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

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Original post by tohaaaa
Here are some more questions on B3:

1)Many internal body conditions must be regulated, blood glucose is one of these. Describe how blood glucose is regulated when the levels get too high and too low, in your answer refer to the hormones and organs involved.
2)The kidneys filter the blood. Explain how.
3)Explain the factors that affect transpiration rates in plants.
4)The villi are an example of an exchange surface, describe and explain the features of the villi which make it an effective exchange surface.

AND FINALLY:

5)Ventilation is essential for life, describe the process of ventilation in humans, in your answer state in what part of the body ventilation occurs.

Enjoy :smile:


The villi are adapted for effiencet exchange surface as they have a large surface area which increaes the rate of diffusion and exchange, they also contain micro-villi which further increases the surface area. They have a good blood supply via the capillaries which provides a concentration gradient and keeps the diffused substance moving away, the villi are spherical shape which hence, further increaes the surface area. They are also one cell thick which provides a short diffusion path :cool:
Original post by Captain Anonymous
The kidneys filter blood by filtering all the molecules and compounds in the blood. The useful molecules such as glucsoe , water and ions are reabsorped by selective reabsoption depending on how much of these your body requires. The partially permable membrane makes it possible for the molcules to diffuse into the blood and stop molecules such as protein from escaping as it is too large to be filtered


Careful, it's not all molecules, some are too big such as protein so they don't get filtered
Original post by tohaaaa
Here are some more questions on B3:

1)Many internal body conditions must be regulated, blood glucose is one of these. Describe how blood glucose is regulated when the levels get too high and too low, in your answer refer to the hormones and organs involved.
2)The kidneys filter the blood. Explain how.
3)Explain the factors that affect transpiration rates in plants.
4)The villi are an example of an exchange surface, describe and explain the features of the villi which make it an effective exchange surface.

AND FINALLY:

5)Ventilation is essential for life, describe the process of ventilation in humans, in your answer state in what part of the body ventilation occurs.

Enjoy :smile:


5) Basically - your intercostal muscles contract, which makes your ribs move upwards and outwards, making your diapragm flatten - increasing volume which decreases pressure, hence you breathe in as concentration is less in your lungs than they're in atmospherical conditions. Moreover, you breathe out by your intercostal muscles relxing, this makes your ribs move downwards and inwards, moving the diagragm up - decreasing the volume in your thorax which increaeses pressure - hence your breathe out.
Original post by sneakbo2
Careful, it's not all molecules, some are too big such as protein so they don't get filtered


i did mention that, i couldn't remember what to call them, lol just realised i should've called them substances :colone::colone::colone::colone::colone:
Original post by Captain Anonymous
i did mention that, i couldn't remember what to call them, lol just realised i should've called them substances :colone::colone::colone::colone::colone:


Oh yeah you did haha.

New question, Describe the transpiration stream (6 marks)
Original post by sneakbo2
Oh yeah you did haha.

New question, Describe the transpiration stream (6 marks)


YAAAAY :biggrin:, cba to answer that.. i'll do it in a bit.

Q: explain how the surface being moist enables the lung to be an effeicent exchange surface :colondollar:
Reply 866
Original post by Captain Anonymous
5) Basically - your intercostal muscles contract, which makes your ribs move upwards and outwards, making your diapragm flatten - increasing volume which decreases pressure, hence you breathe in as concentration is less in your lungs than they're in atmospherical conditions. Moreover, you breathe out by your intercostal muscles relxing, this makes your ribs move downwards and inwards, moving the diagragm up - decreasing the volume in your thorax which increaeses pressure - hence your breathe out.


Woo, you ploughed through those like a boss :smile:

Well done.

Just 'cause I'm a bastard, here are some more for you all:

1)An animal cell is placed into a concentrated sugar solution, after a while the cell becomes crenated (crinkled). Explain why.

2)Explain what is meant by the term "active transport".

3)Many people are concerned about Global Warming, describe some of the causes and effects of global warming.

4)An athlete goes for a jog, after a while carbon dioxide starts to build up in their cells. Explain the possible effects a build up of carbon dioxide can have on the athlete's body, were the carbon dioxide not to be exhaled.

5)Describe the path of a de-xoygenated blood molecule as it travels from the cells to the heart to be re-oxygenated, in your answer you should refer to the names of the valves, and their functions.

6)Useful substances are carried within capillaries to your cells, describe the adaptations of the capillaries.

(Similar to above)
7)Describe the adaptations of arteries and veins.

