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BIOL4 Biology Unit 4 Exam - 13th June 2011

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ahhhhhh, ive failed, this was my 1st attempt as well and i really need an A! duno what grade ill get but apart from a few questions it was ****..

Reply 1201

empop92

i reckon max grade for an A will be like 52 or something... just think you can lose 25 marks and still get an A.
alot of people sitting the paper will be wanting a C or something and might have found it hard.. people on student room usually want As so cant say we represent general population :P

Reply 1202

riley-92

photosynthesis produces atp in light dependant but uses it in the light independant so i didnt know whether to tick the first box for photosynthesis, in the end i didnt because its overal net production doesnt produce atp, whereas anaerobic & aerobic respiration does

Reply 1203

Black Butler

Original post by andrewcreed

Yeah you'll be fine, I'd be shocked if they marked that wrong. You're clearly still showing the correct knowledge so they should mark it right.

You know that directional or stabilising selection quesiton arent they both wrong - because only one extreme is being disadvantaged. eh?

Reply 1204

Rainbow249

Original post by tehsponge

I know that. :roll: When I saw anaerobic respiration I was thinking of the equation.

Ohhh ok :/ Whats course u doing?

Reply 1205

tehsponge

Original post by riley-92

This is exactly what I hate about these papers. They don't give you enough information about what they're asking. I mean if it had said "Which stages have a net product of ATP" then it would have made so much more sense.

Reply 1206

tehsponge

Original post by Rainbow249

Ohhh ok :/ Whats course u doing?

You mean not doing, after that exam? :awesome:

Was hoping to do Pharmacology at Bath...

Reply 1207

Flux_Pav

Q: using equation above and knowledge of photosyn. and resp. .. bla bla bla

i put that the temperature is high enough for a fast rate of photosynthesis and hence more biomass produced but the temperature is not high enough for resp. rate to be fast, hence leading to greater difference between the two so high net productivity

Q: 1d - humans synthesise more ATP than body mass. why?

i put humans require ATP for everyday processes such as respiration and movement but more ATP is needed for growth

got 4% for hardy weinburg xD

erm advantages of anaerobic digester
- methane not released into atmosphere so no contribution to global warming
- in ponds, accumulation of animal waste will pollute the habitat but this doesnt happen in digester

why cooling system needed?
- if temperature is too high, enzymes in microorganisms denature and so stop producing organic matter

the 4 marks question at the end
-removal of large amount of photosynthesising biomass
-less co2 removed from atmosphere
-burning vegetation means carbohydrates are being combusted leading to CO2 release
-burning vegetation also means less co2 removed

Q: great tits ! - using information above suggest how this reduces breeding

i put, feather mites digest the oil and so make it harder for birds to maintain body temperature. they spend more energy on maintaining body temperature and less energy used in reproduction
(i was guna write - heat loss means birds do not live long enough to survive and so there will be less mating partners available, resulting in low level of breeding)

for the ATP equation - i put ADP + Pi = ATP

fml i didnt tick the box for electron t chain for photosynthesis for some reason

i put directional selection coz the allelic frequency of T is increasing at the expense of the t allelic frquency decreasing. those who don't produce the enzyme die , leading to more dominant alleles dominating the genepool. characteristics are being changed so directional

Reply 1208

Rainbow249

I just ticked it produces ATP in PSS, cos it didnt say anything about net gain or whatever...

Reply 1209

blackberryaddict

Original post by mkb230

What did everyone put for the very last question (6 marks) ? I wrote a whole essay on the light dependent and independent reaction and completely forgot that it was about the Calvin cycle. Do you think I will get any marks for that question? Generally speaking, I thought it was easier than the January paper, I only need/want a C so hopefully it will be about 36 marks for a C.

It was only about the Calvin Cycle because it only asked about how CO2 was used in photosynthesis. So light dependent stuff was unnecessary but you won't lose credit. All about explaining the Calvin Cycle so anything you say about light dependent reaction will gain credit.

Reply 1210

Scarface-Don

Original post by andrewcreed

Breeding a chocolate population is definitely possible. Nothing said chocolate cats had to be used. Black cats could be bred together, if they are heterozygous, any chocolate cat produced must be homozygous. So just keep breeding random black cats together and you eventually get two chocolate homozygous which produce an all chocolate population. So the answer is yes, it is definitely possible. Without doubt.

And it is directional selection. Only one extreme is being acted against (the one which does not produce the enzyme) and therefore must be directional.

I dont think is directional, its stabilising because only a small proportion of the population had the recessive allele that did not produce the enzyme, and these individuals will have a disadvantage so their unlikely to pass on their alleles. Thus the selection favours the average individual of the population that does produce the enzyme. If the recessive allele was beneficial then it may have been directional.

Reply 1211

samzurai

i thought only ETC doenst happen in anerobic so i ticked it takes place in the organelle dude to krebs!! i hate my NT BOOK!

Reply 1212

Rainbow249

Original post by tehsponge

You mean not doing, after that exam? :awesome:

Was hoping to do Pharmacology at Bath...

Aww bless you, you'll be fine! I think the grade boundaries will be low enough for you to get an A :smile:

I'm doing Pharmacy, so we're doing similar courses hahahaa! This ur first exam?

Reply 1213

tehsponge

Really hope the rest of the population, outside of TSR, completely flopped this exam...

Reply 1214

tehsponge

Original post by Rainbow249

Aww bless you, you'll be fine! I think the grade boundaries will be low enough for you to get an A :smile:

I'm doing Pharmacy, so we're doing similar courses hahahaa! This ur first exam?

Yeah, its my first. I doubt it. Its not like I'm going to do better in Bio 5...

Reply 1215

blackberryaddict

Original post by Black Butler

You know that directional or stabilising selection quesiton arent they both wrong - because only one extreme is being disadvantaged. eh?

It's directional selection. In stabilising selection both extremes are acted against, which is not the case here. In directional selection, only one extreme is acted against, which is the case. I can see the arguments people have for stabilising but I'm certain they will want directional for the answer.

Reply 1216

supernova92

That question where it was to do with the digester.. and it asked why it was better to use organic fertiliser, rather than artificial fertiliser? I swear, there wasn't ANY fertiliser added to it... So that confused me a bit.
I put that it was cheaper because it was more readily available...

Reply 1217

FatalError

But directional selection is a shift of the mean which isn't the case here?

Reply 1218

blackberryaddict

Original post by Scarface-Don

It is acting in the direction favouring the normal genotype and therefore is directional. I can see your argument - it isn't a very good question but I'm pretty sure the mark scheme will be looking for directional.