AQA AS Biology Paper 2 - 6th June 2017

AleenaRahman

Does anyone have any predictions for Paper 2 Biology???

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Reply 1

Anonymous619

Original post by AleenaRahman

Does anyone have any predictions for Paper 2 Biology???

I've got ideas for questions on DNA - transcription/translation
Biological Molecules
Oxygen dissociation curves

Not sure on any other topics but these were not covered on Paper 1

Reply 2

AleenaRahman

Original post by Anonymous619

I've got ideas for questions on DNA - transcription/translation
Biological Molecules
Oxygen dissociation curves

Not sure on any other topics but these were not covered on Paper 1

Thanks, I feel like there will be a lot on biodiversity because nothing like that came up in Paper 1 at all...

Reply 3

franmorrisxxx

Enzymes, Gas exchange, Immunology and Plants nothing on these really came up on paper 1

Reply 4

Abistudyhard

Definitely something related to biodiversity / variation / investigating diversity, gas exchange- maybe fish as that hasn't been for a while and maybe mass movement in plants ?

Reply 5

AleenaRahman

yea, i think plants will definitely come up as nothing on plants came up on paper 1 :smile:

Reply 6

charlie12569

Original post by AleenaRahman

Thanks, I feel like there will be a lot on biodiversity because nothing like that came up in Paper 1 at all...

biodiversity came up in paper 1 but was more to do with the species side of things

Reply 7

username1777591

fish gills / lungs / haemoglobin / xylem and phloem is what I think will come up

Reply 8

brrrigid

Wasn't much on sugars, lipids and proteins so I'm expecting a couple of low mark questions on them.
Fish + insects + lungs along with enzymes, plants, xylem and phloem seem most likely. Possibly something on cell membranes and the fluid mosaic model? And more on immunity + prokaryotes? Some sneaky transcription/translation too maybe.

Reply 9

Abistudyhard

Original post by brrrigid

Quite a lot came up last years paper 2 about pants and adaptations

Reply 10

AleenaRahman

Monoclonal antibodies, immunity and biodiversity will definitely come up

Reply 11

e113g00

Original post by AleenaRahman

Does anyone have any predictions for Paper 2 Biology???

I'm thinking:

Digestion & absorption
Xylem stuff
Protein synthesis
Gas exchange, maybe fish
Immunity

Reply 12

AleenaRahman

Is anyone ready for the exam???

Reply 13

nerdgirl20

Original post by AleenaRahman

Is anyone ready for the exam???

Not at all :frown:

(( exams are killing me rn

Reply 14

Wikia

Original post by AleenaRahman

Is anyone ready for the exam???

no looooool im sat here pretending to be revising when im lowkey eating ice cream and thinking about my life in the future as an ice cream man

Reply 15

brrrigid

Original post by creac080200

could someone please give me a refresher on what we need to know for xylem and phloem i.e. transpiration, diffusion, mesophyll cells etc.??? really desperate

Not sure how much this'll help now, but (if you need more detail ask) :

Mesophyll cells are the main gas exchange surface of leaves. They have a large surface area and exchange gases through pores known as stomata, the opening and closing of which is controlled by guard cells. Depending on whether the plant is xerophytic or not, the stomata can be sunken, protected within the plant or even have a reduced number of themselves to prevent water loss.

Xylem - transports water + aqueous mineral ions from roots to leaves in a process known as transpiration, which relies upon the strong cohesion formed between water molecules and the tension caused by the water evaporating from the leaves.
The rate of transpiration is dependent on several factors which affect the water potential gradient between leaf and atmosphere, most notably:
- light intensity
- temperature
- humidity
- wind

Water can evaporate from a leaf through the stomata when they open, as long as it moves down the water potential gradient.
A potometer can be used to measure the transpiration rate.

Phloem - transports organic substances (sugars) in solution up and down the plant in a process known as translocation. Phloem vessels contain sieve tube plates, the metabolic processes of which are performed by companion cells. Assimilates made at the source are transported to sinks, where the assimilates are used. This creates a concentration gradient between source (high) and sink (low). The mass flow hypothesis suggests how this works:
1. Source - actively transported solutes move from companion cells into sieve tubes, lowing the water potential; water enters the tubes via osmosis and creates high pressure at the source end of the phloem
2. Sink - at sink end, solutes are being removed in order to be used, increasing the water potential; water leaves the tubes by osmosis and creates low pressure at the sink end of the phloem
3. Flow - a pressure gradient is formed from source to sink, pushing the solutes down the sieve tubes towards the sink where they will be used; a higher concentration of solutes = a faster rate of translocation

Evidence for mass flow consists of ringing (removing ring of bark), aphids (sap flows out from where aphids pierce bark), radioactive tracers (carbon 14) and metabolic inhibitors (ATP inhibitor). Objections against mass flow include the range of sinks with varying water potentials the solutes travel to, and the sieve tube plates creating a barrier that would require a lot of pressure for solutes to continue at a reasonable rate.