ChrisC177
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1: DNA

a) Why is DNA described as the universal code? (or something along those lines) (1)
I put DNA nucleotides same for all life on Earth
RNA nucleotides

b) Number of possible triplet codes (1)
64

c) What is the process of removing introns called (1)
Splicing

di) Mutation questions: delete based changes it (3)
Causes a shift so all following triplets code for different amino acids

ii) Substitution (2)
Was in the introns, so would be spliced out and would therefore have no effect


2: Maggots!

a) The maggots were said to exhibit a taxis, why is this? (2)
The maggots showed a directional response in response to a stimuli, moving towards a specific temperature

b) Why would the maggots being grown in that culture cause them to react in that way when without food? (3)
They were grown at a certain temperature and given a constant food supply, meaning they would associate abundance of food with that temperature; this would mean they would exhibit a taxis in response, by moving to the temperature had previously given them this abundant food supply. (I'm sure there's more to that)

c) Why kept dim and dark (2)
So they don't exhibit kinesis in response to light
No directional response to light
Someone suggested temperature, as well


3: DNA

a) What is used to form cDNA from mRNA? (1)
Reverse transcriptase

b) Why would the DNA probe bind only to allele A? (2)
DNA probes complementary to only one specific base sequence, which would be found on allele A and not a

c) Explain the curve of H (3)
Increased cycles of PCR leads to many more copies of the allele that the gene probe binds to, equation 2^x, x being the number of cycles, giving an exponential increase. This means a lot more allele for probe to bind to, meaning more intense colour

d) Which was heterozygous? (2)
The lower one, G, as less copies of the allele, meaning half as much for gene probe to bind to, so less colour given


4: Cancer and infertility


a) Follicle destroyed by Chemo, why does this lead to high FSH levels? (2)
Oestrogen produced in follicles inhibits FSH production in low concentrations, without follicles no oestrogen, meaning FSH levels will be uninhibited and uncontrolled.

b) Why would keeping FSH low increase later fertility? (3)
By reducing FSH, you are preventing growth of follicles. Since chemotherapy affects growing follicles, less will be harmed when FSH levels are reduced, since FSH is stimulates follicle growth. If less follicles are destroyed, then the patient will have more ova surviving after treatment, which can be fertilised by sperm for childbirth.

c) Similar molecule shape to FSH producing hormone, why does this reduce FSH production? (2)
The drug has a similar shape to the normal hormone, meaning competitive inhibition. It is complementary to the receptor for the normal hormone, so it will bind to it, inhibiting the normal hormone from doing so. There it inhibits FSH production.


5: Nerves


a) Why do myelinated nuerons conduct faster than unmyelinated ones? (3)
Myelin sheathes acts as an insulator and causes saltatory conduction, meaning action potentials only generated at the nodes of ranvier, so nerve impulses are conducted between them. Without myelination, action potentials must be propagated throughout the whole axon relying on diffusion of ions, which is slower

b) Scientist performed statistical test, got a value of p = 0.047, evaluate (2)
P-value below 0.05, meaning there is a less than 5% probability results are due to chance rather than a real biological factor

c) A scientist evaluated the graph and said that myelinated brain sheath is linked to chance of getting dementia (3)
Significant difference between control group and dementia groups. Groups showed large amount of variation between different types of dementia, maybe casting doubt on conclusion. Other factors could be having an affect, not established that one causes the other. Small sample sizes of the groups means they may not be representative of their respective groups


6: Uhh, more DNA? Not even sure how to summarise this question!

a) What is a transcriptional factor? (2)
A protein that allows the binding of mRNA to DNA, therefore controlling the formation of proteins from amino acids

b) Why would a neurone die when NADH proton dissociation causing proteins are inhibited, or something (3)
I put about how this would prevent the electron transport chain occurring, which would lead to a large reduction in production of ATP, meaning the neuron would not have a supply of energy and would therefore die (not sure if you needed to say about action potentials, some people did, some didn't?) Energy needed to repair damage to the neurone?

c) Why are two protein channels required? (2)
Fact that mitochondria have an inner and outer membrane, both of which the protein would need to diffuse through.


7: Control of blood sugar levels


a) Explain how increasing levels of glycogen formation in the liver lowers blood sugar levels (2)
Increase in formation of glycogen from glucose means decreased glucose concentration in the liver. This means glucose will diffuse down a concentration gradient into the cells of the liver; as it is being continually converted into glycogen, this concentration gradient is maintained until blood sugar levels normalise.

b) Why they were classed as high risk patients (2)
They had a low sensitivity to insulin already; I put about it being so low the standard error overlapped with those people who did actually have diabetes

c) Scientist said some who had GB were 'cured' of diabetes, while some patients did not show much improvement (4)
Showed a large increase in the mean, but with a very wide standard deviation, which shows large spread of data around the mean. This means some showed a large improvement, while others would have shown very little; the standard deviation overlaps with the original before GB.


8: Muscles / phosphocreatine


a) Describe the role of phosphocreatine (or words to that effect) (2)
Used to convert ADP into ATP in a condensation reaction. Acts as a store of inorganic phosphate, which can be combined with ADP when large amounts of ATP are required for muscle contraction. Something about ATP being rapidly broken down in cells, making phosphocreatine a more viable longer term storage of it.

b) Suggest why there is variation in time taken for PC to reform between people of the same age (1)
Personally I went with genetic variation
Probably something about different people needing different amounts of ATP for crossbridge cycle

c) Question about fast twitch muscles and how this fits with the results (4)
This question was a bit horrible. Fast twitch muscles have a larger supply of phosphocreatine, which is used to provide a source of inorganic phosphate to form ATP from ADP. This fits results because as people get older, myosin / actin weakens, meaning more ATP is required to fully go through the crossbridge cycle, meaning less ATP is available for reforming phosphocreatine.


9: Respiration / photosynthesis

a) Percentages I got were around 39.8 and 35.2 (not 100% sure on that) (2)

b) The student said that these results showed plants respire more than organisms in the environment, why is this incorrect (2)
Wasn't sure about this, someone suggested that not all organisms were included, so their CO2 production would actually be higher. I put that leaves showed a much smaller amount of CO2 production, so would be lower in total when combined with the stem / roots

c) Describe the differences between the two lines on the graph (under trees and not under trees) (2)
Under trees was higher
Showed a small, temporary increase at different times of day
Not really sure

d) Why would there be a higher rate of soil respiration under trees than when not under trees? (2)
Under trees more detritus (leaves, etc.) meaning more saprobiotic microorganisms breaking it down and respiring, producing CO2
Or more roots under trees, which would respire and produce CO2

e) Measurements needed to calculate CO2 given off [2]
This definitely seemed like another of the unit 4 style questions; I went with mass of the organism, volume of CO2 given off, and time

f) Why was an increase in the rate of photosynthesis followed by an increase in the rate of respiration (2)
Increased photosynthesis means more glucose produced, which would be the limiting factor in rate of respiration, therefore respiration rate also increases.
Or increased photosynthesis means increased O2 production, which diffuses into soil, meaning microorganisms can undergo more respiration

f) Why delay between increased photosynthesis and increased respiration? (1)
Glucose takes time to be transported through the plant from leaves to provide more glucose for respiration in roots, stem, etc.
Possibly time required for oxygen produced by the tree to diffuse into the soil containing microorganisms

g) Why were these measurements taken in the dark? (2)
During the day, plants would undergo photosynthesise, a process which uses CO2, affecting the results for CO2 given off by respiration

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absta101
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For question 5 c) The sample size of all the groups were very low and so they might not be representative of their respective groups. (the control group only had 12 people!)
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ChrisC177
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(Original post by absta101)
For question 5 c) The sample size of all the groups were very low and so they might not be representative of their respective groups. (the control group only had 12 people!)
Ah, darn, didn't even notice that! Thanks, added that in
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absta101
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3 c) G was heterozygous (lower curve)

5 b) Maybe say that energy is needed to repair the cell from damage? (Not sure why the neurone needs energy to survive. I do know that they get repaired though.)

8 f) I thought you had to say that it takes time for the oxygen produced by the tree to diffuse down into the soil containing the respiring microorganisms. Not sure on that one though.
---

Also, the sensitivity to diabetes after GBS was 1.3 (+-0.80) for non-diabetics and 1.1 (+-0.87) for type 2 patients. I think before the GBS it was like 0.5 and 0.4 on both of them. I don't remember the deviation though.
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jennybooth95
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You missed out the first part of the question on phosphocreatine. I can't fully remember the question, something about its role? That was 2/3 marks. Then there was a 1 marker on why there was variation for people of the same ages in how long PC took to be restored.
Also, in the diabetes it asks how increasing levels of glycogen in the liver cells lowers blood glucose concentration. 2/3 marks. And the very last question of 9 was why were the measurements taken in the dark not in the light.
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ChrisC177
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(Original post by jennybooth95)
You missed out the first part of the question on phosphocreatine. I can't fully remember the question, something about its role? That was 2/3 marks. Then there was a 1 marker on why there was variation for people of the same ages in how long PC took to be restored.
Also, in the diabetes it asks how increasing levels of glycogen in the liver cells lowers blood glucose concentration. 2/3 marks. And the very last question of 9 was why were the measurements taken in the dark not in the light.
Thanks, added those in now; not entirely sure of my answers for all of them, though
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The Lawful T.J
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Question 4 involves the Probability & Chance question. As well as having that evaluation question (which was 3 marks, btw).
Another question started off with "What is a transcriptional factor?", which also included the question about the protein which causes the release of protons and electrons from the reduced NAD on the cristae (something regarding the death of a neurone) as well as the whole "two carrier proteins" question. (Out of 7, that question).
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The Lawful T.J
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I don't know what order the questions go in, but here goes:
Question 1:
1 - Universal [1]
2 - 64 [1]
3 - Splicing [1]
4 - Deletion mutation [3]
5 - Substitution mutation [2]
Question 2:
1 - How worms showed taxis [2]
2 - Explanation of movement [3]
3 - Why dim, even light used [2]
Question 3:
1 - Why destruction ↑ FSH [2]
2 - How the AF would help reduce the risk of being unable to have a child [3]
3 - How the AF reduced FSH [2]
Question 4:
1 - Why a myelinated axon is faster [3]
2 - Probability & Chance [2]
3 - Evaluation of dementia study [3]
Question 5:
1 - What is a transcriptional factor? [2]
2 - Death of a neurone [3]
3 - Why two carrier proteins needed [2]
Question 6:
1 - What does PC do? [2]
2 - Variation [1]
3 - Fast muscle fibres [4]
Question 7:
1 -How does insulin binding to the liver(?) decrease glucose levels etc [2]
2 - Why were people w/o T2 diabetes at risk? [2]
3 - Curing diabetes (T2) evaluation [4]
Question 8:
1 - mRNA → cDNA [1]
2 - Why the DNA probe only binds to allele 'A' [2]
3 - Describe/Explain the curve for H [3]
4 - Which was heterozygous and how can you tell? [2]
Question 9:
1 - % Calculation [2]
2 - Student's conclusion (invalid) [2]
3 - What measurements needed [2]
4 - Why measurements taken in the dark [2]
5 - Why respiration levels in soil under the tree was higher than not under the tree [2]
6 - Describe the differences between the (mean) respiration rates of soil under tree/not under [2]
7 - Why a decrease in photosynthesis increased (caused a peak) in the rate of respiration or words to that extent [2]
8 - Why is there a delay [1]
Question 10:
a - exchange in external environment to maintain internal environment [25]; or
b - tranfer of energy between organisms(?) [25].
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The_Blade
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(Original post by The Lawful T.J)
I don't know what order the questions go in, but here goes:
Question 1:
1 - Universal [1]
2 - 64 [1]
3 - Splicing [1]
4 - Deletion mutation [3]
5 - Substitution mutation [2]
Question 2:
1 - How worms showed taxis [2]
2 - Explanation of movement [3]
3 - Why dim, even light used [2]
Question 3:
1 - Why destruction ↑ FSH [2]
2 - How the AF would help reduce the risk of being unable to have a child [3]
3 - How the AF reduced FSH [2]
Question 4:
1 - Why a myelinated axon is faster [3]
2 - Probability & Chance [2]
3 - Evaluation of dementia study [3]
Question 5:
1 - What is a transcriptional factor? [2]
2 - Death of a neurone [3]
3 - Why two carrier proteins needed [2]
Question 6:
1 - What does PC do? [2]
2 - Variation [1]
3 - Fast muscle fibres [4]
Question 7:
1 -How does insulin binding to the liver(?) decrease glucose levels etc [2]
2 - Why were people w/o T2 diabetes at risk? [2]
3 - Curing diabetes (T2) evaluation [4]
Question 8:
1 - mRNA → cDNA [1]
2 - Why the DNA probe only binds to allele 'A' [2]
3 - Describe/Explain the curve for H [3]
4 - Which was heterozygous and how can you tell? [2]
Question 9:
1 - % Calculation [2]
2 - Student's conclusion (invalid) [2]
3 - What measurements needed [2]
4 - Why measurements taken in the dark [2]
5 - Why respiration levels in soil under the tree was higher than not under the tree [2]
6 - Describe the differences between the (mean) respiration rates of soil under tree/not under [2]
7 - Why a decrease in photosynthesis increased (caused a peak) in the rate of respiration or words to that extent [2]
8 - Why is there a delay [1]
Question 10:
a - exchange in external environment to maintain internal environment [25]; or
b - tranfer of energy between organisms(?) [25].
Is this everything and all marks are correct?

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KelseyL
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For question 3a it said "use your knowledge of hormonal interactions" so I'm 99.9% sure that "hormone-receptor complex forms" should have been mentioned!!!
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ChrisC177
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Wow, I clearly should have left it to you

The only one I slightly disagree with, was this one "7 - Why a decrease in photosynthesis increased (caused a peak) in the rate of respiration or words to that extent [2]", which I thought was in an increase in the rate of photosynthesis? Could be I just completely read it wrong in the exam, though
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The Lawful T.J
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(Original post by ChrisC177)
Wow, I clearly should have left it to you

The only one I slightly disagree with, was this one "7 - Why a decrease in photosynthesis increased (caused a peak) in the rate of respiration or words to that extent [2]", which I thought was in an increase in the rate of photosynthesis? Could be I just completely read it wrong in the exam, though
No, no you shouldn't have! Aha
I needed to know the questions so I could estimate my possible grade.
I didn't know what that question was! You're probably correct

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Totally Fressh
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(Original post by ChrisC177)
1: DNA

a) Why is DNA described as the universal code? (or something along those lines) (1)
I put DNA nucleotides same for all life on Earth

b) Number of possible triplet codes (1)
64

c) What is the process of removing introns called (1)
Splicing

di) Mutation questions: delete based changes it (3)
Causes a shift so all following triplets code for different amino acids

ii) Substitution (2)
Was in the introns, so would be spliced out and would therefore have no effect


2: Maggots!

a) The maggots were said to exhibit a taxis, why is this? (2)
The maggots showed a directional response in response to a stimuli, moving towards a specific temperature

b) Why would the maggots being grown in that culture cause them to react in that way when without food? (3)
They were grown at a certain temperature and given a constant food supply, meaning they would associate abundance of food with that temperature; this would mean they would exhibit a taxis in response, by moving to the temperature had previously given them this abundant food supply. (I'm sure there's more to that)

c) Why kept dim and dark (2)
So they don't exhibit kinesis in response to light
No directional response to light
Someone suggested temperature, as well


3: DNA

a) What is used to form cDNA from mRNA? (1)
Reverse transcriptase

b) Why would the DNA probe bind only to allele A? (2)
DNA probes complementary to only one specific base sequence, which would be found on allele A and not a

c) Explain the curve of H (3)
Increased cycles of PCR leads to many more copies of the allele that the gene probe binds to, equation 2^x, x being the number of cycles, giving an exponential increase. This means a lot more allele for probe to bind to, meaning more intense colour

d) Which was heterozygous? (2)
The lower one, G, as less copies of the allele, meaning half as much for gene probe to bind to, so less colour given


4: Cancer and infertility


a) Follicle destroyed by Chemo, why does this lead to high FSH levels? (2)
Oestrogen produced in follicles inhibits FSH production in low concentrations, without follicles no oestrogen, meaning FSH levels will be uninhibited and uncontrolled.

b) Why would keeping FSH low increase later fertility? (3)
By reducing FSH, you are preventing growth of follicles. Since chemotherapy affects growing follicles, less will be harmed when FSH levels are reduced, since FSH is stimulates follicle growth. If less follicles are destroyed, then the patient will have more ova surviving after treatment, which can be fertilised by sperm for childbirth.

c) Similar molecule shape to FSH producing hormone, why does this reduce FSH production? (2)
The drug has a similar shape to the normal hormone, meaning competitive inhibition. It is complementary to the receptor for the normal hormone, so it will bind to it, inhibiting the normal hormone from doing so. There it inhibits FSH production.


5: Nerves


a) Why do myelinated nuerons conduct faster than unmyelinated ones? (3)
Myelin sheathes acts as an insulator and causes saltatory conduction, meaning action potentials only generated at the nodes of ranvier, so nerve impulses are conducted between them. Without myelination, action potentials must be propagated throughout the whole axon relying on diffusion of ions, which is slower

b) Scientist performed statistical test, got a value of p = 0.047, evaluate (2)
P-value below 0.05, meaning there is a less than 5% probability results are due to chance rather than a real biological factor

c) A scientist evaluated the graph and said that myelinated brain sheath is linked to chance of getting dementia (3)
Significant difference between control group and dementia groups. Groups showed large amount of variation between different types of dementia, maybe casting doubt on conclusion. Other factors could be having an affect, not established that one causes the other. Small sample sizes of the groups means they may not be representative of their respective groups


6: Uhh, more DNA? Not even sure how to summarise this question!

a) What is a transcriptional factor? (2)
A protein that allows the binding of mRNA to DNA, therefore controlling the formation of proteins from amino acids

b) Why would a neurone die when NADH proton dissociation causing proteins are inhibited, or something (3)
I put about how this would prevent the electron transport chain occurring, which would lead to a large reduction in production of ATP, meaning the neuron would not have a supply of energy and would therefore die (not sure if you needed to say about action potentials, some people did, some didn't?) Energy needed to repair damage to the neurone?

c) Why are two protein channels required? (2)
Fact that mitochondria have an inner and outer membrane, both of which the protein would need to diffuse through.


7: Control of blood sugar levels


a) Explain how increasing levels of glycogen formation in the liver lowers blood sugar levels (2)
Increase in formation of glycogen from glucose means decreased glucose concentration in the liver. This means glucose will diffuse down a concentration gradient into the cells of the liver; as it is being continually converted into glycogen, this concentration gradient is maintained until blood sugar levels normalise.

b) Why they were classed as high risk patients (2)
They had a low sensitivity to insulin already; I put about it being so low the standard error overlapped with those people who did actually have diabetes

c) Scientist said some who had GB were 'cured' of diabetes, while some patients did not show much improvement (4)
Showed a large increase in the mean, but with a very wide standard deviation, which shows large spread of data around the mean. This means some showed a large improvement, while others would have shown very little; the standard deviation overlaps with the original before GB.


8: Muscles / phosphocreatine


a) Describe the role of phosphocreatine (or words to that effect) (2)
Used to convert ADP into ATP in a condensation reaction. Acts as a store of inorganic phosphate, which can be combined with ADP when large amounts of ATP are required for muscle contraction. Something about ATP being rapidly broken down in cells, making phosphocreatine a more viable longer term storage of it.

b) Suggest why there is variation in time taken for PC to reform between people of the same age (1)
Personally I went with genetic variation
Probably something about different people needing different amounts of ATP for crossbridge cycle

c) Question about fast twitch muscles and how this fits with the results (4)
This question was a bit horrible. Fast twitch muscles have a larger supply of phosphocreatine, which is used to provide a source of inorganic phosphate to form ATP from ADP. This fits results because as people get older, myosin / actin weakens, meaning more ATP is required to fully go through the crossbridge cycle, meaning less ATP is available for reforming phosphocreatine.


9: Respiration / photosynthesis

a) Percentages I got were around 39.8 and 35.2 (not 100% sure on that) (2)

b) The student said that these results showed plants respire more than organisms in the environment, why is this incorrect (2)
Wasn't sure about this, someone suggested that not all organisms were included, so their CO2 production would actually be higher. I put that leaves showed a much smaller amount of CO2 production, so would be lower in total when combined with the stem / roots

c) Describe the differences between the two lines on the graph (under trees and not under trees) (2)
Under trees was higher
Showed a small, temporary increase at different times of day
Not really sure

d) Why would there be a higher rate of soil respiration under trees than when not under trees? (2)
Under trees more detritus (leaves, etc.) meaning more saprobiotic microorganisms breaking it down and respiring, producing CO2
Or more roots under trees, which would respire and produce CO2

e) Measurements needed to calculate CO2 given off [2]
This definitely seemed like another of the unit 4 style questions; I went with mass of the organism, volume of CO2 given off, and time

f) Why was an increase in the rate of photosynthesis followed by an increase in the rate of respiration (2)
Increased photosynthesis means more glucose produced, which would be the limiting factor in rate of respiration, therefore respiration rate also increases.
Or increased photosynthesis means increased O2 production, which diffuses into soil, meaning microorganisms can undergo more respiration

f) Why delay between increased photosynthesis and increased respiration? (1)
Glucose takes time to be transported through the plant from leaves to provide more glucose for respiration in roots, stem, etc.
Possibly time required for oxygen produced by the tree to diffuse into the soil containing microorganisms

g) Why were these measurements taken in the dark? (2)
During the day, plants would undergo photosynthesise, a process which uses CO2, affecting the results for CO2 given off by respiration

Question 1 - the universal code question was something about how the genetic code was described as being universal. for thisyou cant say DNA it has to be RNA cause in A2 we learnt that RNA is the genetic code
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Major-MM
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(Original post by ChrisC177)
1: DNA

a) Why is DNA described as the universal code? (or something along those lines) (1)
I put DNA nucleotides same for all life on Earth
RNA nucleotides

b) Number of possible triplet codes (1)
64

c) What is the process of removing introns called (1)
Splicing

di) Mutation questions: delete based changes it (3)
Causes a shift so all following triplets code for different amino acids

ii) Substitution (2)
Was in the introns, so would be spliced out and would therefore have no effect


2: Maggots!

a) The maggots were said to exhibit a taxis, why is this? (2)
The maggots showed a directional response in response to a stimuli, moving towards a specific temperature

b) Why would the maggots being grown in that culture cause them to react in that way when without food? (3)
They were grown at a certain temperature and given a constant food supply, meaning they would associate abundance of food with that temperature; this would mean they would exhibit a taxis in response, by moving to the temperature had previously given them this abundant food supply. (I'm sure there's more to that)

c) Why kept dim and dark (2)
So they don't exhibit kinesis in response to light
No directional response to light
Someone suggested temperature, as well


3: DNA

a) What is used to form cDNA from mRNA? (1)
Reverse transcriptase

b) Why would the DNA probe bind only to allele A? (2)
DNA probes complementary to only one specific base sequence, which would be found on allele A and not a

c) Explain the curve of H (3)
Increased cycles of PCR leads to many more copies of the allele that the gene probe binds to, equation 2^x, x being the number of cycles, giving an exponential increase. This means a lot more allele for probe to bind to, meaning more intense colour

d) Which was heterozygous? (2)
The lower one, G, as less copies of the allele, meaning half as much for gene probe to bind to, so less colour given


4: Cancer and infertility


a) Follicle destroyed by Chemo, why does this lead to high FSH levels? (2)
Oestrogen produced in follicles inhibits FSH production in low concentrations, without follicles no oestrogen, meaning FSH levels will be uninhibited and uncontrolled.

b) Why would keeping FSH low increase later fertility? (3)
By reducing FSH, you are preventing growth of follicles. Since chemotherapy affects growing follicles, less will be harmed when FSH levels are reduced, since FSH is stimulates follicle growth. If less follicles are destroyed, then the patient will have more ova surviving after treatment, which can be fertilised by sperm for childbirth.

c) Similar molecule shape to FSH producing hormone, why does this reduce FSH production? (2)
The drug has a similar shape to the normal hormone, meaning competitive inhibition. It is complementary to the receptor for the normal hormone, so it will bind to it, inhibiting the normal hormone from doing so. There it inhibits FSH production.


5: Nerves


a) Why do myelinated nuerons conduct faster than unmyelinated ones? (3)
Myelin sheathes acts as an insulator and causes saltatory conduction, meaning action potentials only generated at the nodes of ranvier, so nerve impulses are conducted between them. Without myelination, action potentials must be propagated throughout the whole axon relying on diffusion of ions, which is slower

b) Scientist performed statistical test, got a value of p = 0.047, evaluate (2)
P-value below 0.05, meaning there is a less than 5% probability results are due to chance rather than a real biological factor

c) A scientist evaluated the graph and said that myelinated brain sheath is linked to chance of getting dementia (3)
Significant difference between control group and dementia groups. Groups showed large amount of variation between different types of dementia, maybe casting doubt on conclusion. Other factors could be having an affect, not established that one causes the other. Small sample sizes of the groups means they may not be representative of their respective groups


6: Uhh, more DNA? Not even sure how to summarise this question!

a) What is a transcriptional factor? (2)
A protein that allows the binding of mRNA to DNA, therefore controlling the formation of proteins from amino acids

b) Why would a neurone die when NADH proton dissociation causing proteins are inhibited, or something (3)
I put about how this would prevent the electron transport chain occurring, which would lead to a large reduction in production of ATP, meaning the neuron would not have a supply of energy and would therefore die (not sure if you needed to say about action potentials, some people did, some didn't?) Energy needed to repair damage to the neurone?

c) Why are two protein channels required? (2)
Fact that mitochondria have an inner and outer membrane, both of which the protein would need to diffuse through.


7: Control of blood sugar levels


a) Explain how increasing levels of glycogen formation in the liver lowers blood sugar levels (2)
Increase in formation of glycogen from glucose means decreased glucose concentration in the liver. This means glucose will diffuse down a concentration gradient into the cells of the liver; as it is being continually converted into glycogen, this concentration gradient is maintained until blood sugar levels normalise.

b) Why they were classed as high risk patients (2)
They had a low sensitivity to insulin already; I put about it being so low the standard error overlapped with those people who did actually have diabetes

c) Scientist said some who had GB were 'cured' of diabetes, while some patients did not show much improvement (4)
Showed a large increase in the mean, but with a very wide standard deviation, which shows large spread of data around the mean. This means some showed a large improvement, while others would have shown very little; the standard deviation overlaps with the original before GB.


8: Muscles / phosphocreatine


a) Describe the role of phosphocreatine (or words to that effect) (2)
Used to convert ADP into ATP in a condensation reaction. Acts as a store of inorganic phosphate, which can be combined with ADP when large amounts of ATP are required for muscle contraction. Something about ATP being rapidly broken down in cells, making phosphocreatine a more viable longer term storage of it.

b) Suggest why there is variation in time taken for PC to reform between people of the same age (1)
Personally I went with genetic variation
Probably something about different people needing different amounts of ATP for crossbridge cycle

c) Question about fast twitch muscles and how this fits with the results (4)
This question was a bit horrible. Fast twitch muscles have a larger supply of phosphocreatine, which is used to provide a source of inorganic phosphate to form ATP from ADP. This fits results because as people get older, myosin / actin weakens, meaning more ATP is required to fully go through the crossbridge cycle, meaning less ATP is available for reforming phosphocreatine.


9: Respiration / photosynthesis

a) Percentages I got were around 39.8 and 35.2 (not 100% sure on that) (2)

b) The student said that these results showed plants respire more than organisms in the environment, why is this incorrect (2)
Wasn't sure about this, someone suggested that not all organisms were included, so their CO2 production would actually be higher. I put that leaves showed a much smaller amount of CO2 production, so would be lower in total when combined with the stem / roots

c) Describe the differences between the two lines on the graph (under trees and not under trees) (2)
Under trees was higher
Showed a small, temporary increase at different times of day
Not really sure

d) Why would there be a higher rate of soil respiration under trees than when not under trees? (2)
Under trees more detritus (leaves, etc.) meaning more saprobiotic microorganisms breaking it down and respiring, producing CO2
Or more roots under trees, which would respire and produce CO2

e) Measurements needed to calculate CO2 given off [2]
This definitely seemed like another of the unit 4 style questions; I went with mass of the organism, volume of CO2 given off, and time

f) Why was an increase in the rate of photosynthesis followed by an increase in the rate of respiration (2)
Increased photosynthesis means more glucose produced, which would be the limiting factor in rate of respiration, therefore respiration rate also increases.
Or increased photosynthesis means increased O2 production, which diffuses into soil, meaning microorganisms can undergo more respiration

f) Why delay between increased photosynthesis and increased respiration? (1)
Glucose takes time to be transported through the plant from leaves to provide more glucose for respiration in roots, stem, etc.
Possibly time required for oxygen produced by the tree to diffuse into the soil containing microorganisms

g) Why were these measurements taken in the dark? (2)
During the day, plants would undergo photosynthesise, a process which uses CO2, affecting the results for CO2 given off by respiration

For question 4) a), I wrote:
- The destruction of the follicle by the chemotherapy prevents the formation of the corpus luteum.
- The corpus luteum acts as a temporary endocrine system, secreting progesterone which inhibits the release of FSH by the pituitary.
- Therefore, if the corpus luteum is not formed, due to follicle destruction, then FSH is not inhibited by progesterone. As a result, concentrations of FSH increase

Would that get the marks do you think?
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Lucy_95
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#15
(Original post by absta101)
For question 5 c) The sample size of all the groups were very low and so they might not be representative of their respective groups. (the control group only had 12 people!)
But the standard error bars didn't overlap, and standard error takes into account the numbers of people in each group?

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Sandwho
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What do you think the grade boundaries will be like for this paper?
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Lou1228
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(Original post by Major-MM)
For question 4) a), I wrote:
- The destruction of the follicle by the chemotherapy prevents the formation of the corpus luteum.
- The corpus luteum acts as a temporary endocrine system, secreting progesterone which inhibits the release of FSH by the pituitary.
- Therefore, if the corpus luteum is not formed, due to follicle destruction, then FSH is not inhibited by progesterone. As a result, concentrations of FSH increase

Would that get the marks do you think?
I wrote the same, :/ do you reckon we would get at least one out of the three?
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The Lawful T.J
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(Original post by Lou1228)
I wrote the same, :/ do you reckon we would get at least one out of the three?
It was only 2 marks...
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Lou1228
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(Original post by The Lawful T.J)
It was only 2 marks...
oh right, thanks
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The Lawful T.J
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(Original post by Lou1228)
oh right, thanks
And I'd reckon you'd get one, for saying something about FSH not being inhibited.

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