Central Dogma

Question 1

Initiation process of translation

Answer 1

1. Small ribosomal subunit binds to the five prime end of the mRNA.
2. The small ribosomal sub unit slides along the mRNA from five prime to three prime direction until it reach the start codon.
3. tRNA with the amino acid methionine binds to the mRNA at the P site of the small ribosomal subunit.
4. Only then, the large ribosomal subunit binds to the complex.

Question 2

Elongation process of translation

Answer 2

1. The next tRNA carrying the correct amino acid will enter the A site of the ribosome.
2. A peptide bond will be formed between the amino acid in the P site, and the one in the A site. This reaction is catalyzed by the enzyme, peptidyl transferase.
3. The ribosome translocate for one codon from five prime to three prime direction. This causes the tRNA carrying methionine to shift from P-site and leave from the E-site. The tRNA in the A site move to the P site. The next tRNA enter the A-site.
4. This cycle repeats until the entire polypeptide has been translated.

Question 3

Termination process of translation

Answer 3

1. When the stop codon is reached, a release factor behind to the mRNA, leasing the polypeptide chain.
2. The complex containing the small and large ribosomal subunit, mRNA, and tRNA dissociates.

Question 4

What does it mean by saying that the mRNA is monocistronic ?

Answer 4

It means that the mRNA can only code for a single protein.

Question 5

The terminology used for saying that mRNA can code for a single protein.

Answer 5

Monocistronic

Question 6

Polycistronic

Answer 6

It means that the mRNA can only code for multiple proteins.

Question 7

The term for saying that the mRNA can only code for multiple proteins.

Answer 7

Polycistronic