DNA and RNA Flashcards
people involved with semi conservative dna replication
meselson and stahl
what is semi conservative dna replication
(copying process of dna) half old dna half new dna for each cell
cell cycle
g1-s-g2-m
what is the arrangement of the two polynucleotides in dna
antiparallel
what is the direction of synthesis
5-3
what is helicase
unzips helix (unwinds dna) and breaks hydrogen bonds
DNA polymerase discoverer
kornberg, won nobel prize
describe dna polymerase
(copies the dna): binds and adds complementary nucleotide & repeats (making the strand on opp side) it follow helicase
what are okazaki fragments
a gap on the lagging strand without a phosphodiester bond
what does ligase do
(seals fragments on the lagging strand) creates phosphodiester bind between okazaki fragments
what happens in g1
growing and regular functions
what happens in s of interphase
synthesis, where the replication takes place. 46 to 92 chromosomes
what happens in g2
growth phase, preparing to divide
what are DNA repair proteins
fix mutations in the strand and chops of mutated strand to allow dna polymerase to come and fix it
what is apoptosis
“cell suicide” if dna is damaged, will pick up signal and programs cell death
where does apoptosis take place
mitochondria
mutation
permanent change that passes repair and apoptosis
what are most mutations caused by
random copying mistakes
3 other causes of mutations
radiation, chemicals, infectious agents
how do cells deal with copying mistakes during replication
dna repair, apoptosis
benefits of not having a perfect dna replication system
evolution and variety; adaptation
normal use of apoptosis in the body
shape of organs
if no apoptosis, example of something that could happen
auto-immune disease, brain growing out of head, tumor
what organelle does transcription take place in
nucleus
what does rna polymerase do
copies dna to rna (c-g g-c a-u t-a)
who was involved with transcription
crick
difference of dna and rna polymerase
rna polymerase doesnt need helicase, unwinds by itself
mRNA
(messenger rna) once transcription is complete; carrier of the message to make a protein
what does rna splicing do
cuts of introns from extrons
introns
non-coding regions of a gene
exons
)coding regions of a gene)-code for protein
codon
mRNA that has been spliced- all exons, no introns
where do codons go/stay
leaves nucleus, goes to ribosome
translation
translating the codon into protein
tRNA/anticodon
carries amino acids to the codon& hydrogen bonds 3 bases
rRNA
ribosomal rna, made of rna and protein
large subunit of rRNA
50s, binds amino acids to form a protein
small subunit of rRNA
30s; coordinates bonding between codon and anticodon
where does translation take place
ribosome
what enzyme is involved in transcription
rna polymerase
the dna code for an amino acid consists of a sequence of
3 nitrogen bases taken from 4 possible bases
what makes types of tumors different
the mutations
benign
not invading or damaging surrounding tissue
malignant
locally invasive- only invades and damages surrounding tissue
metastatic
travels to other parts of the body (lymphatic vessel to blood stream)
oncogenes
normally stimulate growth- needed to grow and live by ALL and they tell cells to divide
suppressor genes
normally inhibit/stop growth
repair genes
normally limit mutations, produce proteins that repair DNA
p53
is a DNA repair protein and is mutated in almost every type of cancer
p53 mechanism of action
binds to specific section of introns, grabs RNA polymerase
p53 genes it affects
controls the expression of 2- cant stop a cell from dividing or cant go into apoptosis
WAF
cellular break
PUMA
apoptosis gene