8)Artificial hearts and valves can be implanted into a human in substitute for a real one, evaluate the advantages and disadvantages of having an artificial heart/valve.

9)What is a stent? Describe how stents work.

FINALLY

10)Recently, the human population has experienced a rapid increase. Outline the reasons for this increase, and the problems that it has created.

Enjoy :smile:
Your actually a DEVIL!!!!!!!!!!!!!!!!!!!!!!!! :tongue:
Reply 868
Original post by Captain Anonymous
YAAAAY :biggrin:, cba to answer that.. i'll do it in a bit.

Q: explain how the surface being moist enables the lung to be an effeicent exchange surface :colondollar:


A: The moist surface allows gasses to dissolve into the blood, this allows them to be transported around the body.
Reply 869
Original post by Captain Anonymous
5) Basically - your intercostal muscles contract, which makes your ribs move upwards and outwards, making your diapragm flatten - increasing volume which decreases pressure, hence you breathe in as concentration is less in your lungs than they're in atmospherical conditions. Moreover, you breathe out by your intercostal muscles relxing, this makes your ribs move downwards and inwards, moving the diagragm up - decreasing the volume in your thorax which increaeses pressure - hence your breathe out.


One thing I would mention is that the diaphragm muscles also contract/relax.

Other than that, good answer.
Reply 870
Original post by Captain Anonymous
Your actually a DEVIL!!!!!!!!!!!!!!!!!!!!!!!! :tongue:


Yep :smile: Only trying to help :smile:

By the way, these questions have really helped :smile: Thanks all.
1) think you've done it wrong - it should be dilute? :confused:
2) Active transport is the movement of substances from an area of low concentration, to an area of high concentration which goes against the concentration gradient, it required energy which is provided via respiration through the mitochondria
Original post by Captain Anonymous
YAAAAY :biggrin:, cba to answer that.. i'll do it in a bit.

Q: explain how the surface being moist enables the lung to be an effeicent exchange surface :colondollar:


Hmm, since the moist lining dissolves gases, that breaks them down to even smaller molecules, which means that they can diffuse through the exchange surface in to the blood? :confused:
I have no idea, that's a weird application question I guess
(edited 10 years ago)
Original post by tohaaaa
One thing I would mention is that the diaphragm muscles also contract/relax.

Other than that, good answer.


i did mention that.... well partially :colone:
Reply 874
Original post by Captain Anonymous
The villi are adapted for effiencet exchange surface as they have a large surface area which increaes the rate of diffusion and exchange, they also contain micro-villi which further increases the surface area. They have a good blood supply via the capillaries which provides a concentration gradient and keeps the diffused substance moving away, the villi are spherical shape which hence, further increaes the surface area. They are also one cell thick which provides a short diffusion path :cool:


Good answer, but just 2 things:

- Large surface area gives a GREATER area over which diffusion can occur. (You said this increases the rate, but you didn't really state why).

- You mentioned surface area like 5 times :3. Try and keep it all in one section, rather than spreading it out throughout the answer, it makes it more ordered and logical.
Only doing a few more - global warming will increase temperatures around the world, casue sea levels to rise, change animal distibution patterns, migration patters, loss of biodiversity
Reply 876
Original post by Captain Anonymous
1) think you've done it wrong - it should be dilute? :confused:
2) Active transport is the movement of substances from an area of low concentration, to an area of high concentration which goes against the concentration gradient, it required energy which is provided via respiration through the mitochondria


Nope, if it were dilute, water would move into the cell causing it to swell and burst, a process known as lysis :colone::colone::colone::colone:
Original post by Captain Anonymous
1) think you've done it wrong - it should be dilute? :confused:
2) Active transport is the movement of substances from an area of low concentration, to an area of high concentration which goes against the concentration gradient, it required energy which is provided via respiration through the mitochondria


Nah it's concentrated, due to the low concentration of water molecules,the water inside the cells diffuses out in to the concentrated solution and this loss of water makes them crinkle
Original post by tohaaaa
Good answer, but just 2 things:

- Large surface area gives a GREATER area over which diffusion can occur. (You said this increases the rate, but you didn't really state why).

- You mentioned surface area like 5 times :3. Try and keep it all in one section, rather than spreading it out throughout the answer, it makes it more ordered and logical.


Thanks for the advice man, lol i just start writing and then have a brain rush of all my ideas :colondollar:
Reply 879
Original post by Captain Anonymous
Thanks for the advice man, lol i just start writing and then have a brain rush of all my ideas :colondollar:


No problem, it's just with all of this "Quality of written communication" thing, it's more vital to make your answers structured :smile:

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