 2 enzymatic active sites

1 synthesizes DNA 5’-3’ and 2 proofread 3’-5’

ligase

connects strands after replication

spontaneous

damage caused by normal cellular processes like cellular respirations

induced

damage caused by environmental factors like UV radiation or chemical agents

1 in 10^10

combined errors per nucleotide

DNA damage response

systems designed to deal with DNA damage

DNA repair or DNA damage tolerance

2 ways to deal with DNA damage

DNA repair

properly fixing the broken DNA

DNA damage tolerance

get rids of damage and replace it with random sequence maybe causing many mutations

repair fails

cell death or extreme chromosomal defect

mismatch repair MMR

corrects replication errors made by DNA pols by binding/removing mismatch base so DNA pol can put in correct

accuracy on DNA replication relies on

base selectivity of DNA pols/how accurate they are, proofreading, and MMR

the pols need

normal DNA structure bc cant replicate damage template

TLS

can promote replication past abnormal template with specialized pols

pol zeta

can add base across lesion and extend past creating normal ends for replicating pols but leave many mutations

pol zeta is responsible for

most induced mutations and half spontaneous mutations

CAN1 genes

codes for arginine permease

arginine permease

membrane transport protein that allows arginine in but also toxic canavanine

without canavanine

all cell will grow

with canavanine

wild type cells die but cell with mutations to CAN1 gene survive

level one mutation

already present and not caused by UV

level two mutation

mutations created by UV damage

dilution calculation

total µL/µL of colonies added

cancer cells divide

more than normal cells creating tumors

tumors

can interfere with function of surrounding body tissue

limitless replicative potential, tissue invasion/metastasis, sustained angiogenesis, evading apoptosis, self-sufficiency in growth signals, insensitivity to antigrowth signals

6 hallmarks of cancer

wildtype

no level 1 mutations/everything intact

PMS1

has partial deletion of PMS1 so cant function in MMR to help prevent mutations

PR

has point mutation in pol epsilon proofreading area so can’t proofread and synthesis is faster

DD

2 point mutation that destroy pol zeta activity causing less mutations

survival calc

(# of colonies on UV treated SC plate)/(# of colonies on SC plate with no UV)

spontaneous mutation frequency calc

(# of colonies on UV treated SC+CAN plate)/(# of colonies on SC plate with same UV treatment X dilution factor)

induced mutation frequency

(mutation frequency at UV dose) - (mutation frequency for plate with no UV)

WT had

best survival rates

DD had

worst survival rates and lowest spontaneous mutations

PR/PMS1 had

highest spontaneous and induced mutations

DD/WT

had lowest induced mutagenesis