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Official AQA Biology Unit 3 14th May 2013 NEW SPEC

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quick question: does the pulmonary artery transport DEoxygenated blood? or is that wrong...

Yes, whilst a vein normally does this - but because the heart is pumping it at a high pressure towards the lungs it has the structure of an artery

Reply 141

jonathanparkes

Original post by gra_ce

quick question: does the pulmonary artery transport DEoxygenated blood? or is that wrong...

Yes, from the heart to the lungs

Reply 142

sneakbo2

Original post by gra_ce

quick question: does the pulmonary artery transport DEoxygenated blood? or is that wrong...

Thats right :smile:

Aorta carries oxygenated blood.

Reply 143

Quantaˌ

jonathanparkes

I would say that the pancreas produces the glucagon

Completely forgot that! Thanks for reminding me.

Original post by MacDaddi

Remember the stored glycogen is in the liver

Thanks. Remembered that after I wrote it.

So, the current question is

Advantages and disadvantages of biofuels [6]

Reply 144

gra_ce

Original post by Quantaˌ

Completely forgot that! Thanks for reminding me.

Thanks. Remembered that after I wrote it.

So, the current question is

Advantages and disadvantages of biofuels [6]

advantages:

1. sustainable -renewable/uses less fossil fuel
2. low pollution -carbon neutral/most emissions are lower than other fuels

disadvantages:

1. slower to produce -plants have to grow etc.
2. land may have to be deforested to make space for sugar-cane fields
3. transportation costs? (i'm not sure on that one)

i hope this is right! please tell me if i'm wrong

Reply 145

jonathanparkes

Original post by gra_ce

Don't think transportation costs comes into it as normal fuels will also have to be transported, but apart from that I think it's all good

Reply 146

Quantaˌ

Original post by gra_ce

They're all fine about from the transportation one- you need to transport fossil fuels as well.

So, what's your question? You need to give another question if you're answering one.

Reply 147

veniceswan

Do I have to mention the arteries and veins?

Original post by MacDaddi

1. Blood is taken into the Kidney by renal arteries
2. Blood passes through porous filter
3. excess water, urea, glucose and ions pass through a partially permeable membrane by diffusion
4. Some ions, water and glucose are reabsorbed into the blood and pass out through the renal vein
5. excess ions, water and the urea are passed to the bladder as urine

How does a healthy person's body react to low levels of blood sugar [3]

Reply 148

gra_ce

Original post by Quantaˌ

They're all fine about from the transportation one- you need to transport fossil fuels as well. What's your question?

explain how water loss is prevented in a plant (4)

Reply 149

jonathanparkes

Original post by gra_ce

explain how water loss is prevented in a plant (4)

The guard cells will close the stomata if the transpiration rate exceeds the uptake of water through the roots, this can lead to wilting which decreases water loss as the leaves collapse and reduce the surface area to volume ratio

Explain one way global warming can affect the Earth [3]

Reply 150

gra_ce

Original post by MacDaddi

glucagon is released from the pancreas when levels are too low. glucagon causes glycogen in the liver to convert to glucose. glucose is released back in to the blood.
Explain the advantages and disadvantages of artificial blood [4]

Reply 151

Quantaˌ

There's a lot of people answering at the same time. I'll try to merge everything.

Original post by hnb97

Suggest disadvantages and advantages of a patient being treated with an artificial heart [5]

Advantages are no need for immosuppressant drugs, no waiting list and no genetic match. Disadvantages are lack of mobility (battery needs to be carried), clots, size and expense.

Original post by veniceswan

Do I have to mention the arteries and veins?

I don't think so- I've never seen it on the mark scheme.

Original post by gra_ce

explain how water loss is prevented in a plant (4)

Stomata close to reduce water loss by evaporation. The leaves are waxy and have no stomata on the top of the leaf. Wilting can also occur.

Original post by jonathanparkes

Explain one way global warming can affect the Earth [3]

Global warming can cause ice caps and glaciers to melt. This will lead to rising sea levels which will cause floods and destroy many natural habitats.

Original post by gra_ce

Explain the advantages and disadvantages of artificial blood [4]

It depends on what type of artificial blood. But, the advantages include no need to match blood and is always available. The disadvantages include not carrying as much oxygen as real blood and expense.

QUESTION: Explain differences between active transport and diffusion [4]

(edited 10 years ago)

Reply 152

pinkgorilla

Original post by Quantaˌ

There's a lot of people answering at the same time. I'll try to merge everything.

Advantages are no need for immosuppressant drugs, no waiting list and no genetic match. Disadvantages are lack of mobility (battery needs to be carried), clots, size and expense.

I don't think so- I've never seen it on the mark scheme.

Stomata close to reduce water loss by evaporation. The leaves are waxy and have no stomata on the top of the leaf. Wilting can also occur.

Global warming can cause ice caps and glaciers to melt. This will lead to rising sea levels which will cause floods and destroy many natural habitats.

It depends on what type of artificial blood. But, the advantages include no need to match blood and is always available. The disadvantages include not carrying as much oxygen as real blood and expense.

QUESTION: Explain differences between active transport and diffusion [4]

Diffusion is the movement of substances/ions from an area of high concentration to an area of low concentration whereas active transport is the movement of substances against a concentration gradient. This process requires energy whereas diffusion does not.

How is the efficieny of food production increased ?

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Reply 153

jonathanparkes

Original post by pinkgorilla

Always useful to put 'energy from respiration'

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Reply 154

Kill3er

Original post by Quantaˌ

Stomata close to reduce water loss by evaporation. The leaves are waxy and have no stomata on the top of the leaf. Wilting can also occur.

I was taught leaves do have stomata on the top, just not as much as the bottom...

Reply 155

jonathanparkes

Original post by Kill3er

I was taught leaves do have stomata on the top, just not as much as the bottom...

No stomata on the top... Just the waxy cuticle and palisade cells

Reply 156

Kill3er

Original post by jonathanparkes

No stomata on the top... Just the waxy cuticle and palisade cells

Oh, okay then. Just making sure :smile:

Thanks!

Reply 157

Quantaˌ

Original post by pinkgorilla

How is the efficiency of food production increased ?

Next time, please write how many marks a question is otherwise it's hard to know how much detail is needed.

But, efficiency is increased by reducing energy loss (eg. factory farming- less energy in lost in movement and heat so more energy is used for growth) and reducing stages in the food chain (eating plants instead of cows which graze on plants)

Original post by Kill3er

I was taught leaves do have stomata on the top, just not as much as the bottom...

I thought that stomata on the top, at least in land plants, would cause way too much water loss so there are no stomata. Also, most leaves have a waxy cuticle on the top- this would stop gas exchange occurring in the stomata. But I guess it would be safer to say 'there are fewer stomata on the top'. That way you're not wrong either way.

QUESTION: Compare a biogas generator and a mycoprotein fermenter. [2]

(edited 10 years ago)

Reply 158

issie1234

You guys are all so good at answering the questions! I have most of the knowledge but under exam pressure I can hardly string a sentence together :/

Anyway, I'm confused about a few things and I was wondering if someone could explain them?

- can you give me a simple explanation of the whole glycogen/glucagon thing? What releases what from where?

- how does the kidney filter?

- what is the process of ventilation?

- what is the process of producing biogas?

Sorry for being annoying, I'm just a bit overwhelmed!

Thank you :smile:

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Reply 159

jonathanparkes

Original post by issie1234

Glycogen is what the liver stores glucose as when it is not needed/blood glucose levels are too high. The glucose is stimulated to turn into glycogen by the insulin hormone secreted by the pancreas.