AQA AS Biology Unit 1 Unofficial Mark Scheme

I disagree, I've always been taught that smoking and diet are very different things. I personally think that the question was heading towards you talking about specifically diet and atheromas.

I wrote that diet with lots of cholesterol and LDL's can lead to atheroma which is a deposit of these in the endothelium, blood clots, these can travel to the heart and block or semi-block coronary arteries, can lead to myocardial infarction, heart muscle deprived of oxygen and glucose so the muscle can die.

Well, if smoking is a lifestyle choice which is quite like drinking alcohol, so if alcohol can be a dietary choice then smoking can also be a dietary choice, if it does not categorize under that category then what is it classed as?

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;

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 diffusio 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: Body mass; Side effects; Age; Gender; (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 the neg?

Yes, but have you ever tried eating/drinking cigarettes? Or inhaling a burger?
Smoking isn't diet. If the question wanted smoking, it would have said 'how does smoking affect the risk of CHD' or 'how do lifestyle choices affect risk of CHD?'. Diet in this sense refers to the food that people choose to eat.

if for second from last 5marker question 8a i mixed AV and SA node round but put all of the detail needed for the 5 marks in correct order would i get no marks?

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;

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 diffusio 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: Body mass; Side effects; Age; Gender; (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 the neg?

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;

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 diffusio 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: Body mass; Side effects; Age; Gender; (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 the neg?

Nah, you'd prob get ECF, you'd lose 1-2 marks maximum frm my guessing.

if for second from last 5marker question 8a i mixed AV and SA node round but put all of the detail needed for the 5 marks in correct order would i get no marks?

Meh I just added that as an extra after saying an increased amount of cholesterol consumptions effects, but I'll fight for the people who did put that down.
Think of it, you aren't eating a cigarette BUT you are consuming nicotine and as for your last reference point, this is a level they wouldnt be sooo clear to say a question in the, terms, there has to be some ambiguity.

WOW, amazing!! - HOW DID YOU REMEMBER ALL THAT? I think i got 43/60 going by this ^. is that a C or a B grade do you think?

WOW, amazing!! - HOW DID YOU REMEMBER ALL THAT? I think i got 43/60 going by this ^. is that a C or a B grade do you think?

grade boundaries june are usually higher than papers in Jan

Well, if smoking is a lifestyle choice which is quite like drinking alcohol, so if alcohol can be a dietary choice then smoking can also be a dietary choice, if it does not categorize under that category then what is it classed as?

The ambiguity comes in the student having to realise that the question is asking about cholesterol and atheroma and not just diet in general. If the question was going to be straightforward, it would ask 'how does increased cholesterol increase risk of CHD?'.

I think maybe you need to look in a dictionary, diet is specifically defined as food. Cigarettes are not food, they have no nutritional value. It's completely beyond me how you think you can 'fight' that cigarettes are food. Diet was the named factor in this question so writing about anything else won't gain marks.