AQA AS BIO Unit 2 OLD SPEC RESIT Tue 7th June (pm) 2016

Thank you and you are very welcome. I believe you will be going through the paper with your teacher tomorrow if I'm not mistaken so maybe get your teacher to look over some of our answers if you and your teacher don't mind? Probably too much of an ask but yeah. Thank you in advance for putting one together.

Couldnt get a paper today. My teachers asked exam invigilators and they wont hand them over due to copyright/security issues

Sorry for disappointment

But guys you should move on and focus on next exam
instead of wasting time worrying about paper you've done.
Thanks

True, we may have lost/won the battle but we haven't won the war yet!
Biol 4 and Biol 5 are the true challenges!

Couldnt get a paper today. My teachers asked exam invigilators and they wont hand them over due to copyright/security issues

Sorry for disappointment

But guys you should move on and focus on next exam
instead of wasting time worrying about paper you've done.
Thanks

That's unfortunate but you are right about not dwelling on this. I guess I'll see you next week haha.

Thanks

From 0 to 10, How you feeling in:

unit 4?
I rate 7

Unit 5?
I rate 4

I don't really know to be honest but definitely not confident enough to just go and sit them as of this moment. What overall grade do you need/ are you aiming for?

And your avatar looks really peculiar, what/who is it? looks like a cabbage haha

Im hoping to get a B overall

The picture of this figure is called Ludovic. In Latin, Ludo means to play and Ovis can mean egg. The egg is a symbol of the potential, genetics, and of the soul. So this controlled victim (as an example of the whole population) is in a state of coma through pharmaceutic drugs and being fed a constant diet of propaganda through the media, becoming conditioned to accept the event.

Ah well I'm sure you will be able to secure a B, and quite possibly higher!

That's quite interesting. Do you think it reflects you or someone you know?

Post me with alternative answers i'm happy to put next to it.
_{Thanks guys for posting your answers and revise for Unit 4 next Thursday! And good luck!}

Unofficial Mark scheme

What is phylogenetic group? [1 mark]
(Groups based on) evolutionary history/relationship

What is species? [2 marks]
Group of similar organisms able to produce fertile offspring
Notice if you put 'produce fertile offspring' = 2 marks

Label the missing order of taxonomy [1 mark]
Phylum, Order, Genus, Species

Draw addition circles and label them [2 marks]
Two circles -1 for each genus then 1 circle inside each of those for the species

Suggest how this related ????? [2 marks]
Nucleotide sequence: Two species (can't remember names of the tigers) have the same nucleotide sequence for part of a gene so they are more closely related species. The other species has a different nucleotide sequence for part of a gene so it is less closely related to the other two species.

What do you call two or more than of polypeptide chains? [1 mark]
Quaternary (structure)

What is the minimum number of DNA bases in alpha-polypeptide (141 amino acids)? [1 mark]
141 amino acids so 141 x 3 = 423

Explain what happened at K in Cell A. [2 marks]
Crossing over (of the chromatids in the homologous pair of chromosomes)
Forms new combination/variety of alleles

The person with Anemia advantage [3 marks]
Haemoglobin has a lower affinity for oxygen at a higher pO2
So haemoglobin readily unloads to respiring tissues for more respiration

Describe how to use temporary mounts [2 marks]
Cut through leaf for cross-sectional area?
Put nail vanish on slide
Put sellotape on specimen (leaf)????

Find the length between F and G? [2 marks]
Use scale bar as shown - 1.6 cm = 50 micrometers so whole length is 6.4cm/1.6cm = 4 then x 50
200 (micrometers)

What is genetic diversity? [1 mark]
total number of different alleles in a population

What is species diversity? [1 mark]
total number of different species in a community

What measurements needed to calculate index of diversity? [2 marks]
(total) number of organisms of each species
(total) number of organisms of all species

Explain how do sewage reach to river come to scientist's findings? [3 marks]
(high density of organisms but low index of diversity)
Sewage is poisonous to most of the organisms?
Most species died due to lack of oxygen/nutrients = Low index diversity;
Fewer food sources?
Only some species adapted to survive and reproduce;
So population increase = high density of organisms;

Name the structure where gases enter and leave in insect. [1 mark]
Spiracles
Could accept phonogenic spelling (e.g spirale, spiricle)

Name the structure that gases brought directly to respiring tissues. [1 mark]
Tracheoles
Could accept phonogenic spelling (e.g tracheaole, trachiole)

Describe how oxygen reaches to respiring cells. [3 marks]
Oxygen enters through spiracles --> trachea --> tracheoles.
Down the diffusion gradient;
Low oxygen concentration in tissues;
Oxygen diffuses down the gradient;

The mesenteric advantage during vigorous exercise [3 marks]
More blood containing more oxygen // Less blood goes to small intestine
More oxygen to respiring tissues
More respiration
More energy released (from ATP) for muscle contraction

Scientists recommend not to exercise vigorously after eating meals. Do Table 6 and Figure 7 support this conclusion? [4 marks]
(YES)
Blood flow increased for at least 15 mins after consumption.
the sample/data was representative;

(NO)
Table 6 regarding the different meals taken did not specify who the subjects were, how many of them there were and if their meal size was consistent.
The figure didn't specify when the volunteers have last had their meals and if they had done the same 'vigorous exercise'.
No data indicating rate at which blood flow decreased etc. only data done on one artery, blood flow to other areas not measured so hard to draw overall conclusion;
One sample;
Volunteers have different volume of blood;

Name of structure of many different cells for different functions in leaf [1 mark]
Organ

Percentage difference [1 mark]
56(%)

Why do some cells ??? abruity 1 and 2? [1 mark]
Some cells were undergoing DNA replication whilst other cells had finished/not started it

Describe the patterns of blood circulation from Kidney and then return back to Kidney [6 marks]
1. Blood exits kidney through renal vein
2. into vena cava into heart
3. pulmonary artery (reoxygenates)
4. pulmonary vein back to heart
5. heart to aorta
6. aorta to renal artery (back to kidney)

Alternative:
Blood in vena cave goes to right atrium;
Right atrium to right ventricle. Then pulmonary artery to lungs to be oxygenated;
Then pulmonary vein to left atrium then to left ventricle;
Then left ventricle pumps it down the aorta;
Renal artery goes back to the kidney;

The scientists followed strict safety guidelines when collecting samples of faeces. Apart from the risk of contamination from e.coli, this was especially important when collecting human faeces. Explain why.
[1 mark]
Bacteria in human faeces more likely to spread and infect other humans than bacteria in animal faeces as strains may be different

Describe and explain one way how have the scientists increased the reliability of their results? [2 marks]
46 farms so large sample size
more representative (results)

Describe how you investigate nicotrigen-resistant bacteria to be identical to other strain of bacteria from birds? [2 marks]
Determine the DNA sequence and compare.

In UK, few animals feed on antibiotics. Suggest why. [4 marks]
Less resistant bacteria survive and reproduce;
Reduced spread of infection;
Prevents horizontal/vertical gene transmission/conjugation;
Fewer animals die due to infection caused by bacteria;

Alternative:
Antibiotic food is much more expensive so not viable for farmers trying to make profits etc.
Other techniques used such as selective breeding

Anyone know if there is a full unofficial ms?