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# AQA GCSE - Unit 3 (P3,B3,C3) New specification papers. watch

1. (Original post by ThatPerson)
This is a P2 topic, but since I'm sitting the 2 exams together I might as well ask here.

My textbook just says that momentum is a property of a moving object, but what is it? I don't really get how it helps us understand things or what it actually is?
Momentum is difficult to define because, as your textbook says, it's a way in which objects move. It's best to define momentum (p) using the equation:
P=MV, Momentum=Mass*Velocity
momentum is determined by both the mass of the object and how fast it's travelling. The greater the mass, the larger the moment and the greater the velocity, the larger the momentum. It also means that you need to apply more force to an object to get it up to the same momentum.
2. what did you guys get for paper 2s
3. (Original post by Graviton-Pulse)
Yep. Also, water drawn out of cells by osmosis can cause them to shrivel up and die and a lack of respiration would stop many life processes from taking place to keep you alive (for example, your caloric intake is used for respiration to release energy and maintain a constant body temperature)

Myco protein can be used as a meat substitute and is protein made from the fungi fusarium.
the fungus is grown in fermenters using glucose syrup which is obtained by using enzmes to break down maize starch. Oxygen, nitrogen and other minerals are provided since the fungus respire aerobically.
It's also important that other microorganisms don't get into the fermenter and interfere with the reaction because it can produce a different product (or even a harmful batch of myco protein). Thus, the equipment is sterilised using steam and nutrients is also sterilized ( by boiling it).The air supply is also filtered out to remove any air-borne bacteria.

i need to work on biology.
What grades do you currently have in science (for the previous 2 units)?
i have an A in unit 1 for all 3 sciences. I have an A in B2 and an A* in P2 (i haven't done C2 or C3 yet)

"describe the process by which biogas generators produce biogas"

1) Plant/manure/Waste loaded into the inlet of the generator.
2) Microorganism ferment the waste by anaerobic fermentation.
3) Biogas is produced (70% Methane and 30 % CO2) Removed via outlet.
4) Digested material removed via outlet to be used as fertiliser.

Explain the process of transpiration. [3]
4. (Original post by king_revision)

1) Plant/manure/Waste loaded into the inlet of the generator.
2) Microorganism ferment the waste by anaerobic fermentation.
3) Biogas is produced (70% Methane and 30 % CO2) Removed via outlet.
4) Digested material removed via outlet to be used as fertiliser.

Explain the process of transpiration. [3]
The transpiration stream is the movement of water through the plant roots, up the xylem vessels and out of the leaves by evaporation and diffusion. In hot, windy, dry conditions, water diffuses out of cells quickest. When the stomata are open, water evaporates from the under side of the leaf. This draws more water up through xylem vessels to replace it. As a result the root hair cells draw more water up from the soil by osmosis. Water is needed for photosynthesis, to keep the plant turgid (support), as a cooling effect and to transport minerals to the roots, shoots and leaves.

Conditions such as light intensity, temperature, wind movement and humidity can be used in a bubble potometer experiment to determine the rate of transpiration.

"Explain the differences between the 3 main blood vessels - arteries, veins and capillaries" (4)

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5. hi, i was wondering what the advantage and disadvantages were of heart stents, artificial blood and artificial valves.
6. (Original post by John12343212344)
hi, i was wondering what the advantage and disadvantages were of heart stents, artificial blood and artificial valves.
You are not required to know the advantages and disadvantages of stents or artificial valves for the B3 exam.

However, for artificial blood you do need to know the following advantages and disadvantages.

- Does not need to be refrigerated
- Does not contain cells so blood matching isn't necessary

- Expensive
- Contains less oxygen than whole blood
- Some types are insoluble with water so do not mix well with blood
- Negative side effects
7. Sorry to cut to C3 suddenly, but what do we need to know about getting energy from hydrogen in fuel cells and combustion engines? Again, one of those relatively small topics that get me.

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8. (Original post by CD223)
Sorry to cut to C3 suddenly, but what do we need to know about getting energy from hydrogen in fuel cells and combustion engines? Again, one of those relatively small topics that get me.

