TRANSLATION

Question 1

what is translation

Answer 1

• the assembly of amino acids into polypeptides at the ribosome
• occurs in the cytoplasm

Question 2

where are ribosomes assembled

Answer 2

in th nucleolus from ribosomal RNA and protein

Question 3

describe the structure of ribosomes

Answer 3

• have a large subunit and a small subunit
• with groove between the units for RNA to bind and attach.

Question 4

why is the sequency of amino acids important

Answer 4

1. sequency of amino acids determine the primary structure
2. primary structure determine the tertiary structure which is how proteins fold into a 3D shape
3. tertiary structure allows the protien to function
4. if the tertiary structure is altered the protien can no longer function e.g.if enzyme active site is altered it can no longer function

Question 5

what is the function of tRNA

Answer 5

transfare amino acids to ribosomes for protein sythesis

Question 6

decribe the strucure of tRNA

Answer 6

• tRNA is a single polypeptide chain folded into a hairpin shape
• hydrogen bonds between complementary bases stablises the shape
• tRNA has an anticodon that is complementary to the codon on mRNA
• Three exposed bases to which the right amino acid can attach to.

Question 7

outline the mechanism of translation

Answer 7

1. During translation mRNA enters the groove between small and large subunits.
2. Ribosome is large enough for codons to be side by side
3. First codon is always the same,start codon AUG which codes for methionine
4. Using ATP energy and an enzyme.tRNA with methionine and the anticodon UAC forms hydrogen bond with AUG.
5. second tRNA carrying a second amino acid binds to the second codon on mRNA with its complementary anticodon
6. A peptide bond is formed between adjacent amino acids and this is catalysed by an enzyme present in the small subunit.
7. The ribosome moves along mRNA reading the next codon
8. A third `tRNA brings another amino acid which bonds to form a deptide bond
9. The first tRNA leaves and is able to collect more amino acids
10. Polypeptide chain continues to grow unitl a stop codon is reached

Question 8

what is the role of cyclic AMP

Answer 8

• cyclic AMP is a nucleotude deravitve that activates proteins by changing their 3D shape
• So that their shape is a better complementary molecules