WJEC A-Level Biology Unit 4 (1400U40-1) - 14 June 2024 [Exam Chat]

Ohh I didn't know the gene replaces the ampicillin. I said that because they appeared in the tetracycline plate they are the non-recombinant plasmids.

If this was the 3 marker I said that these bacteria were the recombinant ones that had the plasmid containing the HCG gene ( which replaced the ampicillin resistance gene) so these colonies were missing.

Yh it wasn't really told in the question and it was quite unclear in the diagram. Basically in the diagram it showed a circle with the plasmid and then the tetracycline and ampicillin resistant gene. It then had a label saying site of insertion of HCG gene on the site where the ampicillin resistant gene was located. They appeared on the tetracycline plate because they want to show all the bacteria were resistant to tetracycline so that the missing colonies on the ampicillin could be identified. That question literally sums up the whole paper. It was literally just application of knowledge

Oh so they basically switched it to catch people out? because what I revised was the gene is inserted between the tetracycline which disrupts it, so the colonies would only be resistant to tetracycline if they had taken up non recombinant plasmids

Do you think for the next part of the question they would’ve accepted selection pressures and migration as reasons why not in equilibrium?

Who did immunology?

I did and made many mistakes

I found it hard idk why

The primary and secondary immune was alright, the first part on TB would’ve been alright if I revised more and didn’t really answer the others

What do we predict and A will be out of 90 marks for unit 4

2019 was 47/90 I think according to revise.wales so worst case I would go a couple marks higher but hopefully it is actually lower

Who did immunology?