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OCR A H420/03- Unified Biology 2017 Unofficial Markscheme
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My answers are probably not that great so please contribute 
1 a) circle the R group (1)
![Image]()
The entire top part is the R group
b) What does this conclude about the chemical properties of component X and leu?(1)
ans. leu is more soluble than component X/ leu is more polar than component X
c) 1.5cm away from origin (plotted on diagram) (3)
d) What material is used in the stationary phase (1)
ans. aluminium oxide or silica gel or cellulose
e) Where is the exact location of photosynthetic pigments in the chloroplasts?(2)
ans. It is present in the photosystem of thylakoids
f) Difference between electrophoresis and chromatography (3)
Electrophoresis uses cathode and anode, chromatography doesnt
Electrophoresis uses aragose gel where as chromatography uses silica gel
Electrophoresis takes longer than chromatography
Now i don't know the order of questions so save me
Maths question 1:- 800% increase = 8550 kJ(2)
Maths question 2:- 11% (2)
Maths question 3:- hardy Weinberg 2% (3)
Maths question 4:- serial dilution ( how was that worth only 2 marks)
3750000
Protein structures:- secondary, quaternary, primary, tertiary (2)
What does this suggest about the antibody structure and what does the antibody binds to? (2)
Antibody binds to another molecule other than gliadin and hence the variable region is complimentary to another molecule
6 marker on the student measure heart rate and then calcualting student t test:- (6)
Same Significant figures throughout the table- making the student t test more reliable
Same time of the day, as the day goes by the temperature increases in the afternoon. rate of respiration is affected by temperature and hence affects the heart rate indirectly.
Ask for asthama- could produce anomalous result
Smaller intervals- every 200m making the data more accurate
Do repeats etc
Use suitable units in the table
What type of adaptation were the striped tiger furs? (1)
Structural adaptation/ Anatomical adaptation
6 marker on how striped tigers mutated from non striped:- (6)
Striped tigers were put under selection pressure and this led to a random mutation in the allele which gave the phenotype of striped tigers. As tigers have interspecific and intraspecific competition for food, the striped tigers were able to camouflage with the nature very well and hence had a higher success rate with their prey. This lead to out competing the non striped tigers and the striped tigers were able to survive and reproduce. Over several generations the population of non striped decreased and the allele frequency decrease of non striped decreased in the gene pool. This is also known as natural selection
Student doing experiment on effect of temperature on rate of respiration and evaluating if his experiment gives valid results (3)
He did repeats hence making it valid.
He had suitable interval of 5 degrees and 6 data to be able to compare and see the trend
The ph was the measurement of H+ in oxidative phosphorylation and hence the results should be valid
The critical value was more than the given value ( or vice versa) and hence there was no no significant difference in the mean
Autoimmune disease attacking nervous system (2)
Immune system attacks the cells of the nervous system i,e the neurons and since neurons are already differentiated, they cannot be replicated and hence the damage is permanent. The immune system does this by detecting the antigen of neurons as foreign.
Look at the figure and suggest how the autoimmune disease causes the slow movement of impulse? (2)
Myelin sheath is removed in the affected neuron and hence this stops the saltatory conduction from happening leading to leaks in the flow of action potential.
The symptoms only showed in MC and not the other one?(2)
1. Paralysis??
2. lack of reflex action?
How does the autoimmune disease cause change in neuromuscular junction? (2)
????
Explain and suggest the changes happening due to factors and type of respiration? (3)
The yeast is respiring anaerobically and rate is very fast
This leads to lack of glucose molecule and cumulation of ethanol.
The yeast starts converting ethanol into acetyl coA and at around 8h aerobic respiration starts
The CO2 production hits 0 at around 8h but rises after words due to decarboxylation of carbons in krebs cycle as coA enters Kreb.
The Nitrogen cycle (4)
Plant roots,
NO2- goes to NO3-
NO3- goes to N2 and
the last bacteria was in air
The enzyme diagram (4)
CO was non competitive inhibitor as it binds to alosteric site and this can change the shape of the active site
H was competitive inhibitor with N2 being the actual substrate
Iron and sulfur were prosthetic groups
Leghaemoglobin (2)
Point 1:- Has high affinity of oxygen and hence changes the rate of nitrogenous.
Point 2:- ???
