Exam 4 Flashcards
What regulates the eukaryotic cell cycle?
checkpoints and regulators
List positive regulators in the cell cycle
cyclin, CDK
what is cyclin?
positive regulator
proteins that are made and broken and specific times
what is CDK
activates by binding to cyclin(active site exposed)
phosphorylates target proteins to regulate cell cycle
List negative regulators of the cell cycle
Rb
p53
p21
What is Rb and what does it do?
protein that monitors cell size
active and dephosphorylated
binds to transcritopn factor, blocking G1/S transition
What happens to Rb if the cell size increases?
Rb phosphorylates and becomes in active, relasing E2F, allowing cell cycle to continue
What is p53 and what does it do?
negative regualtor
monitors DNA damage
What does p53 do if there is DNA damage in the cell?
stops cell cycle
calls repair enzymes
if doesn’t work, cell death
What is p21 and what does it do?
negative regulator
binds to p53 and inhibits CDK/cyclin
What are tumor suppressors and what do they do?
negative cell cycle regulator
What happens if a tumor supressor is mutated/inhibited?
too many cell divisions and to little cell death-> tumor
What are proto-oncogenes and what do they do?
postive cell cycle regulator
What happens if a proto-oncogene is mutated or inhibited?
too much cell division-> tumor
what is the product of asexual reproduction
clone cells
what is the product of sexual reproduction
genetically different cells
what is fusion of gametes
fertilization
what is the product of germ cells undergoing meiosis
haploid gametes
what does fertilization produce
diploid zygote
what happens in prophase I of meiosis
homologs pair
what happens in prometaphase I of meiosis?
homologs cross over
what happens in metaphase I of meiosis?
kinetichore goes to centromere, lined up at midline independtly
what happens in anaphase I of meiosis?
homologs separate
what happens in telophase I of meiosis
chromosomes decondense and gather at opposite ends
what happens in prohase II of meiosis?
sister chromatids condense
what happens in prometaphse II of meiosis?
nuclear envelopes disappear
spindle fibers engase kinetochore on sister chromatids
what happens in anaphase II of meiosis?
sister chromatids pulled apart by shortened micro tubules
what happens in telophase II of meiosis
chromosomes decondese and go to opposite ends
how does meisos cause genetic diversity?
when homologs cross, they get different outcomes by the pull when theyre separated
what type of cells does mitosis end in?
similar diploids
what type of cells does meiosis end in
different haploids
What did Gregor Mendel work with and why?
garden peas bc they self fertilize
what is the ratio in a monohybrid cross?
3:1
3 is dominant, 1 is recessive
dihybrid cross ratio
9:3:3:1
what is a characteristic?
observable trait
what is a trait
form of a character
what is true breeding
where plants have same variety as crossed
is true breeding heterozygous or homozygous
homozygous
what is mendels law of segration
alleles separate when gametes are made
provide proof of mendels law of segregation
anaphase I of meiosis
what is mendels law of independent assortment
alleles assort independently when gametes are made (because of the separation)
provide proof of mendels law of independent assortment
metaphase I of meisosis, they line up independently
what is independent assortment
assorting on different chromosomes
show an autosomal dominant genotype
AA or Aa
show an autosomal recessive genotype
aa
what is epistasis
where certain alleles mask the effect of other alleles
define genetic linkage
genes on same chrmosome
what is locus
location of gene
what is a gentic map made of
recombination frequencies
anueploidy definition
too many/ too few chromosomes
monosomy
2n-1
trisomy
2n+1
polyploidy
extra set of chromosomes
triploid
3n
tetraploid
4n
deletion
loss of chromosomal segment
dubplication
repeat of chromosomal segment
inversion
180 flip of chromosomal segment
translocation
piece of chromosome moved to another
maternal age effect
older you get, higher risk of abnormal chromosomes
what is the chromosome theory of inheritance
since chromosomes are on genes, inheritance is explained by behavior of chromosome
what is thomas hunt famous for
-geneticist
-helped us understand genetic linkage and chromosome theory of inheritance
what determines genetic linkage
recombinace frequency of less than 50%
what happens if recombinance frequency is 50%
on different chromosomes, assort independently
what happens if recombinance frequency is less than 50%
on same chromosome, has genetic linkage
why would nondisjunction occur?
-if homologs dont separate in anaphase I of meiosis
-if sister chromatids dont separate in anaphase II of meiosis
what n bases are purines?
AG
what n bases are pyrimadines
CT
what do nucleotides consist of?
phosphate groups, nitrogenase bases, deoxyribose
what was griffiths experiment about
transforming principle
what was hershey and chase’s experiment about
genetic material (bacteriophoase)gets injected and allows for modification
what was macleod+mccarthy+avery’s experiment about
dna from strain can genetically transform S cells to R cells
what did watson+crick prove
there are equal amounts of each base and their pair
what is in deoxyribose
sugar, n bases, phosphate groups
whats semi conservative dna replicatio
one exact copy(parental) one new copy
where does replication begin
ori
how many ori do prokaryotes have
1
how many ori do eukaryotes have
multiple
describe the process of dna replication
-unwinds, both become parental
-template
what does topiosomerase do
prevent too much coiling
what does helicase do
unzip
what does primase do
makes up RNA primer
why is primase important
used to make daughter strand
what do single-strand binding proteins do
keep strands open
what is telomerase
RNA that complimets overhang of 3’ end
how is DNA corrected?
proofreading
mismatch repair
how does proof reading work and when
after replication, recognizes and repairs errors
how does mismatch repair work and when
during replication, scans for mismatched bases and repairs
