4.2 DNA And Protein Synthesis

Question 1

What is the genome?

Answer 1

Complete set of genes in a cell

Question 2

What is the proteome?

Answer 2

Full range of proteins a cell can produce.

Question 3

Differences between tRNA and mRNA

Answer 3

tRNA:
- Clover shaped
- Has an anti-codon
- Brings a specific amino acid

mRNA:
- Longer
- Linear

Question 4

Describe the process of transcription

Answer 4

• Hydrogen bonds holding DNA together are broken exposing template strand
• Free floating RNA nucleotides line up with template DNA strand according to complementary base pairing (C with G, U with A, A with T).
• Phosphodiester bonds form between the nucleotides in a condensation reaction to form the completed strand of mRNA with RNA polymerase.
• The hydrogen bonds between the two strands of DNA form again and the strands join together.
• Introns are removed for pre-mRNA via splicing and mRNA can leave the nucleus

Question 5

Describe the process of translation

Answer 5

• mRNA binds to a ribosome
• Two codons can fit inside of a ribosome at a time
• A molecule of tRNA binds to the first codon with its complementary anti-codon
• The tRNA brings a specific amino acid
• This happens again with the second codon in the ribosome
• The two amino acids in the ribosome bind to form a peptide bond
• The mRNA moves along the ribosome so one new codon enters and tRNA binds bringing a new amino acid and forms a peptide bond.
• The process repeats until a stop codon is reached.
• A peptide chain has formed (primary protein structure)

Question 6

Does splicing take place in prokaryotes?

Answer 6

No