Protein Synthesis, Modifications and Targeting Flashcards Preview

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Flashcards in Protein Synthesis, Modifications and Targeting Deck (50)
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1

Describe the function of rifamycin

Prevents RNA synthesis, binds to RNA polymerase to block initiation of RNA chains

2

A mutation in tumor suppressor mRNA would cause *****
a) tumorigenesis
b) increase in tumor supressor proteins and decreased tumorigensis

b)

3

Describe the differences between prokaryotic and eukaryotic ribosomes

Prok - 70S, 50S and 30S subunits
Euk - 80S, 60S ad 40S subunits

4

Which of these acts on both prokaryotes and eukaryotes?
a) tetracycline
b) puromycin
c) streptomycin
d) actinomycin D
e) erythromycin

B and D

5

Polyubiquitinated chains target proteins to what two processes

proteasomal degradation
DNA repair

6

How do amyloid fibrils form?

Abnormal prion proteins (PRP*) bump into normal prp proteins and cause conformational change --> PRP* aggregate

7

Describe the function of actinomycin D

Binds DNA and blocks RNA polymerase movement

8

What are lysosomal proteins tagged wtih?

mannose 6 phosphate

9

During initiation of protein synthesis in eukaryotes, initiator tRNA binds to the small ribosomal subunit then moves along the RNA strand searching for what?

AUG (start codon)

10

What is the difference between multi and poly ubiquitylation?

Multi are ubiquitylated at different points, poly have multi ubiquitin chain

11

In mRNA that is incorrectly spliced to have premature stop codon, ____ proteins bind to each _____ and trigger nonsense mediated decay

upf, EJC (exon junction complex)

12

A loss of function mutation in oncogenic miRNAs would cause
a) tumorigenesis
b) increase in tumor supressor proteins and decreased tumorigensis

b)

13

Name five ABX that act on prokaryotes solely

Tetracycline, streptomycin, chloramphenicol, erythromycin, rifamycin

14

Describe the function of tetracycline?

Blocks binding of tRNA to A site

15

Post-translational import occurs for cytosol proteins with what destiny?

- import into organelles: nucleus, mitochondria, chloroplasts or peroxisomes

16

Cotranslational import occurs when newly formed polypeptide is transferred across ___________

ER membrane

17

Phosphate on serine, threonine and tyrosine accomplishes what?

Drives assembly of a protein into larger complexes

18

How does proteasome degrade misfolded proteins

Ubiquitin is cleaved then the protein is moved into the core where ATPases unfold it and it is digested

19

Describe the function of cyclohexamine

Blocks translocation reaction on ribosomes (lrg ribosome does not move over)

20

Post-translational modifications are addition of __________________ to change chemical nature and/or make structural changes

biochemical function groups

21

A mutation on the target section of an oncogenic mRNA may cause ***
a) tumorigenesis
b) increase in tumor supressor proteins and decreased tumorigensis

a) due to expression not being regulated

22

What is the function of tRNA?

interprets the mRNA code during translation

23

Describe the function of chloramphenicol and anisomycin. What is the difference between these two?

blocks peptidyltransferase rxn in ribosomes (no peptide bond formed)

Chloramphenicol only acts on bacteria, whereas anisomycin only acts on eukaryotes

24

In eukaryotes, what occurs to primary RNA transcript to allow translocation from nucleus to cytosol (3)

1) 5' capping
2) RNA splicing of introns
3) 3' polyadenylation

25

Acetyl on lysine

Helps activate genes in chromatin by modifying histones

26

Which of these acts on prokaryotes solely?
a) alpha-amantin
b) cylohexamine
c) anisomycin
d) tetracycline

Tetracycline
- all others act on eukaryotes only

27

If protein folding cannot be fixed by chaperone, what occurs?

Goes to protease pathway

28

What is added to mRNA after they have been completely spliced? (allows "test" round of translation to occur)

Exon junction complexes (EJC)

29

How is miravirsen used in treatement of infection with Hep C virus?

It is an anti-mir-122
Inhibits mir-122 as a complimentary RNA strand

30

Once the initiator tRNA finds the start codon, locks into P site of ribosome, _____ and other initiation factors dissociate, allowing large ribosomal subunit to bind. Aminoacyl tRNA bound to elongation factor _______ then enters free "A" site on ribosome

EIF2, EF-TU