Translation (L4)

define translation

thr process of protein synthesis after transription of DNA to RNA.

what occurs to mRNA?

it’s decoded in a ribosome outside the nucleus.

define codon

a sequence of 3 DNA or RNA nucleotides that code for a specific AA or stop signal.

how many possible combinations can be made from the 4 nucleotides.

64 (4³ = 64)

why does only 61 of the 64 codons represent AAs?

UAA, UAG & UGA are stop signals.

describe the process of translation.

1. mRNA attaches to ribosome

2. 1st tRNA attaches to start codon by complementary base pairing.

3. a 2nd tRNA attaches to next codon on mRNA.

4. AAs on tRNAs joined by a peptide bond, used tRNA leaves

5. ribosome moves to next mRNA codon to continue, creating an AA chain.

6. when stop codon reached, ribosome releases the polypeptide.