Lecture 3 - Translation

Question 1

How do mRNA vaccines work?

Answer 1

mRNA is translated into the spike proteins that aids production of complementary antibodies

Question 2

Who was the first person to synthesise an artificial gene?

Answer 2

Dr Khorana 1968

Question 3

How is the genetic code degenerate?

Answer 3

64 possible combinations of 3 nucleotides only code for 20 amino acids

Question 4

How was the non-overlapping nature of the genetic code discovered?

Answer 4

1. Proflavin is added which led to single base addition causing a frameshift mutation.
2. If two bases were added, mutation still occurred since frameshift occurred.
3. If three bases were added, no mutation occurred proving that three bases codes for one amino acid

Question 5

What are the three stop codons?

Answer 5

UAG UAA UGA

Question 6

What helps amino acids bind to tRNA?

Answer 6

Aminoacyl-tRNA synthetases

Question 7

What are the two parts of a ribosomes structure?

Answer 7

The large subunit containing 49 proteins and 3 RNA molecules and the small sub unit containing 33 proteins and 1 RNA molecule

Question 8

What are the three sites of ribosome?

Answer 8

A-site: Aminoacyl-tRNA site
P-Site: peptidyl-tRNA site
E-site: exit site

Question 9

What is the initiation stage of translation?

Answer 9

1. A translation initiation factor binds to the E site.
2. The Met initiator tRNA (bound to ribosome P-site) looks for AUG codon and binds to the mRNA when found.
3. The large ribosome subunit binds leading to a charge tRNA binding to the A site.
4. Peptide bond forms between the 2

Question 10

What is the elongation stage of translation?

Answer 10

1. Large ribosomal subunit translocates
2. Old tRNA from P site is ejected
3. Small subunit translocates
4. Process repeats

Question 11

What is the termination stage of translation?

Answer 11

1. Stop codon is in the A site
2. Stop factor binds
3. Ribosome dissociates