PROTEIN SYNTHESIS

what are proteins made of?

chains of amino acids

why do enzymes have a specific active site?

depends on the folding up of the amino acid chain

define codon

sequence of 3 bases

define amino acid

coded for by a codon

how many possible codons?

4×4×4=64

how many amino acids are there?

20

define non-coding DNA

DNA that doesn’t code for an amino acid

why does protein synthesis need mRNA?

DNA is to large to move out of the nucleus

what is the enzyme involved in joining together the base sequence to make mRNA?

RNA polymerase

describe process of transcription: (6)

• in nucleus

• 2 DNA strands unzip

• RNA polymerase moves along one strand as the template strand

• free mRNA bases complementary base pair with the bases on the template strand

• mRNA is made

• the mRNA molecule moves out of the nucleus

describe the process of translation: (5)

• the mRNA molecule is brought to a ribosome

• tRNA molecules bring anticodons complementary to the codons on the mRNA strand

• tRNA brings the amino acid

• the amino acids join up and fold to form a peptide

• long chains of peptides form proteins