Replication, Transcription, Protein Synthesis Flashcards Preview

BCH MEtabolism > Replication, Transcription, Protein Synthesis > Flashcards

Flashcards in Replication, Transcription, Protein Synthesis Deck (25)
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1
Q

DNA polymerase

A

replication

2
Q

RNA polymerase

A

transcription

3
Q

Ribosomes

A

translation

4
Q

Replication

A

semi conservative
half old and half new
continuous and Okazaki fragments
template directed synthesis 5’–>3’

5
Q

Replication Mismatch Repair

A

older strand is methylated
unmarked strand with error is corrected
segment around mutation is excised and replaced by DNA polymerase

6
Q

Transcription

A

template-directed synthesis 5’–>3’

Not continuous like Replication

7
Q

Transcription Initiation Complex

A

multi-protein complex built upstream of Promoter
Transcription factos recognize specific DNA sequences proximal and distal
DNA bends/loops for protein - protein interaction
complex recruits RNA Polymerase II

8
Q

Enhancers/Regulatory sequences

A

bind proteins to attract or block RNA polymerase

9
Q

Promoters

A

binding site for RNA polymerase

start site for transcription

10
Q

Terminator

A

sequence site that causes RNA polymerase to fall off

11
Q

Eukaryotic Transcription complex

A

Core Promoter contains TATA sequence that binds TFs
Proximal elements - bind specific factors
Distal elements - bind TFs, enhancers- activators, hormone response elements
Co-Activation Complex- does not bind to DNA, protein-protein interaction
RNA polymerase II- recruited + disengage cts
complex stays bound during multiple rounds of initiation

12
Q

Bacteria - transcription and translation

A

coupling/linked
both occurs in cytoplasm
protein synthesis begins before gene transcription is completed
very fast gene expression response

13
Q

Genes can be switched on to adapt to new nutrients

Glucose –> Lactose

A

once glucose is depleted
genes for lactose digestion is turned on to use lactose for energy
Diauxic growth
beta-galactodase cleaves lactose –> glucose + galactose

14
Q

Eukaryotes- Transcription and Translation

A

Transcription in Nucleus
mature mRNA transported thru nuclear pores
Translation in cytoplasm
mature mRNA binds Translation factors and Ribosomes

15
Q

Eukaryotes initial RNA transcript is processed

A

5’ end capped m7GpppG
3’ end cleaved and polyadenylated
introns spliced

16
Q

Eukaryotic Translation components

A
"protein synthesis"
energetically costly- GTP /ATP 
mRNA - codon
tRNA- charged with AA, anticodon 
ribosome- catalyzes peptide bond formation
Translation factors -  eIFs
17
Q

Eukaryotic Translation Initiation

A

eIF-GTP recruits
40S binds to mRNA
60S binds now forming 80S ribosome
Met-tRNA binds to P site (AUG)

18
Q

Eukaryotic Translation Elongation

A
eEF1-GTP-tRNA 
A site for second charged tRNA   
peptidyl transfer catalyzed by 28S rRNA unit 
80S ribosome  moves 3nt (1 codon)
1 GTP- hydrolysis for delivery 
1 GTP- translocation 
uncharged tRNA moves over to E site  and P site
opening A site
19
Q

Eukaryotic Translation Termination

A

Release Factors (RFs) recognize stop codon in A site
eRF1 stimulates ribosome to catalyze peptidyl transfer but no AA is present for stop codons
Water - nucleophilic attack => hydrolyzes peptide chain from tRNA and release protein
other RFs causes dissociation translation complex

20
Q

Tetracycline

A

antibiotic
binds to A site of 30S
reversibile

21
Q

Erythromycin

A

antibiotic

blocks peptidyl transferase activity in 50S subunit

22
Q

Chloramphenicol

A

antibiotic
blocks aminoacyl-tRNA binding to 50S
can also inhibit Euk mito translation

23
Q

Streptomycin, Neoycin, Gentamycin

A

antibiotic
bind to 30S subunit
causes codon misreading
nonfunctional proteins

24
Q

Diptheria toxin

A

euk translation toxin
ADP ribosylates eEF2 to block 80S translocation
prevents translocation of peptide chain from A site to P site
uses NAD+

25
Q

Ricin

A

N-glycosidase enzyme that blocks eEF1 and eEF2
removes single adenine base from ribose
inactives 60S subunit by cleaving 28S rRNA