Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Trends in MB and BT > Protein Synthesis by mRNA translation > Flashcards

Protein Synthesis by mRNA translation Flashcards

1
Q

In which direction is the polypeptide chain growing?

A

N -> C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What type of amino acids form the core?

A

Neutral, hydrophobic amino acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which amino acids form salt bridges?

A

Acidic bases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which amino acids can form disulfide bridges?

A

Cysteine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Bacterial ribosome

A

70S (50S,16S)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Eukaryotic ribosome

A

80S (60S, 40S)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the function of the large subunit in the ribosome?

A

Peptide bond formation, peptidyl transferase center

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the function of the small subunit in the ribosome?

A

Decoding interaction, find shine-dalgarno seq (bacterial), mRNA binding site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

EF-Tu

A

GTPase, brings the aa-tRNA. Hydrolysis of GTP makes EF-Tu release aa-tRNA in A-site. Also masks amino acid in tRNA so it doesnt react

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

EF-G

A

Guides translocation of ribosome, also GTPase.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is wobble base-pairing

A

Third codon doesnt have to have correct watson-crick pairing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Important sites of tRNA

A

Acceptor arm with exposed 3’ end (CCA) which is the amino acid attachment site
anticodon loop - basepairs to mRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How does charging work?

A

Addition of AMP to tRNA by aatRNA synthase provides the high energy bond needed to create an ester linkage between AMP-tRNA and aa-tRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

aa tRNA synthase

A

Two classes depending which OH (2’ or 3’) they primarily attach aa group to. Has hydrolytic editing as proofreading; incorrect aa moves to editing site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Protein synthesis initiation in bacteria

A

Shine-Dalgarno seq upstream of start codon. IF3 binds to E site in small subunit. IF2, IF1 and GTP binds to A-site, mRNA, f-Met to P-site. IF3 leaves so that large subunit can dock (IF2 in GTP form as signal to large subunit), IF2 hydrolyse and leave with IF1.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

IF1

A

Small initiation factor that help IF2 and 3. Blocks A-site.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

IF2

A

GTPase, looses affinity when in GDP state. Provides energy and works as signal molecule for large subunit to come in. Blocks A-site. Also binds to f-Met-tRNA to help it dock

18
Q

IF3

A

Large, blocks large subunit from binding to 30S initiation complex. Binds to E-site

19
Q

Protein synthesis initiation in eukaryotes

A

preinitiation-complex loops mRNA until it finds start codon, prompting eIF2 to hydrolyze GTP causing some eIFs to disappear. eIF5-GTP binds to A-site, which is signal for large subunit to come in. eIF5 hydrolyze GTP causing all remaining eIFs to leave.

20
Q

Which is the human homolog for IF2 in bacteria?

A

eIF5B

21
Q

Selection in ribosome

A

Small subunit stabilize mRNA+anticodon loop if its the correct pairing, so that EF-Tu is in the correct position to be hydrolyzed, if wrong aa-tRNA just leaves

22
Q

Proof-reading in ribosome

A

tRNA has to be rotated to into peptidyl transferase center. Incorrect tRNAs disappear - only correct base pairing can stand the strain?

23
Q

Explain peptide bond formation

A

NH2 in A site attacks CO in P-site, transferring the entre polypeptide chain to the tRNA in the A-site

24
Q

Peptide release in bacteria

A

RF1 and R2 release peptide from ribosome. RF3 releases RF1-2. RF3 hydrolyses and releases from ribosome.

25
Q

Which is the eukaryotic homolog for RF2

A

eRF1

26
Q

How does RFs work

A

Molecular mimicry, looks like tRNA so can go into A-site.

27
Q

What is ribosome recycling?

A

Removing the empty tRNAs, removing the mRNA and splitting the ribosome into its subunits so that it can participate in another round of protein synthesis. Done by RRF and EF-G.

28
Q

What is the primary determinant of secondary structure in a protein?

A

Hydrogen bonding [between backbone atoms]

29
Q

Aminoacyl-tRNA

A

tRNA covalently attached to aa at the 3’ end of tRNA

30
Q

Chloramphenicol mechanism

A

Inhibits peptidyl transferase by binding to large subunit

31
Q

What are the start and stop codons for protein synthesis?

A

Start: AUG
Stop: UAG

32
Q

Which eukaryotic initiation factor is homologous to bacterial IF3?

A

eIF1A

33
Q

Why is tRNA adenylated in tRNA charging?

A

To add a high energy bond

34
Q

What is special about glycine?

A

Is not chiral; more conformational freedom

35
Q

What is special about proline?

A

Less conformational freedom, cant really participate in secondary structures

36
Q

Which direction is alpha-helixes?

A

Right handed

37
Q

What is a possible way to regulate translation in prokaryotes?

A

High complimentary to 16S RNA (shine-dalgarno seq.), and proper spacing to start codon

38
Q

How is the ribosome recruited to eukaryotic mRNA?

A

It recognizes the 5’ cap

39
Q

How does the polypeptide tunnel limit the conformation of the polypeptide chain?

A

It can only big enough for alpha helix, no beta or tertiary structures

40
Q

What is the GGQ?

A

A motif on class I release factors that stimulate polypeptide release from ribosome.

Trends in MB and BT (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions