3.4.2 DNA and Protein Synthesis

Question 1

Describe transcription (7)

Answer 1

1. DNA strands separate by breaking hydrogen bonds;
2. (Only) one of the strands is used as a template (to make mRNA);
3. Complementary base pairing so A to U, T to A, C to G, G to C;
4. (RNA) nucleotides joined by RNA polymerase;
5. Forms phosphodiester bonds
6. Pre-mRNA formed;
7. Splicing/ introns removed to form mRNA

Question 2

Describe translation (7)

Answer 2

1. mRNA binds to ribosome;
2. ribosome moves to start codon/AUG
3. Idea of two codons/binding sites;
4. (Allows) tRNA with anticodons to bind/associate with codon on mRNA;
5. tRNA brings specific amino acid;
6. mRNA moves along to the next codon;
7. (Catalyses) formation of peptide bond between amino acids (held by tRNA molecules);

Question 3

Describe the Role of ribosome (5)

Answer 3

1. mRNA binds to ribosome;
2. Idea of two codons/binding sites;
3. (Allows) tRNA with anticodons to bind/associate;
4. (Catalyses) formation of peptide bond between amino acids (held by tRNA molecules);
5. Moves along (mRNA to the next codon)/translation described

Question 4

Describe Role of tRNA (4)

Answer 4

1. anticodon complementary to codon/reads message on mRNA;
2. specific amino acid;
3. carried/transferred (to ribosome);
4. correct sequence of amino acids along polypeptide;

Question 5

Describe how a phosphodiester bond is formed
between two nucleotides within a DNA molecule.

Answer 5

1. Condensation (reaction)/loss of water;
   2 between phosphate and deoxyribose;
   3 (catalysed by) DNA Polymerase

Question 6

What is a gene

Answer 6

A sequence of DNA nucleotides that codes for a polypeptide;

Question 7

What is The genome

Answer 7

(The) complete set of genes in a cell. OR (All) the DNA in a cell/organism;

Question 8

What is The proteome

Answer 8

(The full) range/number of different proteins that a cell is able to produce (at a given time); OR
(The full) range/number of different proteins the genome/DNA is able to code for;