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urm no not in great detail, it does say in the spec that if questions are in the exam, all infromation will be provided
9. We do need to know about fuel cell and how hydrogen and oxygen are used to produce energy which can be used to provide electricity and energy.
10. (Original post by CD223)
The transpiration stream is the movement of water through the plant roots, up the xylem vessels and out of the leaves by evaporation and diffusion. In hot, windy, dry conditions, water diffuses out of cells quickest. When the stomata are open, water evaporates from the under side of the leaf. This draws more water up through xylem vessels to replace it. As a result the root hair cells draw more water up from the soil by osmosis. Water is needed for photosynthesis, to keep the plant turgid (support), as a cooling effect and to transport minerals to the roots, shoots and leaves.

Conditions such as light intensity, temperature, wind movement and humidity can be used in a bubble potometer experiment to determine the rate of transpiration.

"Explain the differences between the 3 main blood vessels - arteries, veins and capillaries" (4)

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Arteries- Carry blood away from the heart to the organs around the body
- Blood is carried at a high pressure, so muscle needs to be thick.
- Thick layers of muscle for strength and elastic fibres to stretch and spring back
- Smaller lumen
Veins - Carry bloody towards the heart from the organs
- Lower pressure, so larger lumen to flow blood dispute this.
- Valves to keep blood flowing in the right direction
Capillaries - Involved in the exchange of materials at tissues
- Travel close to every cell
- Permeable walls to exchange oxygen and foods (glucose to cells) and take away CO2.
- Thin Walls (one cell thick)- Quicker diffusion
- Narrow, so larger surface area, more diffusion at once.

I struggle a fair bit on the biogas stuff, soo..

What are the advantages of Biogas? [4] - Just state small concise points if possible.
11. (Original post by Joe7)
You are not required to know the advantages and disadvantages of stents or artificial valves for the B3 exam.

However, for artificial blood you do need to know the following advantages and disadvantages.

- Does not need to be refrigerated
- Does not contain cells so blood matching isn't necessary

- Expensive
- Contains less oxygen than whole blood
- Some types are insoluble with water so do not mix well with blood
- Negative side effects
The specification says that we have to "evaluate the use of: artificial hearts, valves and stents", and this is in B3, plus they are in my textbook so I'll list them anyway:

With stents, they keep the artery open, enabling the flow of blood, which keeps the patient alive, however scar tissue can form,so that patient has to take blood-thinners, which have side effects and can be problematic if the patient is injured.

Artificial Hearts:

Pros:
-Not rejected by the immune system because they are artificial
-Keeps the patient alive while waiting for a donor heart (not sure on this one)

Cons:
-The surgery to implant them can lead to bleeding and infections
-The artifical hearts aren't as good as natural ones and they can malfunction/wear out/break.
-Blood doesn't flow through artifical hearts as smoothly, so blood clots could form, which can lead on to strokes; the patient has to take blood thinners to prevent this.

..Well that was good revision.
12. It's blatant that you have the cgp book! Because I know mine in exactly that wording as well.
13. (Original post by tohaaaa)
Hey,

The way I revised (may be different for you).... I get the texbook, FYI I use this: (legendary - I have e-book version if you want me to send it to ya): http://www.waterstones.com/waterston...FXMRtAod728A1g.

I get the textbook, note down the stuff I need to learn in my exercise book. Go away for 10 minutes. Then come back and attempt to re-write all the relevant detail. I might do this once or twice
Omg i have been reading all the previous posts and your questions are soooo helpful! thank you so much

Can you please send me the e book version please?! I would really appreciate it as im struggling with certain topics!
14. (Original post by king_revision)
It's blatant that you have the cgp book! Because I know mine in exactly that wording as well.
Well I learnt from the CGP book....
15. (Original post by Farhan96)

Do you have the e-book?? Can you send me it please
16. (Original post by king_revision)
what did you guys get for paper 2s
99,97,92. You?
17. Hey guys

If anyone has the e-book version for this book http://www.waterstones.com/waterston...&awinaid=85386

then pleaseeee can you send it to me?

Thank you!
18. how long roughly do you think it would take to revise all the material in b3 and c3?
19. (Original post by NightStrider)
99,97,92. You?
You're probably the reason why I got an A in biology.

89, 97, 95
20. (Original post by ARSHKFW)
how long roughly do you think it would take to revise all the material in b3 and c3?
To Learn it all efficiently.

I reckon you could do it all in about 7-9 hours and get an A. But obviously if you want to go for A*, like most of us, you really need to put it in a lot more because the extra 3-4 marks that get you 100 ums usually take about 5 hours extra to pick up if i'm honest.

IT also fluctuates depending on your concentration. I don't really count hour, but just do revision till I knwo all the stuff really well

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