# AQA BIOL1 Biology Unit 1 Exam - 16th May 2011 watch

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1. Can anyone help me with this, from Jan 2010

Calculate the ratio of the mass at the start to the mass at the end for the disc
placed in the 0.60 moldm–3 sodium chloride solution.

Start: 23.7 end: 21.9

I know what the answer is, but how'd you get to it? And also, i really don't get ratios full stop, is this always how you'd tackle a ratio question?

The answer is 1.08 and just be taking 21.9 from 23.7, you get 1.8....is that just a coincidence? Or is that what you do with ratio question, take smaller from larger?

Thanks
2. (Original post by reaperguy)
Describe the role of enzymes in the digestion of carbohydrates
3. (Original post by reaperguy)
Describe the role of enzymes in the digestion of carbohydrates
Food is physically broken down by the teeth. The salivary glands produce amylase that breaks down the starch (for example) into maltose. In the stomach the HCL denatures the amylase enzyme, so it can no longer function. The pancreas produces pancreatic juice which contains amylase, which further breaks down the starch into maltose. In the small intestines, an enzyme called maltase breaks down the maltase to glucose which is absorbed by the blood, through the whole co-transporter business with sodium etc??

What is the test for proteins?
4. (Original post by Tericon)
Can anyone help me with this, from Jan 2010

Calculate the ratio of the mass at the start to the mass at the end for the disc
placed in the 0.60 moldm–3 sodium chloride solution.

Start: 23.7 end: 21.9

I know what the answer is, but how'd you get to it? And also, i really don't get ratios full stop, is this always how you'd tackle a ratio question?

The answer is 1.08 and just be taking 21.9 from 23.7, you get 1.8....is that just a coincidence? Or is that what you do with ratio question, take smaller from larger?

Thanks
You divide. to get ratio
5. (Original post by reaperguy)
Why do we use an isotonic solution?
To prevent osmotic processes occurring, so cells do not become flaccid or turgid

How do you test for lipids?
6. does hydrolysis require atp? i know condensation does?
7. (Original post by BeejTheone)
Yeah starch.

I saw it in a paper eariler today.

Salivary amylase is secreted to partially break down the starch into maltose.
Then once the food gets into the duodenum, pancreatic juices contain maltase enzymes which hydrolyse the glycosidic linkages in maltose to for monomers of alpha glucose
8. (Original post by DoaaK)
does hydrolysis require atp? i know condensation does?
No, I dont think so?
9. (Original post by reaperguy)
Yeah starch.

I saw it in a paper eariler today.

Salivary amylase is secreted to partially break down the starch into maltose.
Then once the food gets into the duodenum, pancreatic juices contain maltase enzymes which hydrolyse the glycosidic linkages in maltose to for monomers of alpha glucose
10. (Original post by reaperguy)
Yeah starch.

I saw it in a paper eariler today.

Salivary amylase is secreted to partially break down the starch into maltose.
Then once the food gets into the duodenum, pancreatic juices contain maltase enzymes which hydrolyse the glycosidic linkages in maltose to for monomers of alpha glucose
Ok starch is a carbohydrate i kinda forgot that :P

Amylase;

(Starch) to maltose:
Maltase;
Maltose to glucose;
Hydrolysis;
(Of) glycosidic bond;
11. (Original post by Rickesh)
To prevent osmotic processes occurring, so cells do not become flaccid or turgid

How do you test for lipids?
AHHH you fell into the trap, its ORGANELLES not cells, the dont accept cells.

Test for lipids, emulsion test= ethanol+water = white ppt
12. (Original post by BeejTheone)
Ok starch is a carbohydrate i kinda forgot that :P

Amylase;

(Starch) to maltose:
Maltase;
Maltose to glucose;
Hydrolysis;
(Of) glycosidic bond;
Damn, I would of got 3...forgot the hydrolysis and glycosidic bonds ! oopsy !
13. Ok anyone explain function of Cell membrane, 5 marker!!
14. (Original post by reaperguy)
AHHH you fell into the trap, its ORGANELLES not cells, the dont accept cells.

Test for lipids, emulsion test= ethanol+water = white ppt
arrgghh !! lol Thanks....yepp thats the one !
15. (Original post by Tericon)
Can anyone help me with this, from Jan 2010

Calculate the ratio of the mass at the start to the mass at the end for the disc
placed in the 0.60 moldm–3 sodium chloride solution.

Start: 23.7 end: 21.9

I know what the answer is, but how'd you get to it? And also, i really don't get ratios full stop, is this always how you'd tackle a ratio question?

The answer is 1.08 and just be taking 21.9 from 23.7, you get 1.8....is that just a coincidence? Or is that what you do with ratio question, take smaller from larger?

Thanks
Oh this also boggled my mind but then I realised it was a flipping ratio they were on about! So basically if you look at the two masses and divide them by each other, this should give you 1.08 if you do the others you'll see it works out.
16. (Original post by BeejTheone)
Starch is a carbohydrate...
17. (Original post by BeejTheone)
the distance is about 20um and rate of blood flow is about 200um in 1 second.
Therefore it will flow through there in 0.1 second
Excuse the stupidity, but I still don't understand that, ok, distance is 20....how did you work out rate of blood flow?
18. how do the SAN and AVN control the cardiac cycle?
5 marks
19. (Original post by BeejTheone)
Ok anyone explain function of Cell membrane, 5 marker!!
FIVE?! D:
20. (Original post by BeejTheone)
Ok anyone explain function of Cell membrane, 5 marker!!
Cell membranes prevent large molecules that do not fit through the phospholipid layer, from entering. They also do not allow charged molecules, or molecules that are no lipid soluble. They allow larger molecules such as Sodium to enter through channel proteins, by facilitated diffusion. With the use of ATP molecules that are going against their concentration gradient (low to high) are also allowed to go through the proteins. Gosh i'm really struggling here ! urmm what else is there?

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