BIOL4 Biology Unit 4 Exam - 13th June 2011

He wanted a population of chocolate cats, so I'm guessing more than just one generation

Unofficial markscheme - This is what my answers were, obviously some might be wrong so do tell if so. I’ll try and remember as much of the paper as I can. some of my question titles might be wrong as i cant remember exactly and my answers in this are in slightly less detail so that i don't take up to0 much space haha

ATP Question
1.Tick Boxes
- I ticked all 3 for ATP production. Only photosynthesis and aerobic respiration were ticked for the organelles and electron transport chain bit.
2. Equation
- ADP + Pi + energy = ATP (you didn't need to put energy so don't worry)
3. Two ways in which ATP is useful
- Easily hydrolysed in a one step reaction so immediate energy source
- Released in small, manageable quantities so can be used quickly
4. why is lots of ATP needed for biological processes
- Needed for glycolysis to produce even more ATP
- muscle contraction in movement
- active transport (eg. nutrients in gut)

Productivity question
1. Why is productivity higher in whichever July?
- photosynthesis is an enzyme controlled reaction. the temperature was higher in july so the enzymes had more kinetic energy and could work at a faster rate. so the rate of photosynthesis was greater.
2. Equation
- Net = gross - respiratory losses
3. Why was net productivity higher in august than july
- photosynthesis is an enzyme controlled reaction. temperature lower in august at 18 degrees so enzymes have less kinetic energy so rate of respiration lower so respiratory losses are fewer, therefore net productivity is greater.
4. What could horse do with extra nutrients?
- if excess proteins were available it could use them for muscle growth due to the increased amount of exercise because more energy has been made available to it.
5. Why is more energy used in march?
-more energy used in maintaining a respiration rate to maintain the horse's body temperature.

Anaerobic respiration Q
1. 2 reasons for not doing in pond
-Methane could escape into atmosphere
- anaerobic bacteria produce toxic waste which would kill other aquatic organisms
2. Why was it cooled?
- if it gets to hot the enzymes would get denatured and the process would stop.
3. What would eutrophication do?
- nitrates stimulate growth of algae
- algal bloom which blocks light reaching to plants below and so kills plant life below as there isn't enough light for them to photosynthesise
- bacteria feed on dead matter using oxygen, so other aquatic organisms cant respire and die.
- anaerobic dudes move in and produce toxic waste and nitrates

Populations Questionnn
1. What is birth rate
- amount of births in a population in 1000 ....
2. Describe data
- higher life expectancy in uk for both females and males (stated values)
- higher life expectancy of females in both uk and sudan (stated values)
3. Reasons
- sudan is an LEDC - poor sanitation, healthcare, diet
- a lot more men are sent to war where the chances of dying are much higher than not going to war...

Cat question
1. what in the above data proves that the allele for white fur is recessive
- Both parents have black fur but produce a white fur offpsring. they both must be heterozygous for black fur.
2. Ratio
- 1:1
3. phenotypes
- I cant remember this but it was fairly simple. think i remember one being black for sure. one chocolate. the last was either cinnamon or black i think.
4. genetic cross
- as long as one parent was 'Bbi' and the other 'bbi' you should have been fine. produced two black offspring, on choco and one cinnamon.
5.why was the number of choco cats not as expected?
- predicting the frequency of alleles for the genotypes in offspring is just an estimate. the offspring are completely random so any of the possible genotypes can be formed every time.
6. breeder wanted cats of just chocolate fur - is this possible?
- yes if you have parents of genotypes 'bb' and 'bb' OR 'bb' and 'bbi' ... as the offspring will all be chocolate guaranteed - this question has caused controversy i know so lets not start the debate on this again haha


I will do the rest in a bit as i need some food

do u have to state values of the sudan and atp i put realses in short bursts also on horse in march i put need energ y to maintain high body temp, i matched most answers apart from chap 8 but most of them i put along the lines of it lol...

you probably don't have to state the values but i did anyway just to make sure i get the marks. yeh maintaining a high temp is probably all good! what were the chapter 8 questions? what do you think you've got overall?


btw im finishing the unoffical markscheme now but i cant remember all of the questions from the mites one.

i remember the first one being about why random data was collected. the second was the conclusion question. 3rd was null hypothesis. 4th was spearmans showed a negative correlation or something? 5th was describe the data on the graph. 6th - does measuring oil gland size increase reliability. 7th - mites eat pathogenic bacteria and fungus, how could this effect breeding? .... have i missed any?

for those last 3 what did you put btw?

for the oil gland reliability bit i said: It would increase reliability because different tits have different sizes of oil gland therefore you are removing this variable? ..... not sure if this is right though?!

also my null hypothesis was: there is no significant statistical difference between number of mites and successful chicks. is this right?

well they told u it was speaqrman rank so i sed no siginifcant correlation!
ranodmly is just to make it more ralible, avoid bias and identify any anomaloies
i probz got o*****ng both oil gland and birds wrong and bacteria pissd bout that

u also had Q bout prob and chance coz it sed signifcant i put prob due to chance is less than 5%?

yeh i put that the probability it was due to chance was less than or equal to 5% .... cos it said it was significant to the 0.05 but didn't say if it was lower or equal to. my exact answer was:

there was a probability of less than or equal to 5% that the change in frequency of the allele was due to chance.... this means we reject our null hypothesis that the frequency will not change between generations.

cos the question before that was asking what hardy weinberg predicts over the 10 generations. i said: that the allele frequency won't change. and in a way this was kind of a null hypothesis to the next question.

fk i put decreases for hardy lol

do you have to state specific values for the data questions?!

also for the 1st ATP questions i said that energy is used in respirtation and heat loss so their needs to be enough sufficient ATP for cell growth?

for the sudan v uk one i said health care and job saftey in sudan was less so more likely to die at working age? war completley blanked my ming?

for the 100% chocolate cats i said no because of mutations and random fusion of gametes so there is never 1005 chance?

i want around 50/75 hope i havent lost 25 marks!!

even if there was random fusion of gametes it still would have got chocolate though using parents of genotypes 'bb' and 'bb' OR 'bb' and 'bbi' surelyyy?

but i agree mututions is a good argument for saying no. although i dunno if it was taking mutations into account seen as though the whole question was about inheritance of specific alleles. maybe though.

even if there was random fusion of gametes it still would have got chocolate though using parents of genotypes 'bb' and 'bb' OR 'bb' and 'bbi' surelyyy?

but i agree mututions is a good argument for saying no. although i dunno if it was taking mutations into account seen as though the whole question was about inheritance of specific alleles. maybe though.

I swear the question said something like, "The breeder expected to obtain half black and half chocolate offspring, why in practise is this not always the case"?

So random fusion of gametes should be a correct answer.

Also what did you put down for 8b) about how atmospheric CO2 concentrations change? I put it increased due to direct burning of the trees leading to CO2 being released into the atmosphere and less uptake of CO2 from photosynthesis. I can't think of the other mark?

I swear the question said something like, "The breeder expected to obtain half black and half chocolate offspring, why in practise is this not always the case"?

So random fusion of gametes should be a correct answer.

Also what did you put down for 8b) about how atmospheric CO2 concentrations change? I put it increased due to direct burning of the trees leading to CO2 being released into the atmosphere and less uptake of CO2 from photosynthesis. I can't think of the other mark?