Translation

Question 1

What do the three letters of bottom of a tRNA represent?

Answer 1

Anticodon loop that will bind to the mRNA codon

Question 2

What bond forms between bases on tRNA?

Answer 2

H-bonds

Question 3

Where does the amino acid attach to tRNA?

Answer 3

The top of the structure

Question 4

What are the two things required for accurate translation?

Answer 4

1. Correct match between tRNA and amino acid

2. Correct match between tRNA anticodon and mRNA codon

Question 5

What is the enzyme used to bind amino acids to tRNA?

Answer 5

Aminoacyl-tRNA synthetase

Question 6

There are only 45 tRNAs but 61 aa-coding codons… Why is this possible?

Answer 6

Wobble

Question 7

What is wobble?

Answer 7

Flexible pairing at thtird base of codon; allows some tRNA to bind to more than one codon

Question 8

What is the first step in translation?

Answer 8

Small subunit connects to the mRNA

Question 9

Describe each site on a ribosome.

Answer 9

A site- a single amino acid attached to tRNA (aminoacyl-tRNA binding site)
P site- polypeptide attached to tRNA is located in this site. Will bond to the amino acid in the A site to build peptide chain (peptidyl-tRNA binding site)
E site- tRNA is released (exit site)

Question 10

What are the four types of RNA?

Answer 10

mRNA- messenger (encodes for protein)
tRNA- transfer (transfer amino acid to growing polypeptide)
rRNA- ribosomal (found in ribosome)
sRNA- small (found in spliceomere and helps remove introns from mRNA)

Question 11

What are the three stages of translation?

Answer 11

1. Initiation
2. Elongation
3. Termination

Question 12

What does the initiator tRNA look for to start translation?

Answer 12

AUG sequence to start binding sequence

Question 13

What are the two steps of initiation?

Answer 13

1. Small ribosomal subunit bind to mRNA

2. Large ribosomal subunit completes the initiation complex

Question 14

What is the name of the complete complex for translation?

Answer 14

Translation initiation complex

Question 15

What are the three steps of elongation?

Answer 15

1. Codon recognition (codon recognized by tRNA)
2. Peptide bond formation (peptide bond formed between new aa)
3. Translocation (shifting of tRNA)

Question 16

What proteins are involved in the adding of new amino acids to the tRNA chain?

Answer 16

Elongation factors

Question 17

What kind of bond is a peptide bond?

Answer 17

Covalent

Question 18

What is the order of movement of tRNA in a ribosome?

Answer 18

A site, P site, E site (unless its a AUG start codon, which begins in the P site)

Question 19

What is the role of elongation factors?

Answer 19

Bring the correct tRNA to the binding site in a ribosome

Question 20

What is the role of a release factor?

Answer 20

Breaking of bonds by the promotion of hydrolysis

Question 21

What does a stop codon cause to occur to the ribosome?

Answer 21

Ribosomal subunits and other components dissociate

Question 22

How are products of translation made functional?

Answer 22

Polypeptides must be folded and sometimes modified

Question 23

What is the purpose of post translation modification?

Answer 23

Alter biological activity or direct to specific locations in cell

Question 24

What are some post-translation modifications that can occur?

Answer 24

1. Change physical shape
2. Chemical modification
3. Addition of molecules/factors
4. Loss of amino acids