[hola_im_liv]

looking at this i think the minimum i can get is 49/60 yayayay

[patrickinator]

(Original post by The Assassin)
Hey everyone. Hope you did well on your tests.

As I haven't seen one being made, I've made a start to one and will add more answers when more people contribute to it. This is obviously unofficial, so the real mark scheme could be pretty different. a ; denotes a different point for each mark.

1)

a) Golgi Appartus (1 mark)

b) Nucleus or Nuclear envelope or Nucleolus; lysomomes; Mitochondria;ER
(2 points for 2 marks)

c) What's the function of the mitochondria?
Produce ATP (for energy)

d) Resolution is highest/greatest; due to shorter wavelength of electrons; can see detailed structures; amoeba are thin so TEM works (2 marks)

2)
Describe investigation A
a) 2 drinks decrease the risk of heart disease; then increase it (as you drink more) (2 marks)
b) Why does the 40-50 age group improve the investigation? Increases reliability because alcohol affects different age groups in different ways (metabolism, etc). (1 mark)
c) Evaluate the claim 'Alcohol is good for you' (3 marks)

Yes - in low consumption;
No - correlation does not mean causation;
may be another factor involved;
drinking more than 2/3 increases the risk of heart disease;
didn't specify what alcohols were so can't be sure on the quantity;

3) a) Describe what causes the diaphragm to change shape
(lungs changed shape) diaphragm contracts and flattens;

b) During these two phases, air moves into the lungs. Describe how the diaphragm allows this. (3 marks)
Diaphagm causes inspiration by contracting;
reducing pressure in the lungs;
air pressure outside greater causing it to flow into the lungs;

c) Diffusion through concentration graident; (2 marks)
through thin endothelium of alveoli;
then through thin endothelium of capillary wall;

4) a) What is a pathogen? A micro-organism that causes disease. (1 mark)
b) Phagocytes may destroy bacteria. Explain how. (4 marks)

Phagocytes attracted by chemicals/recognise the antigens;
Engulf/ingest bacteria;
Remain in vacuole/vesicles/phagosome;
Lyosomoes release (hydrolytic) enzymes/fused with vacuoles;
Pathogen digested/hydrolysed/broken down;

c) Why does the antibody only target the specific antigen? (2? marks)
Specific primary structure/amino acid sequence;
Specific tertiary structure;
Determines binding sites;
Complementary to specific antigens;


5) (Cyanide)

a) Describe what the graph shows. Slows it down up to (a certain point); then, sodium uptake is halted completely; (2 marks)
b) 0.2. The y-axis said concentration remaining, so you had to do 10 - 4 which is 6. Then divide that by 30 to get 0.2
c) Cyanide affects respiration. How did the cyanide affect the sodium uptake? (Controversial too - I looked it up on Wikipedia and apparently it binds to cytochrome c in the mitochondria) (2? marks)

Acts as a competitive inhibitor;
Prevents mitochondria producing ATP for energy;
Energy needed in active transport/sodium-potassium pump/co-transport;
To remove sodium and maintain low concentration;

OR

Less respiration happening;
Therefore glucose not being used up as quickly;
Therefore rate of uptake of glucose slower;
Glucose moves into cell by co-transport with sodium ions;
Therefore slower rate of glucose absorption means a slower rate of sodium ion absorption.

6) Starch/amylase question
a) Describe the test for reducing sugars (3 marks)
Heat;
with Benedicts reagent/solution;
Brick red precipitate will form;

b) Why did solution B contain more than Solution A? Quite controversial. (3 marks)
enzyme breaks down starch into amylose;
reducing water potential in tube;
water moves in via osmosis;


c) The student said that a pH of 8 was the optimum temperature. Is this right? (1 mark)

Didn't test intermediate values (2-8);
Didn't test values above 8;

7) a) Hydrolysis (1 mark)
b) Proteins too large; carrier proteins are specific; carrier proteins may be damaged;
The proteins in membrane are selective; The conc of amino acids in cell is greater than conc of amino acids outside cell; facilitated diffusion involves that involves movement of
large molecules DOWN a conc gradient. Hence why the dipeptide cannot diffuse through. (3 marks)
c) Villi become damaged; reduced surface area; less diffusion;
membrane bound enzymes; reduced breakdown of proteins; less absorption (Once only for less absorption) (3 marks)

d) Why does the gluten stimulate an immune response? (Some lines from the text) + sees it as non-self (1 mark)

e) Factors to consider: Side effects; Cost; Injection/Oral; Overall effectiveness (2 marks)