What should you do to make sure that the culture is in best conditions for replication? (2)
Sterilize the area and make sure that the area doesn't contain any other microbes. Heat up the inoculating loop before culturing the bacteria
How are the insect tracheal increase surface area for gas exchange? (1)
They have a lot of spiracles and can removed tracheal fluid to increase the surface area for diffusion
How are fish gills adapted to increase the surface area for gas exchange? (1)
Gills have lamellae which increases surface area
Fill in the blank
Goblet cells, noradrenaline, diaphragm, forced
1 a) circle the R group (1)
The entire top part is the R group
b) What does this conclude about the chemical properties of component X and leu?(1)
ans. leu is more soluble than component X/ leu is more polar than component X
c) 1.5cm away from origin (plotted on diagram) (3)
d) What material is used in the stationary phase (1)
ans. aluminium oxide or silica gel or cellulose
e) Where is the exact location of photosynthetic pigments in the chloroplasts?(2)
ans. It is present in the photosystem of thylakoids
f) Difference between electrophoresis and chromatography (3)
Electrophoresis uses cathode and anode, chromatography doesnt
Electrophoresis uses aragose gel where as chromatography uses silica gel
Electrophoresis takes longer than chromatography
Now i don't know the order of questions so save me
Maths question 1:- 800% increase = 8550 kJ(2)
Maths question 2:- 11% (2)
Maths question 3:- hardy Weinberg 2% (3)
Maths question 4:- serial dilution ( how was that worth only 2 marks)
3750000
Protein structures:- secondary, quaternary, primary, tertiary (2)
What does this suggest about the antibody structure and what does the antibody binds to? (2)
Antibody binds to another molecule other than gliadin and hence the variable region is complimentary to another molecule
6 marker on the student measure heart rate and then calcualting student t test:- (6)
Same Significant figures throughout the table- making the student t test more reliable
Same time of the day, as the day goes by the temperature increases in the afternoon. rate of respiration is affected by temperature and hence affects the heart rate indirectly.
Ask for asthama- could produce anomalous result
Smaller intervals- every 200m making the data more accurate
Do repeats etc
Use suitable units in the table
What type of adaptation were the striped tiger furs? (1)
Structural adaptation/ Anatomical adaptation
6 marker on how striped tigers mutated from non striped:- (6)
Striped tigers were put under selection pressure and this led to a random mutation in the allele which gave the phenotype of striped tigers. As tigers have interspecific and intraspecific competition for food, the striped tigers were able to camouflage with the nature very well and hence had a higher success rate with their prey. This lead to out competing the non striped tigers and the striped tigers were able to survive and reproduce. Over several generations the population of non striped decreased and the allele frequency decrease of non striped decreased in the gene pool. This is also known as natural selection
Student doing experiment on effect of temperature on rate of respiration and evaluating if his experiment gives valid results (3)
He did repeats hence making it valid.
He had suitable interval of 5 degrees and 6 data to be able to compare and see the trend
The ph was the measurement of H+ in oxidative phosphorylation and hence the results should be valid
The critical value was more than the given value ( or vice versa) and hence there was no no significant difference in the mean
Autoimmune disease attacking nervous system (2)
Immune system attacks the cells of the nervous system i,e the neurons and since neurons are already differentiated, they cannot be replicated and hence the damage is permanent. The immune system does this by detecting the antigen of neurons as foreign.
Look at the figure and suggest how the autoimmune disease causes the slow movement of impulse? (2)
Myelin sheath is removed in the affected neuron and hence this stops the saltatory conduction from happening leading to leaks in the flow of action potential.
The symptoms only showed in MC and not the other one?(2)
1. Paralysis??
2. lack of reflex action?
How does the autoimmune disease cause change in neuromuscular junction? (2)
????
Explain and suggest the changes happening due to factors and type of respiration? (3)
The yeast is respiring anaerobically and rate is very fast
This leads to lack of glucose molecule and cumulation of ethanol.
The yeast starts converting ethanol into acetyl coA and at around 8h aerobic respiration starts
The CO2 production hits 0 at around 8h but rises after words due to decarboxylation of carbons in krebs cycle as coA enters Kreb.
The Nitrogen cycle (4)
Plant roots,
NO2- goes to NO3-
NO3- goes to N2 and
the last bacteria was in air
The enzyme diagram (4)
CO was non competitive inhibitor as it binds to alosteric site and this can change the shape of the active site
H was competitive inhibitor with N2 being the actual substrate
Iron and sulfur were prosthetic groups
Leghaemoglobin (2)
Point 1:- Has high affinity of oxygen and hence changes the rate of nitrogenous.
Point 2:- ???
What should you do to make sure that the culture is in best conditions for replication? (2)
Sterilize the area and make sure that the area doesn't contain any other microbes. Heat up the inoculating loop before culturing the bacteria
How are the insect tracheal increase surface area for gas exchange? (1)
They have a lot of spiracles and can removed tracheal fluid to increase the surface area for diffusion
How are fish gills adapted to increase the surface area for gas exchange? (1)
Gills have lamellae which increases surface area
Fill in the blank
Goblet cells, noradrenaline, diaphragm, forced
1
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#2
(Original post by john27000)
My answers are probably not that great so please contribute
1 a) circle the R group (1)
k
NH2---- C----COOH
Where k is the R group ( it was pretty big)
b) What does this conclude about the chemical properties of component X and leu?(1)
ans. leu is more soluble than component X/ leu is more polar than component X
c) 1.5cm away from origin (plotted on diagram) (3)
d) What material is used in the stationary phase (1)
ans. alluminium hydroxide or silica gel
e) Where is the exact location of photosynthetic pigments in the chloroplasts?(2)
ans. It is present in the photosystem of thylakoids
f) Difference between electrophoresis and chromatography (3)
Electrophoresis uses cathode and anode, chromatography doesnt
Electrophoresis uses aragose gel where as chromatography uses silica gel
Electrophoresis takes longer than chromatography
Now i don't know the order of questions so save me
Maths question 1:- 800% increase= 7.6x10^3 (2)
Maths question 2:- 13% (2)
Maths question 3:- hardy Weinberg 0.02% (3)
Maths question 4:- serial dilution ( how was that worth only 2 marks)
3750000
Protein structures:- secondary, quaternary, primary, tertiary (2)
What does this suggest about the antibody structure and what does the antibody binds to? (2)
Antibody binds to another molecule other than gliadin and hence the variable region is complimentary to another molecule
6 marker on the student measure heart rate and then calcualting student t test:- (6)
Same Significant figures throughout the table- making the student t test more reliable
Same time of the day, as the day goes by the temperature increases in the afternoon. rate of respiration is affected by temperature and hence affects the heart rate indirectly.
Ask for asthama- could produce anomalous result
Smaller intervals- every 200m making the data more accurate
Do repeats etc
Use suitable units in the table
What type of adaptation were the striped tiger furs? (1)
Physiological adaptation
6 marker on how striped tigers mutated from non striped:- (6)
Striped tigers were put under selection pressure and this led to a random mutation in the allele which gave the phenotype of striped tigers. As tigers have interspecific and intraspecific competition for food, the striped tigers were able to camouflage with the nature very well and hence had a higher success rate with their prey. This lead to out competing the non striped tigers and the striped tigers were able to survive and reproduce. Over several generations the population of non striped decreased and the allele frequency decrease of non striped decreased in the gene pool. This is also known as natural selection
Student doing experiment on effect of temperature on rate of respiration and evaluating if his experiment gives valid results (3)
He did repeats hence making it valid.
He had suitable interval of 5 degrees and 6 data to be able to compare and see the trend
The ph was the measurement of H+ in oxidative phosphorylation and hence the results should be valid
The critical value was more than the given value ( or vice versa) and hence there was no no significant difference in the mean
Autoimmune disease attacking nervous system (2)
Immune system attacks the cells of the nervous system i,e the neurons and since neurons are already differentiated, they cannot be replicated and hence the damage is permanent. The immune system does this by detecting the antigen of neurons as foreign.
Look at the figure and suggest how the autoimmune disease causes the slow movement of impulse? (2)
Myelin sheath is removed in the affected neuron and hence this stops the saltatory conduction from happening leading to leaks in the flow of action potential.
The symptoms only showed in MC and not the other one?(2)
1. Paralysis??
2. lack of reflex action?
How does the autoimmune disease cause change in neuromuscular junction? (2)
????
Explain and suggest the changes happening due to factors and type of respiration? (3)
The yeast is respiring anaerobically and rate is very fast
This leads to lack of glucose molecule and cumulation of ethanol.
The yeast starts converting ethanol into acetyl coA and at around 8h aerobic respiration starts
The CO2 production hits 0 at around 8h but rises after words due to decarboxylation of carbons in krebs cycle as coA enters Kreb.
The Nitrogen cycle (4)
Plant roots,
NO2- goes to NO3-
NO3- goes to N2 and
the last bacteria was in air
The enzyme diagram (4)
CO was non competitive inhibitor as it binds to alosteric site and this can change the shape of the active site
H was competitive inhibitor with N2 being the actual substrate
Iron and sulfur were prosthetic groups
Leghaemoglobin (2)
Point 1:- Has high affinity of oxygen and hence changes the rate of nitrogenous.
Point 2:- ???
