Exam 5 Flashcards
describe the process of transcription
info from dna sequence is transcribed to rna
components: initiation, elongation, and termination
what is initiation in prokaryotes
sigma factor binds to promoter, transcription factors bind for initiation.
what is initiation in eukaryotes
transcription factors recognize promoter, RNA polymerase II binds, form transcription initiation complex
what is translation
ribosomes read info from mrna to make amino acid chain (polypeptide)
what bonds are between polypeptides
peptide bonds
describe mRNA structure and role
nucleotide sequence that translates to amino acid sequence by the use of ribosome
what does rRNA do
make up ribosomes
what does tRNA do
carries amino acid and base pairs with mRNA
describe the P site of ribosome
first subunit of tRNA binds
describe A site of ribosome
2nd codon of tRNA enters ribsomes A site
describe E site of ribosome
tRNA exits
What happens in elongation of transcription
RNA polymerase moves along template and is synthesised 5’-3’
what happens in termination in transcription in prokaryotes
mRNA strand released and read by ribosome
what happens in termination in transcription in eukaryotes
pre-mRNA spliced into mature mRNA
what happens in splicing?
introns are removed, only exons
this is also called RNA processing
what does the 5’ cap do in termination
facilitates translation initian and prevent degradation of mRNA
what does the poly A tail do in termination in transcription
stabilizes mRNA export and prevents degradation
name the start codon
AUG
name the 3 stop codons
UAA UAG UGA
describe translation
initiation, elongation, termination
non-ambiguous
degenerate(
describe degeneracy in translation
each sequence only codes for 1 type of amino acid
what happens during initiation of translation
ribosomes attach to mRNA by tRNA
what happens during elongation of translation
Remaining goes to A site
what happens in termination of tranlation
stop codon goes to A site, complex removes in E site, amino acid chain is free
how many promoters do eukaryotes have
multiple
how many promoters do prokaryotes have
1
how many gene regulators do eukaryotes have
1
how many gene regulators do prokaryotes have
multipel
what transcription factor positively regulates transcription
lac operon
which transcription factor negatively regulates transcription
trp
how many structural genes are in the lac operon
3
name the structural genes in the lac operon
lac Z, lac Y, and lac A
what does lac Z do
code for betagalactosidase, hydrolyzes lactose in galactose and glucose
what does lac Y do
codes for beta galactosides, moves lactose in to cell
what does lac A do
transforms actyl group into beta galactoside
what does lac I do
code for repgressor gene
is the lac operon usually off or on
off
is the lac operon catabolic or anabolic
catabolic
is the lac operon inducible or repressible, why?
indicuible because it’s usually turned off
what does the lac operon do
break down lactose
what does the trp operon do
make tryptophan
is the trp operon usually off or on
on
is the trp operon catabolic or anabolic
anabolic
what is epigenetic control
regulates access to eukaryotic genes
is the trp operon repressible or inducible, why?
repressible bc its usually on
what do acetyl groups do for histones?
bind to the tail, allow DNA to be transcibable
what is euchromatin
transcribable histone proteins, loose
what is heterochromatin
intranscribable DNA, condensed, dark
what is alternative splicing
different exon combos
what is mRNA degraded by
microRNA
how are proteins degraded
proteosomes
what does molecular cloning produce
recombinant DNA
how does molecular cloning work
DNA insterted into plasma vector into a bacteria
what is in a plasma vector
-orgin of replication
-selectable marker
-restriction site for cloning
what are expression vectors used for
used to increases transgenes protein product
how does gene therapy work
vector used to deliver a gene to treat, prevent, or cure a disease
