[Picture~Perfect]

Hi all

Here is a link to the paper which I've scanned and added to my skydive.
https://skydrive.live.com/redir?resi...D4F043877A!200
Be warned it can take a while to load, just be patient

My version of the Mark scheme can be found in the second post

If you use this, I would appreciate some positive reputation. I actually put in a fair bit of time and effort to make this available for you.

[Picture~Perfect]

I'm going to attempt an unofficial mark scheme, but I'll need your help

Thanks to JimmyK, ChocolatePearl and sydney07 for your help

Question 1:
(a) (i) TGCTAC (ii) UGC
(b)
(c) It could change the shape of the toxin molecule
(d) Since acetylcholinesterase is inhibited; the acetylcholine diffuses across synaptic cleft, and binds to receptors, triggering an action potential, since no acetylcholinesterase is released the acetylcholine is not broken down; action potentials are continually given off; muscles controlling breathing continually contract; hence can't breath

Question 2:
(a) (i) Shortens (ii) Stays the same
(b) 3046
(c) Myosin head are bound to a molecule of ATP, during contraction this is hydrolysed releasing a large amount of energy. Myosin bind to actin forming cross-bridges and uses the energy to move, pulling along the actin. When the myosin heads detach form the actin another molecule of ATP binds to them. For a strong contraction this action is repeated. If insufficient ATP is provided, this process can not continue, resulting in weaker contractions.

Question 3:
(a)
(i) A short time after the concentration of oestrogen begins to rise, the contraction of LH rises
(ii) There is a fall in the concentrate of progesterone at the end of her cycle

(b)
(i) Progesterone uses negative feedback to inhibit the production of FSH
FSH stimulates the growth of follicles which produce eggs. If the follicles do not grow then eggs are not produced and released. Eggs are never produced as progesterone is continually released. If there is no egg it cannot be fertilised.
(ii) Progesterone is released automatically.

Question 4:
(a) Increased intensity of exercise leads to increased respiration which results in an increase in the concentration of carbon dioxide in the blood. This is detected by chemoreceptors in the aortic arch and carotid bodies. These send nervous impulses to the cardioregulatory accelerator centre in the medulla oblongata. This sends impulses to the SAN centre via the sympathetic nervous system. The SAN stimulates and increase in heart rate.

(b) (i) To act as a control, to allow comparison
(ii) Error bars don't overlap so the results are not due to change (less than 0.05)
All the results of the change in mean heart rate are negative numbers.
Positive Correlation
Quantitative analysis (numbers mentioned?)

Question 5:
(a) Restriction endonuclease
(b) (i) It is a fluorescent gene marker. We will be able to see if the insertion/transformation is successful because a fluorescent protein will be produced as well, therefore we can identify which are successful.
(ii) We do not want the Factor IX gene to be expressed in every cell in the sheep's body but just in the milk. In the mammary glands, milk related genes will be expressed because a transcriptional factor binds with their promotor genes. Therefore it will bind to this promotor gene too and the Factor IX gene will be expressed in the milk.
(c) (i) Immune system detects it being foreign and attacks it?
(ii) So the process is adjusted accordingly and mistakes are not repeated again/same mistake avoided occurring twice.

Question 6:
(a) Adrenaline binds to liver cell receptors which activate enzymes inside the cell, which activate more enzymes which increase glycogenolysis (breakdown of glycogen to glucose) and gluconeogenesis (breakdown of fats and amino acids to glucose), which cause blood glucose to rise. (Second messenger model).

(b)
(i) If fed glucose would be absorbed and cause an increased reading before insulin could act.
(ii) Type ll diabetes is caused by a lack of sensitive to insulin, increasing the amount of insulin may have little or no effect.
(iii) Artificial Gene only needs to be inserted once/no other __necessary
Artificial Gene work for a long time
Only tried on rats, may pose dangers in Humans
Long term side-affects of Artificial Gene not known

Question 7:
(a) To prevent them responding to light/showing phototaxis, to ensure that they are responding to gravity only.
(b) The root tip is needed to produce curvature/sense gravity/produce hormone.
(c) (i) IAA produced in tip diffuses down shoot but moves to the upper side, showing negetive geotaxis. IAA causes cells to elongate, so cells on the upper side elongate causing the root to curve downwards towards gravity.
(ii) IAA produced in the part of the tip that remains, but less than if the full tip was there. It cannot at first move to the upper side until after the cut then does so, causing the same downwards curve. Causes less curving because less IAA is produced and it has less time to act.

Question 8:
(a)
(i) Not sure if enough points Yes there is correlation, the more CAG repeats the younger the person is when symptoms appear. However there is too large a range particularly with lower repeats. For example with 39 repeats the age could be between 25 and 70. Above 50 repeats there is not enough data to be conclusive.
(ii) Often symptoms don't appear until after the sufferer has had children and passed on the genes. In the graph it can be seen that it often doesn't present symptoms until after 50 years, and presumably some people wouldn't have genetic screening.
(b)
(i) K. Because it has travelled the shortest distance so is the longest fragment and contains the highest number of CAG repeats.
(ii) Compared them to fragments of known length (DNA ladder).
(iii) It may have travelled further than the others and dropped off the end of the gel. Or maybe it's the same size as the other one so appears as one band?

Question 9:
(a) ((22.9-18)/22.9)*100 = 21.4%
(b)
(i) To allow for perspiration/panting. Water evapourating from skin/mouth allows heat to leave the blood by convection and the core body temperature to fall.
(ii) Food intake increases because metabolic rate increases. Increased respiration produces more heat to increase body temperature, and this requires increased amounts of food/glucose/substrate.

(c) Milk production decreases because metabolic rate/respiration decreases so less ATP is available for secreting milk or synthesising milk proteins.

(d) Skin is exposed to environmental conditions, heat will be lost by conduction/convection/radiation. Rectal temperature more accurate because more insulated.

(e) A Bull is chosen with a relatively low core body temperature/ that doesn't suffer from Heat Stress

(f) Countries have different numbers of people so using percentages allows for comparison between countries

(g) Sorry to any lactose intolerant people :P In past dairy was very small part of diet so not producing much lactase wasn't an issue. Today due to transportation and refridgeration lactase makes up a much larger proportion of our diet. Therefore people who are lactose intolerant are at an evolutionary disadvantage because if they eat dairy products they become ill. Perhaps they do not have as many children or may be more likely to die as a child, so over time a larger proportion of genes passed on will be from lactose tolerant people and more of the population will become so. This is directional selection. This will happen faster in a country that eats more dairy products because lactose intolerant people will be at more of a disadvantage.

Question 10:
Essay question

[Patchey1000]

(Original post by Picture~Perfect)
I'm going to attempt an unofficial mark scheme, but I'll need your help

Question 1:
(a) (i) TGCTAC (ii) TGC
(b)
(c)

UGC it RNA

[JimmyK]

I'll post what I think the answers are starting at the end working backwards if someone else goes forwards . Edit: Right I'll stop there, someone else can do Q1-4 .

5a) Restriction endonuclease.

5bi) It is a fluorescent gene marker. We will be able to see if the insertion/transformation is successful because a fluorescent protein will be produced as well, therefore we can identify which are successful.

5bii) We do not want the Factor IX gene to be expressed in every cell in the sheep's body but just in the milk. In the mammary glands, milk related genes will be expressed because a transcriptional factor binds with their promotor genes. Therefore it will bind to this promotor gene too and the Factor IX gene will be expressed in the milk.

5ci) not sure Important genes are disrupted by the insertion of new DNA and therefore the embyro cannot develop?

5cii) So that other scientists do not repeat exactly the same method and cause more suffering than is necessary? Other scientists may be able to work out a better way from reading the report?

6a) Adrenaline binds to liver cell receptors which activate enzymes inside the cell, which activate more enzymes which increase glycogenolysis (breakdown of glycogen to glucose) and gluconeogenesis (breakdown of fats and amino acids to glucose), which cause blood glucose to rise. (Second messenger model).

6bi) If fed glucose would be absorbed and cause an increased reading before insulin could act.

6bii) not sure Because rats with type II already have the correct gene but it is not being expressed, or not enough insulin is produced.

6biii) what else? Would require injections every 8 months rather than every day so that would be good. Would probably save the NHS a lot of money, with less people needing insulin and less people being admitted to hospital with hyper/hypoglycaemia, needing paramedics, less surgery etc. Some people may have ethical issues with supplementing their genes. If the viruses were mistakenly not harmless the person would become ill, although this is trivial really.

7a) To prevent them responding to light/showing phototaxis, to ensure that they are responding to gravity only.

7b) The root tip is needed to produce curvature/sense gravity/produce hormone.

7ci) IAA produced in tip diffuses down shoot but moves to the lower side, showing geotaxis. IAA inhibits elongation in roots, so cells on the lower side are shorter causing the root to curve downwards towards gravity.

7cii) IAA produced in the part of the tip that remains, but less than if the full tip was there. Causes less curving because less IAA is produced.

8ai) Not sure if enough points Yes there is correlation, the more CAG repeats the younger the person is when symptoms appear. However there is too large a range particularly with lower repeats. For example with 39 repeats the age could be between 25 and 70. Above 50 repeats there is not enough data to be conclusive.

8aii) Often symptoms don't appear until after the sufferer has had children and passed on the genes. In the graph it can be seen that it often doesn't present symptoms until after 50 years, and presumably some people wouldn't have genetic screening.

8bi) K. Because it has travelled the shortest distance so is the longest fragment and contains the highest number of CAG repeats.

8bii) Compared them to fragments of known length (DNA ladder).

8biii) It may have travelled further than the others and dropped off the end of the gel. Or maybe it's the same size as the other one so appears as one band?

9a) ((22.9-18)/22.9)*100 = 21.4%

9bi) To allow for perspiration/panting. Water evapourating from skin/mouth allows heat to leave the blood by convection and the core body temperature to fall.

9bii) Food intake increases because metabolic rate increases. Increased respiration produces more heat to increase body temperature, and this requires increased amounts of food/glucose/substrate.

9c) Milk production decreases because metabolic rate/respiration decreases so less ATP is available for secreting milk or synthesising milk proteins.

9d) Skin is exposed to environmental conditions, heat will be lost by conduction/convection/radiation. Rectal temperature more accurate because more insulated.

9e) not sure Choose a bull that's mother had a high milk yield?

9f) not sure Countries have different numbers of people so using percentages allows for comparison between countries.

9g) Sorry to any lactose intolerant people :P In past dairy was very small part of diet so not producing much lactase wasn't an issue. Today due to transportation and refridgeration lactase makes up a much larger proportion of our diet. Therefore people who are lactose intolerant are at an evolutionary disadvantage because if they eat dairy products they become ill. Perhaps they do not have as many children or may be more likely to die as a child, so over time a larger proportion of genes passed on will be from lactose tolerant people and more of the population will become so. This is directional selection. This will happen faster in a country that eats more dairy products because lactose intolerant people will be at more of a disadvantage.

[Picture~Perfect]

(Original post by JimmyK)
I'll post what I think the answers are starting at the end working backwards if someone else goes forwards

Thanks I'll work forwards as best as I can

[amazon123456789]

for 1b i wrote dna has introns and mrna doest and ci) hydrogen bonds form in the wrong place

[ChocolatePearl]

3a) ii- Progesterone released.

3b) ii- Oral contraceptive can be broken down by enzymes/acidic conditions in the stomach (not sure about this point) OR Implanon only has to be taken once and work for a long period where as Oral contraceptives have to be consumed several times.

4b) i- Placebo, to compare results and ensure only Omega-3 fatty acids cause the change in mean heart rate.

4b) ii- Error bars don't overlap so the results are not due to change (less than 0.05)
All the results of the change in mean heart rate are negative numbers.
Positive Correlation
Quantitative analysis (numbers mentioned?)

5a) Endonuclease/Restriction Enzyme

5b) Gene Marker?

5c) i- Immune system detects it being foreign and attacks it?

5c) ii- So the process is adjusted accordingly and mistakes are not repeated again/same mistake avoided occurring twice.

6b) iii- Artificial Gene only needs to be inserted once/no other __necessary
Artificial Gene work for a long time
Only tried on rats, may pose dangers in Humans
Long term side-affects of Artificial Gene not known

9e) A Bull is chosen with a relatively low core body temperature/ that doesn't suffer from Heat Stress

[Picture~Perfect]

(Original post by ChocolatePearl)
3a) ii- Progesterone released.

3b) ii- Oral contraceptive can be broken down by enzymes/acidic conditions in the stomach (not sure about this point) OR Implanon only has to be taken once and work for a long period where as Oral contraceptives have to be consumed several times.

4b) i- Placebo, to compare results and ensure only Omega-3 fatty acids cause the change in mean heart rate.

4b) ii- Error bars don't overlap so the results are not due to change (less than 0.05)
All the results of the change in mean heart rate are negative numbers.
Positive Correlation
Quantitative analysis (numbers mentioned?)

5a) Endonuclease/Restriction Enzyme

5b) Gene Marker?

5c) i- Immune system detects it being foreign and attacks it?

5c) ii- So the process is adjusted accordingly and mistakes are not repeated again/same mistake avoided occurring twice.

6b) iii- Artificial Gene only needs to be inserted once/no other __necessary
Artificial Gene work for a long time
Only tried on rats, may pose dangers in Humans
Long term side-affects of Artificial Gene not known

9e) A Bull is chosen with a relatively low core body temperature/ that doesn't suffer from Heat Stress

Thanks for your help

[Akbar2k7]

(Original post by ChocolatePearl)
3a) ii- Progesterone released.

3b) ii- Oral contraceptive can be broken down by enzymes/acidic conditions in the stomach (not sure about this point) OR Implanon only has to be taken once and work for a long period where as Oral contraceptives have to be consumed several times.

4b) i- Placebo, to compare results and ensure only Omega-3 fatty acids cause the change in mean heart rate.

4b) ii- Error bars don't overlap so the results are not due to change (less than 0.05)
All the results of the change in mean heart rate are negative numbers.
Positive Correlation
Quantitative analysis (numbers mentioned?)

5a) Endonuclease/Restriction Enzyme

5b) Gene Marker?

5c) i- Immune system detects it being foreign and attacks it?

5c) ii- So the process is adjusted accordingly and mistakes are not repeated again/same mistake avoided occurring twice.

6b) iii- Artificial Gene only needs to be inserted once/no other __necessary
Artificial Gene work for a long time
Only tried on rats, may pose dangers in Humans
Long term side-affects of Artificial Gene not known

9e) A Bull is chosen with a relatively low core body temperature/ that doesn't suffer from Heat Stress

you mean control

and what about a bull whose mother produced a lot of milk her alleles would increase mile production in his female offspring.

I could sit he

[sydney07]

1d) Since acetylcholinesterase is inhibited; the acetylcholine diffuses across synaptic cleft, and binds to receptors, triggering an action potential, since no acetylcholinesterase is released the acetylcholine is not broken down; action potentials are continually given off; muscles controlling breathing continually contract; hence can't breath

[Picture~Perfect]

(Original post by sydney07)
1d) Since acetylcholinesterase is inhibited; the acetylcholine diffuses across synaptic cleft, and binds to receptors, triggering an action potential, since no acetylcholinesterase is released the acetylcholine is not broken down; action potentials are continually given off; muscles controlling breathing continually contract; hence can't breath

Thanks for summarising that

[EffKayy]

For 1C i think the answer is that the primary structure changes, as the base sequence changes. So the teritary structure changes also.

[holahola]

was one b becuase of introns

[holahola]

1c maybe change in amino aicd sequence therefore different tertiary structure

[alan-93]

(Original post by Picture~Perfect)
I'm going to attempt an unofficial mark scheme, but I'll need your help

Thanks to JimmyK, ChocolatePearl and sydney07 for your help

Question 1:
(a) (i) TGCTAC (ii) UGC
(b)
(c) It could change the shape of the toxin molecule
(d) Since acetylcholinesterase is inhibited; the acetylcholine diffuses across synaptic cleft, and binds to receptors, triggering an action potential, since no acetylcholinesterase is released the acetylcholine is not broken down; action potentials are continually given off; muscles controlling breathing continually contract; hence can't breath

Question 2:
(a) (i) Shortens (ii) Stays the same
(b) 3046
(c) Myosin head are bound to a molecule of ATP, during contraction this is hydrolysed releasing a large amount of energy. Myosin bind to actin forming cross-bridges and uses the energy to move, pulling along the actin. When the myosin heads detach form the actin another molecule of ATP binds to them. For a strong contraction this action is repeated. If insufficient ATP is provided, this process can not continue, resulting in weaker contractions.

Question 3:
(a)
(i) A short time after the concentration of oestrogen begins to rise, the contraction of LH rises
(ii) There is a fall in the concentrate of progesterone at the end of her cycle

(b)
(i) Progesterone uses negative feedback to inhibit the production of FSH
FSH stimulates the growth of follicles which produce eggs. If the follicles do not grow then eggs are not produced and released. Eggs are never produced as progesterone is continually released. If there is no egg it cannot be fertilised.
(ii) Progesterone is released automatically.

Question 4:
(a) Increased intensity of exercise leads to increased respiration which results in an increase in the concentration of carbon dioxide in the blood. This is detected by chemoreceptors in the aortic arch and carotid bodies. These send nervous impulses to the cardioregulatory accelerator centre in the medulla oblongata. This sends impulses to the SAN centre via the sympathetic nervous system. The SAN stimulates and increase in heart rate.

(b) (i) To act as a control, to allow comparison
(ii) Error bars don't overlap so the results are not due to change (less than 0.05)
All the results of the change in mean heart rate are negative numbers.
Positive Correlation
Quantitative analysis (numbers mentioned?)

Question 5:
(a) Restriction endonuclease
(b) (i) (ii)
(c) (i) Immune system detects it being foreign and attacks it?
(ii) So the process is adjusted accordingly and mistakes are not repeated again/same mistake avoided occurring twice.

Question 6:
(a)
(b)
(i)
(ii)
(iii) Artificial Gene only needs to be inserted once/no other __necessary
Artificial Gene work for a long time
Only tried on rats, may pose dangers in Humans
Long term side-affects of Artificial Gene not known

Question 7:
(a)
(b)
(c) (i) (ii)

Question 8:
(a) (i) (ii)
(b) (i) (ii) (iii)

Question 9:
(a) ((22.9-18)/22.9)*100 = 21.4%
(b)
(i) To allow for perspiration/panting. Water evapourating from skin/mouth allows heat to leave the blood by convection and the core body temperature to fall.
(ii) Food intake increases because metabolic rate increases. Increased respiration produces more heat to increase body temperature, and this requires increased amounts of food/glucose/substrate.

(c) Milk production decreases because metabolic rate/respiration decreases so less ATP is available for secreting milk or synthesising milk proteins.

(d) Skin is exposed to environmental conditions, heat will be lost by conduction/convection/radiation. Rectal temperature more accurate because more insulated.

(e) A Bull is chosen with a relatively low core body temperature/ that doesn't suffer from Heat Stress

(f) Countries have different numbers of people so using percentages allows for comparison between countries

(g) Sorry to any lactose intolerant people :P In past dairy was very small part of diet so not producing much lactase wasn't an issue. Today due to transportation and refridgeration lactase makes up a much larger proportion of our diet. Therefore people who are lactose intolerant are at an evolutionary disadvantage because if they eat dairy products they become ill. Perhaps they do not have as many children or may be more likely to die as a child, so over time a larger proportion of genes passed on will be from lactose tolerant people and more of the population will become so. This is directional selection. This will happen faster in a country that eats more dairy products because lactose intolerant people will be at more of a disadvantage.

Question 10:
Essay question

Some of these answers are wrong. Calculation one was 30455x and 2)a)i is unchanged and 2)a)ii is shortened because it was I band. remember A band stays the same!

[alan-93]

(Original post by holahola)
1c maybe change in amino aicd sequence therefore different tertiary structure

safe....lol that's what i wrote, well it can't be anything else!

[Slavivlad]

(Original post by Picture~Perfect)
I'm going to attempt an unofficial mark scheme, but I'll need your help

Thanks to JimmyK, ChocolatePearl and sydney07 for your help

Question 1:
(a) (i) TGCTAC (ii) UGC
(b) DNA has both introns and exons, whereas mRNA only has exons as introns are removed due to splicing.
(c) Could lead to a different amino acid being inserted into the polypeptide and so different primary structure thus different tertiary structure
(d) Since acetylcholinesterase is inhibited; the acetylcholine diffuses across synaptic cleft, and binds to receptors, triggering an action potential, since no acetylcholinesterase is released the acetylcholine is not broken down; action potentials are continually given off; muscles controlling breathing continually contract; hence can't breath

Question 2:
(a) (i) Shortens (ii) Stays the same
(b) 3046
(c) Myosin head are bound to a molecule of ATP, during contraction this is hydrolysed releasing a large amount of energy. Myosin bind to actin forming cross-bridges and uses the energy to move, pulling along the actin. When the myosin heads detach form the actin another molecule of ATP binds to them. For a strong contraction this action is repeated. If insufficient ATP is provided, this process can not continue, resulting in weaker contractions. Not quite sure that this answer relates to the question. I put something like this: Myosin head contains ATPase which breaks down ATP to ADP and Pi. The energy from this is used for the power stroke and the return of the myosin head to its starting position. People with McArdle's produce less ATP, therefore there's less energy from the breakdown of ATP to be used for muscle contraction and so they have troubles with exercise

Question 3:
(a)
(i) A short time after the concentration of oestrogen begins to rise, the contraction of LH rises
(ii) There is a fall in the concentrate of progesterone at the end of her cycle

(b)
(i) Progesterone uses negative feedback to inhibit the production of FSH
FSH stimulates the growth of follicles which produce eggs. If the follicles do not grow then eggs are not produced and released. Eggs are never produced as progesterone is continually released. If there is no egg it cannot be fertilised. Good, but I mentioned LH too as LH stimulates ovulation and since LH is inhibited by Progesterone, ovulation never occurs so the ovum is never released.
(ii) Progesterone is released automatically.

Question 4:
(a) Increased intensity of exercise leads to increased respiration which results in an increase in the concentration of carbon dioxide in the blood. This is detected by chemoreceptors in the aortic arch and carotid bodies. These send nervous impulses to the cardioregulatory accelerator centre in the medulla oblongata. This sends impulses to the SAN centre via the sympathetic nervous system. The SAN stimulates and increase in heart rate.

(b) (i) To act as a control, to allow comparison
(ii) Error bars don't overlap so the results are not due to change (less than 0.05)
All the results of the change in mean heart rate are negative numbers.
Positive Correlation
Quantitative analysis (numbers mentioned?)
Also mentioned that for all intensities the heart rate of people in Group A is lower than for those in Group B

Question 5:
(a) Restriction endonuclease
(b) (i) This allows the scientists to distinguish between the cells that have taken up the hybrid DNA and those that haven't so that the ones that have can be implanted.
(ii) I put something about the fact that this will allow the Factor IX to be present in the sheep's milk which then can be consumed by hemophiliacs.
(c) (i) Immune system detects it being foreign and attacks it? I put this.
(ii) So the process is adjusted accordingly and mistakes are not repeated again/same mistake avoided occurring twice.

Question 6:
(a) Adrenaline binds to receptors which activates an enzyme within the cells which then produces a chain reaction of enzymes being stimulated which in turn stimulates the breakdown of glycogen into glucose and its absorption into the blood stream.
(b)
(i) Eating carbohydrates will increase glucose concentration as it's being absorbed in the small intestine plus that will lead to a secretion of insulin which will affect the results.
(ii) Type I - there's a lack or no insulin produced, so insulin injections help. Type II - the insulin receptors on the cells lose sensitivity, so increasing insulin should have no effect.
(iii) Artificial Gene only needs to be inserted once/no other __necessary
Artificial Gene work for a long time
Only tried on rats, may pose dangers in Humans
Long term side-affects of Artificial Gene not known

Question 7:

(a) Effects of gravity were measured, but light has an affect on roots too so keeping in the dark prevents this.
(b) That the tip must be important in producing a response, whether or not the root will grow downwards.
(c) (i) IAA is produced which is distributed unevenly. IAA diffuses to the lower side of the root which inhibits cell elongation and growth and so the cells on the upper side of the leaf grow quicker which causes the downward bending.
(ii) IAA is on the lower side of the root again and so it bends downwards as above, but only to 30 degrees rather than 60 as half of the root was removed and so half the IAA was produced which causes this reduction in curvature.

Question 8:
(a) (i) Points overlap and some people with fewer CAG repeats develop the disease later than those with more repeats.
But - negative correlation is present.
(ii) People have kids before any symptoms are displayed, ie some people only develop symptoms in their 60s.
(b) (i) K because most CAG repeats as it's the largest fragment and we know from previous page, the more the CAG repeats - the greater the risk of Huntington's.
(ii) Compare to DNA fragments of known sizes that underwent electrophoresis too.
(iii) DNA was cut in half so both fragments are the same size and so are represented by one band.

Question 9:
(a) ((22.9-18)/22.9)*100 = 21.4%
(b) Cold water cools you from inside, just like hot food/drink warms you up. Replacing water lost through sweating. Do cows sweat ?
(i) To allow for perspiration/panting. Water evapourating from skin/mouth allows heat to leave the blood by convection and the core body temperature to fall.
(ii) Food intake increases because metabolic rate increases. Increased respiration produces more heat to increase body temperature, and this requires increased amounts of food/glucose/substrate.

(c) Milk production decreases because metabolic rate/respiration decreases so less ATP is available for secreting milk or synthesising milk proteins.

(d) Skin is exposed to environmental conditions, heat will be lost by conduction/convection/radiation. Rectal temperature more accurate because more insulated.

(e) A Bull is chosen with a relatively low core body temperature/ that doesn't suffer from Heat Stress

(f) Countries have different numbers of people so using percentages allows for comparison between countries

(g) Sorry to any lactose intolerant people :P In past dairy was very small part of diet so not producing much lactase wasn't an issue. Today due to transportation and refridgeration lactase makes up a much larger proportion of our diet. Therefore people who are lactose intolerant are at an evolutionary disadvantage because if they eat dairy products they become ill. Perhaps they do not have as many children or may be more likely to die as a child, so over time a larger proportion of genes passed on will be from lactose tolerant people and more of the population will become so. This is directional selection. This will happen faster in a country that eats more dairy products because lactose intolerant people will be at more of a disadvantage.

Question 10:
Essay question

Things in red are what I put, hope this helps.

[sydney07]

7 a) Avoid their negative phototropism
7 b) The tip is the part of the plant that grows, the cells are totipotent
7 ci) IAA travels on upper side of the the root; upper side of root grows; this creates a natural lean down into the soil following gravity tropism
7 cii) IAA travels on the upper side; with the upper half of the root tip removed, less IAA travels in the roots; therefore less growth on upper half, so less of a lean, hence curvature is only 30 not 60

[freddy]

(Original post by Picture~Perfect)

(f) Countries have different numbers of people so using percentages allows for comparison between countries

is it ok to say different populations in different countries hence allows comparison???

[freddy]

i though the iaa queston was about gravity causing iaa to redistribute to the bottom half??? is that right?:/