Protein Synthesis

Question 1

The 2 stages of protein synthesis?

Answer 1

1. Transcription = occurs in nucleus - involves DNA + mRNA
2. Translation = involves mRNA, tRNA and ribosomes

Question 2

What is transcription?

Answer 2

-when polypeptide is required - triplet code of its gene is converted into a molecule of mRNA

Question 3

Steps of transcription

Answer 3

1. Occurs in the nucleus
2. H bonds between complimentary bases break - DNA uncoils - separating 2 strands
3. One of DNA strands is used as a template by RNA polymerase to make mRNA molecule
4. Free nucleotides line up by complimentary base pairing + adjacent nucleotides are joined by PD bonds = single strand of mRNA
5. mRNA moves out of nucleus through a pore - attaches to a ribosome in cytoplasm

Question 4

What happens after transcription?

Answer 4

-translation

Question 5

Steps of translation

Answer 5

1. mRNA attaches to ribosome and transfer RNA collects amino acids form cytoplasm and carries them to ribosome
2. tRNA = single strand with binding site
3. tRNA attaches to mRNA by complementary base pairing
4. Amino acids attached to 2 tRNA molecules join by PP chain - tRNA detach from amino acid
5. Repeated leading to formation of polypeptide chain until stop codon is reached on mRNA = end