WJEC A2 Biology - BY4 (8th June 2015)

How could you go into an exam being weak at respiration or photosynthesis.....

that's a suicide mission.

Things like, it's used in synthesis, movement (muscle contraction)

Hey all, I realise this is pretty late, I just needed an answer!

In relation to how the orangophosphorus could kill you, what did people put? As the question asked that you explain all the symptoms, it stumped me.

I put that if the orangophosphorus was inhibiting cholinesterase at the synaptic cleft of a cardiac neuromuscular junction, then the heart would fibrillate and cause a heart attack.

However, thinking about it, that can't be correct as the heart is controlled by the AVN and the SAN... I don't know if they're affected by this drug?

A friend of mine touched on the cardiac muscle just as you did and I had the same question.
I said the same thing about theory as you did (inhibition of cholinesterase etc), went on to talk about how there's constant firing of the post synaptic membrane etc.
With regards to symptoms I said that breathing is controlled by the intercostal muscles which would be affected since organophosphorus acts on neuromuscular junctions so breathing would be affected and suffocation may follow. I also said there'd be constant stimulation of muscles so they'd contract over and over which would lead to an oxygen deficiency so anaerobic respiration starts taking place and there's a build up of lactic acid which will eventually lower the pH to the point the cells die.

Yeah that's really helpful mate thank you! It's always comforting to know others have the same ideas after exams! Your breathing explanation was a good'un!

I put aquatic environment (10', human body (37' and underground geothermal areas (probably wrong for 92' how did people answer what the 10' bacteria problems were? I said aquatic environment = less oxygen and too much salt if in sea.

Sorry that not everyone is as excellent as your lordship?
/end sarcasm

This was not needed, I think my point is universally accepted.

Hey, could someone explain to me interms of discontinuous variation whats ment by "characters that are clear cut and easy to tell apart are controlled by a single gene. Eg. Dark and light forms of the peppered moth, the ABO blood grouping system, where the gene has more than two alleles"

Im particularly confused about the having more than two alleles bit!!

Hey, could someone explain to me interms of discontinuous variation whats ment by "characters that are clear cut and easy to tell apart are controlled by a single gene. Eg. Dark and light forms of the peppered moth, the ABO blood grouping system, where the gene has more than two alleles"

Im particularly confused about the having more than two alleles bit!!

Let me rephrase. I meant it in the sense of, get off your high horse. Maybe some people aren't good at respiration, but better at another things?

Does anyone have any by5 predictions ??