Translation

Question 1

rRNA and Ribosomes

Answer 1

Place of synthesis of proteins
Binds to mRNA and facilitate binding of mRNA with tRNA

Question 2

Chemical structure of proteins

Answer 2

1. amino acids: building blocks of polypeptides joined by peptide bonds
2. Polypeptides: sequence of many amino acids joined by peptide bonds ( has N-terminal and C- terminal end)
3. protein

Question 3

Sequence of amino acids in polypeptides determines?

Answer 3

3D shape
properties in the cell

Question 4

How many amino acids are there?

Answer 4

20

Question 5

What are the 4 levels of structure of proteins?

Answer 5

1. Primary: amino acid sequence
2. Secondary: folding and twisting of chain
3. Tertiary: 3D structure of a single chain
4. Quaternary: Complex of polypeptide chains in a multisubunit protein

Question 6

Codon

Answer 6

3 letter code with 64 possible sets

Question 7

How many nucleotides for genetic coding for amino acids?

Answer 7

4 U, C,A,G

Question 8

Stop Codon

Answer 8

UAA
UAG
UGA

Question 9

Start Codon

Answer 9

AUG (met)

Question 10

What are the characteristics of Genetic code?

Answer 10

1. Sequence of nucleotides UAGC
2. triplet code
3. continuous
4. non-overlapping
5. universal
6. degenerate: more than 1 codon for each amino acid
7. Start and stop signal
8. Wobble occurs in the anitcodon

Question 11

where does the amino acid attach onto tRNA?

Answer 11

3’ end

Question 12

Codon-anticodon pairing crucial for?

Answer 12

adding amino acid specified by mRNA to the growing polypeptide chain

Question 13

Wobble hypothesis

Answer 13

pairing at the third position is relaxed and can pair with irregular base-pairing rules

Question 14

Where does protein synthesis take place during translation?

Answer 14

On the ribosomes

Question 15

mRNA code is translated in what direction?

Answer 15

5’-3’

Question 16

What direction is a polypeptide assembled?

Answer 16

N-terminus to C-terminus

Question 17

Charge tRNA brings what to where?

Answer 17

Amino acid to ribosome
tRNA binds to amino acid
anticodon of tRNA bind to complementary codon of mRNA
results in specific amino acid sequence

Question 18

What are the 4 stages of protein synthesis?

Answer 18

tRNA charging
Initiation
Elongation
Termination

Question 19

what does tRNA “charged” mean?

Answer 19

has an amino acid attached
aminoacylation-tRNA synthetase
each amino has a specific one

Question 20

Initiation

Answer 20

Small ribosomal subunit attaches to mRNA
Ribosomal subunit moves along mRNA scanning for initiator codon AUG
Large subunit binds to small subunit
protein synthesis begins

Question 21

How many sites can be occupied by tRNA and what are they?

Answer 21

3
E: exit site
P: peptydil site
A: acceptor site

Question 22

Elongation

Answer 22

Charged tRNA enters site A
Peptide bond is formed
Ribosome translocates to next codon

Question 23

Termination

Answer 23

Stop codon is encountered
release factor binds to stop codon
polypeptide is released
components separate