2.17 Translation Flashcards Preview

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Flashcards in 2.17 Translation Deck (17):
0

What is the translation Initiation codon

AUG (Methionine)

1

What are the three termination codons

UGA
URG
URA

2

Describe the structure of a tRNA molecule

Clover leaf structure as a result of intramolecule H bonding
70-80 nucleotides long
CCA at 3' terminus

3

What part of tRNA recognizes mRNA

The anitcodon

4

What enzyme binds tRNAs with their appropriate amino acid/

Aminoacyl tRNA Synthetase

5

A ribosome has two subunits. What are they and what is the overall Ribosome structure called?

Ribosome 60s and 40s
Make Ribosome 80s

6

What are the three phases of translation?

Initiation
Elongation
Termination

7

What two things compose the Initiator complex during the initiation phase?

1. Methionyl-initiator tRNA
2. 40s subunit of Ribosome

8

What recognizes Met-tRNA and binds it to 40s ribosomal subunit?

Eukaryotic Initiation factor 2 (eIF2)

9

Initiation in eukaryotes requires at least 10 proteins designated as what?

eIF's

10

The 40s ribosomal unit travels down message until it reaches what codon?

AUG

11

What are the three tRNA-binding sites

P (Peptidyl)
A (Aminoacyl)
E (Exit)

12

What brings the second aminoacyl tRNA to the A site

EF-tu coupled to GTP

GTP is used to catalyze reaction

13

What is the role of EF-T?

It replaces the GDP with a GTP in the EF-Tu complex. This allows for a renewal of use

14

What is the difference between EF-Tu and eIF-2

EF-Tu is the elongation factor
eIF-2 is the initiating factor
-Both use GTP

15

What is the direction of protein synthesis?

N-->C

16

mRNA contains an iron response element near its 5' cap. If iron is scarce, what happens?

A protein called the iron response element-binding protein (IRE-BP) binds to the IRE, blocking translation of mRNA