AQA BIOL5 ~ 17th June 2013 ~ A2 Biology

I don't mean to be repetitive in asking what questions could come up for the essay, but I'm really struggling. I know someone posted brief plans to about 7 essays earlier which were helpful:
- How structure of cells relate to function
- Control within/of living organisms
- Negative feedback
- Use of ATP
- Use of inorganic ions
- Movement/transport of substances in organisms
- Importance of enzymes

I've noticed that even in those essays listed above, a lot of the content is from Unit 1,2,4 (which I haven't done since the exam in each). Is there a way of identifying "big" topics? (I was thinking to revise respiration in detail but not sure if doing only that is enough) E.g I haven't done anything on gas exchange in fish/lungs etc. for the "movement/transport" Q, nothing on antibodies for the "control of organism" Q... Which topics from unit 1,2,4 are you actually learning in depth to write about in the 25 mark essay?

Oh no! how much did they get wrong? ive literally just printed this paper off to do

are you doing plans for those 7 essays only?

ahah! i had this exact same problem..
basically, you can only sequence a short section of dna, so by splitting it up with restriction endonucleases you can sequence short sections.
by knowing how far apart each RE cuts, you can piece it back together in the correct order which tells you the full sequence.. i think..

Makes sense, cheers!

Does anyone think that vital organs could come up as an essay? We've done loads on that through the whole course, heart, lungs, liver in relation to glucose control and the brain with controlling heart rate and temperature.

Nope, someone was really helpful and posted essay plans to those on roughly page 102 of this thread (apologies for not knowing their account name).

My problem is that I've left it until now to look over synoptic content so I can't decide which parts from unit 1,2,4 I should revise. I'm basically relying on the essay Q being on something I can include mainly unit 5 things in, since I think I'll only have time to cover maybe respiration in detail, then photosynthesis/the nitrogen/carbon cycle,

These are a few essays that i don't think have come up yet so they may this year. I've also thought of a few things to write about.

How the structure of cells is related to their function.
· Prokaryotic bacteria specialised to cause disease and resist antibodies
· White blood cells to kill bacteria
· Alpha and Beta cells and glucose regulation
· Nerve cells to transport action potentials
· Any cell with many mitochondria: Link reaction, Krebs cycle and Electron transport chain
· Epithelial cells for diffusion
· Microvilli in the intestine for absorption
· Red blood cells contain haemoglobin and large surface area
· Muscle cells, actin and myosin for muscle contraction
· Rod and cone cells
· Xylem and phloem in cohesive tension theory

The control of living organisms and control within living organisms.
· Thermoregulation
· Heart rate
· Oestrogen cycles
· Glucose regulation
· Synapses and muscle contraction
· Antibodies
· Absorption of starch
· Diffusion and affinity of haemoglobin
· Tropisms
· Biological and chemical controls of population

Negative Feedback and its importance in biology.
· Return to normal levels
· Thermoregulation
· Heart rate
· The oestrus cycle
· Glucose regulation
· Population control
· Control of ventilation
· Metabolic pathways

The different ways in which organisms use ATP.
· Respiration - Glycolysis
· Photosynthesis – GP to TP
· Muscle contraction
· Protein carriers and active transport
· Cell division
· Energy transfer in the food chain

Inorganic ions include those of sodium, phosphorus and hydrogen. Describe how these and other inorganic ions are used in living organism.
· Nerve impulses (sodium/potassium ions in action potential)
· Fertilisers
· ATP created by phosphorus
· Absorption in the small intestine
· Nitrogen cycle (nitrates and ammonium ions)

The movement of substances within living organisms / transport systems within living organisms
· Protein transport out of cells
· Digestion and absorption
· Haemoglobin – the blood system – the heart
· Gas exchange in lungs
· Nerve system – Pacinian corpuscle
· Diffusion
· Plants (transpiration) cohesion tension theory

Enzymes and their importance in plants and animals
· Structure:
· Polypeptide chain of hydrogen, carbon, oxygen and nitrogen
· Catalysts that lower activation energy
· DNA Polymerase and DNA Helicase
· Amylase, Maltase, Lactase, Sucrase
· RNA Polymerase
· Restriction Endonuclease
· Reverse transcriptase
· DNA ligase
· Effect of competitive and non-competitive inhibition
· Enzymes and the breakdown of ATP

I just remember my teacher explaining that they had put it the wrong way round on a paper, not sure which one just assumed it was that one.


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negged? what?

its a possibility, that would be a nice essay question , if i learnt it.... a question about human body, however what could you include about plant and bacteria

NEGATIVE FEEDBACK. It's simple but I've confused myself can someone please explain it


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Hi guys!
Can somebody help me out on this please?
In the Nelson Thornes AQA A2 biology book, page 254, it says:
The polymerase chain reaction is carried out in three stages:
1. Separation of DNA strand - DNA fragments, primers and DNA polymerase placed in vessel
2. Addition of primers

Why are they adding primers twice?? Could somebody possibly explain it in simple terms?? I'll love you forever!!!
Thanks
xx

Hi guys!
Can somebody help me out on this please?
In the Nelson Thornes AQA A2 biology book, page 254, it says:
The polymerase chain reaction is carried out in three stages:
1. Separation of DNA strand - DNA fragments, primers and DNA polymerase placed in vessel
2. Addition of primers

Why are they adding primers twice?? Could somebody possibly explain it in simple terms?? I'll love you forever!!!
Thanks
xx

Negative feedback occurs when the feedback causes the corrective measures to be turned off. In doing so it returns the system to its normal level.
E.g The Hypothalamus in the brain detects high blood temperature, it then stimulates corrective measures to return the blood temp to normal (Vasodialtion, sweating etc) The normal temp blood returns to the Hypothalamus which detects the blood is a normal temperature, stopping further corrective measures (Negative Feedback)

someone tell me if i'm wrong but they're not actually adding the primers twice, the primers which are already in the sample now 'anneal', ie. they are being added to the DNA fragments as opposed to added to the sample again. you get meh?

Hi guys!
Can somebody help me out on this please?
In the Nelson Thornes AQA A2 biology book, page 254, it says:
The polymerase chain reaction is carried out in three stages:
1. Separation of DNA strand - DNA fragments, primers and DNA polymerase placed in vessel
2. Addition of primers

Why are they adding primers twice?? Could somebody possibly explain it in simple terms?? I'll love you forever!!!
Thanks
xx