Wrong PPQs

Describe 2 differences between DNA in prokaryotic cells and DNA in eukaryotic cells [2]

Any two from the following:

• Prokaryotes have short DNA / eukaryotic DNA is long [1 mark]

• Prokaryotes have circular DNA / eukaryotic DNA is linear [1 mark]

• Prokaryotes have one molecule of DNA/ eukaryotes have more than one [1 mark]

• Prokaryotic DNA is not associated with proteins / eukaryotic DNA are associated with proteins (histones) [1 mark]

• Prokaryotic DNA does not have non-coding DNA/ eukaryotic DNA has introns (non-coding DNA within genes) and non-coding multiple repeats between genes [1 mark]

A gene is a small section of DNA. State what a gene codes for. [1]

Any one from:

• The amino acid sequence of a protein/polypeptide; [1 mark]

• A functional RNA product OR ribosomal RNA (rRNA) OR transfer RNA (tRNA); [1 mark]

Explain why the genetic code is described as being universal. [1]

• In all organisms / DNA, the same triplet codes for the same amino acid [1 mark]

Name the two non-coding regions of eukaryotic nuclear DNA [2]

• Introns [1 mark]

• Multiple repeats [1 mark]

State why it is possible for a gene from one organism to be introduced into and function in a different organism [1]

• The genetic code is universal [1 mark]

Name the structures labelled X, Y and Z in Figure 2 [3]

• X = RNA polymerase; [1 mark]

• Y = DNA; [1 mark]

• Z= mRNA: [1 mark]

Figure 1 below represents a model for the production of a polypeptide.

Name and outline what occurs in:

i) Process 1

ii) Process 2

i) Transcription: [1 mark]

Any two of the following:

• Production of a mRNA molecule that is complementary to a section of DNA; [1 mark]

• It occurs in the nucleus; [1 mark]

• Involves RNA polymerase: [1 mark]

ii) Translation: [1 mark]

Any two of the following:

• Genetic code on the mRNA is converted into a polypeptide chain; [1 mark]

• Occurs in the cytoplasm: [1 mark]

• Requires a ribosome, tRNA and amino acids; [1 mark]