8) a) How does the heart co-ordinate contraction of the atria and ventricles? (5 marks)

SAN sends out electrical activity/wave of impulses;
Stimulates contraction of atria/initiates heart beat/acts as pacemaker;
AVN delays (electrical impulses);
Allowing atria to fill before ventricles contract/ventricles to fill before
contract;
AVN sends of wave of electrical activity down Bundle of His/Purkyne fibres;
Causing ventricles to contract (from base up) / ventricular systole;

b) How does a diet increase the risk of heart disease? (5 marks)

High consumption of fat/cholestrol accumulate in artery wall/ under lining / endothelium of artery;
Atheroma;
Can cause blood clots/thrombus
May break off;
and get lodged in the coronary artery;
Reduces blood supply;
(so) reduces oxygen supply;
Heart muscle can't respire without oxygen and so dies;
Salt/ions;
can causes high blood pressures;


Why are people negging :L mad because you got things totally different to this?

I want to look at it but I just can't force myself aaaaaaaaaaaaaaaaaaaaaah!

[Maths.Guy]

(Original post by 05jwappleyard)
Sorry, all 3 of u have put similar. I thought when people were saying age, sex etc it didn't sound right

The question said "what factors would need to be considered when giving the drug to people" (or something similar along those lines)

Surely you have to consider the age of the person the drug is being given to? A young child may respond completely different from a middle aged man?

and gender makes sense too? (some women, e.g pregnant women, may have a different reaction to the drug)?

[F1reF0x]

(Original post by The Assassin)
7) a) Hydrolysis (1 mark)


Why are people negging :L mad because you got things totally different to this?

Dunno why people are negging this is really helpful mate cheers
Just one question:

Can you clear this up for me, is the answer to 7B hydrolysis or condensation? Since peptide bonds are made by condensation reaction where H2O is removed, one hydrogen from Amino group of one amino acid and an O-H bond from the carboxylic group of another to form the peptide bond: Not hydrolysis but is condensation.

Well, this is assuming the question was how are peptide bonds formed, not broken. Did the question ask how they were formed or broken?

[jakemarsden]

you no for 7e could you also have put that previous illneses would have to be considered?

[Sadian]

Pathogen - microorganism that's harmful to the body. I said that instead of disease. Would I lose the mark?

[britash]

Lost about 15 marks. (BUT i marked harshly)!!
So probably got *very* similar to my january (45/60)..
Just hope its an A this time and not a B

[The Assassin]

(Original post by britash)
Lost about 15 marks. (BUT i marked harshly)!!
So probably got *very* similar to my january (45/60)..
Just hope its an A this time and not a B

Same. If they're not very generous, I got around 45. I hope that's an A!

[jakemarsden]

on 7e could you also say previous illneses have to be considered?

[The Assassin]

(Original post by F1reF0x)
Dunno why people are negging this is really helpful mate cheers
Just one question:

Can you clear this up for me, is the answer to 7B hydrolysis or condensation? Since peptide bonds are made by condensation reaction where H2O is removed, one hydrogen from Amino group of one amino acid and an O-H bond from the carboxylic group of another to form the peptide bond: Not hydrolysis but is condensation.

Well, this is assuming the question was how are peptide bonds formed, not broken. Did the question ask how they were formed or broken?

Thanks. Unfortunately, it said 'name the chemical reaction of breaking down (or something like that) protein into amino acids' - so it's hydrolysis. =|

[F1reF0x]

Yeah I must have been rushing through the paper. Oops, threw away an easy mark there.

[Project Peace]

what do you think the grade boundaries are???

[oliviajackson01]

for 6b. starch isn't broken down into amalayse. starch is broken down by amalayse, which produces maltose.

[jakemarsden]

on 4b would you have to put the specific enzyme name or could you just say enzymes?

[jakemarsden]

useally about 46=A
42=B
38=C
34=D
30=E
i reckon i got about 45 lets just hope for a leniant mark scheme!

[Mina!SS]

for question 1.b, I put smooth ER and mitochondria.
Do you think that'll still get both marks or did nucleus have to be one of them?

[Scienceisgood]

So, hold on a minute guys;

Do I get ANYTHING in this paper for saying co-transport, facilitated diffusion and lack of glucose uptake for the cyanide Q?!

[nicecookie]

what is a pathogen?

i put bacteria causing disease and initiate an immune respone

do you think i will still get a mark?

[jakemarsden]

isnt the very first question smooth ER? it really looked like it!

[jakemarsden]

science is good you should get a few marks for that