What should you do to make sure that the culture is in best conditions for replication? (2)
Sterilize the area and make sure that the area doesn't contain any other microbes. Heat up the inoculating loop before culturing the bacteria
My answers are probably not that great so please contribute
1 a) circle the R group (1)
k
NH2---- C----COOH
Where k is the R group ( it was pretty big)
b) What does this conclude about the chemical properties of component X and leu?(1)
ans. leu is more soluble than component X/ leu is more polar than component X
c) 1.5cm away from origin (plotted on diagram) (3)
d) What material is used in the stationary phase (1)
ans. alluminium hydroxide or silica gel
e) Where is the exact location of photosynthetic pigments in the chloroplasts?(2)
ans. It is present in the photosystem of thylakoids
f) Difference between electrophoresis and chromatography (3)
Electrophoresis uses cathode and anode, chromatography doesnt
Electrophoresis uses aragose gel where as chromatography uses silica gel
Electrophoresis takes longer than chromatography
Now i don't know the order of questions so save me
Maths question 1:- 800% increase= 7.6x10^3 (2)
Maths question 2:- 13% (2)
Maths question 3:- hardy Weinberg 0.02% (3)
Maths question 4:- serial dilution ( how was that worth only 2 marks)
3750000
Protein structures:- secondary, quaternary, primary, tertiary (2)
What does this suggest about the antibody structure and what does the antibody binds to? (2)
Antibody binds to another molecule other than gliadin and hence the variable region is complimentary to another molecule
6 marker on the student measure heart rate and then calcualting student t test:- (6)
Same Significant figures throughout the table- making the student t test more reliable
Same time of the day, as the day goes by the temperature increases in the afternoon. rate of respiration is affected by temperature and hence affects the heart rate indirectly.
Ask for asthama- could produce anomalous result
Smaller intervals- every 200m making the data more accurate
Do repeats etc
Use suitable units in the table
What type of adaptation were the striped tiger furs? (1)
Physiological adaptation
6 marker on how striped tigers mutated from non striped:- (6)
Striped tigers were put under selection pressure and this led to a random mutation in the allele which gave the phenotype of striped tigers. As tigers have interspecific and intraspecific competition for food, the striped tigers were able to camouflage with the nature very well and hence had a higher success rate with their prey. This lead to out competing the non striped tigers and the striped tigers were able to survive and reproduce. Over several generations the population of non striped decreased and the allele frequency decrease of non striped decreased in the gene pool. This is also known as natural selection
Student doing experiment on effect of temperature on rate of respiration and evaluating if his experiment gives valid results (3)
He did repeats hence making it valid.
He had suitable interval of 5 degrees and 6 data to be able to compare and see the trend
The ph was the measurement of H+ in oxidative phosphorylation and hence the results should be valid
The critical value was more than the given value ( or vice versa) and hence there was no no significant difference in the mean
Autoimmune disease attacking nervous system (2)
Immune system attacks the cells of the nervous system i,e the neurons and since neurons are already differentiated, they cannot be replicated and hence the damage is permanent. The immune system does this by detecting the antigen of neurons as foreign.
Look at the figure and suggest how the autoimmune disease causes the slow movement of impulse? (2)
Myelin sheath is removed in the affected neuron and hence this stops the saltatory conduction from happening leading to leaks in the flow of action potential.
The symptoms only showed in MC and not the other one?(2)
1. Paralysis??
2. lack of reflex action?
How does the autoimmune disease cause change in neuromuscular junction? (2)
????
Explain and suggest the changes happening due to factors and type of respiration? (3)
The yeast is respiring anaerobically and rate is very fast
This leads to lack of glucose molecule and cumulation of ethanol.
The yeast starts converting ethanol into acetyl coA and at around 8h aerobic respiration starts
The CO2 production hits 0 at around 8h but rises after words due to decarboxylation of carbons in krebs cycle as coA enters Kreb.
The Nitrogen cycle (4)
Plant roots,
NO2- goes to NO3-
NO3- goes to N2 and
the last bacteria was in air
The enzyme diagram (4)
CO was non competitive inhibitor as it binds to alosteric site and this can change the shape of the active site
H was competitive inhibitor with N2 being the actual substrate
Iron and sulfur were prosthetic groups
Leghaemoglobin (2)
Point 1:- Has high affinity of oxygen and hence changes the rate of nitrogenous.
Point 2:- ???
What should you do to make sure that the culture is in best conditions for replication? (2)
Sterilize the area and make sure that the area doesn't contain any other microbes. Heat up the inoculating loop before culturing the bacteria
Adaptation is either Physical or Anatomical not Physiological
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#3
Top part is R group
(Original post by jstubbs99)
It is aluminium oxide (Al2O3) not hydroxide for the material
Adaptation is either Physical or Anatomical not Physiological
It is aluminium oxide (Al2O3) not hydroxide for the material
Adaptation is either Physical or Anatomical not Physiological
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#4
I don't remember the last question you listed, where in the paper was it, hopefully I'm just having a forgetful moment xD
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#6
(Original post by fw431)
I don't remember the last question you listed, where in the paper was it, hopefully I'm just having a forgetful moment xD
I don't remember the last question you listed, where in the paper was it, hopefully I'm just having a forgetful moment xD
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#7
(Original post by student0299)
Yeah I don't remember seeing this either :// did I miss out a question?!
Yeah I don't remember seeing this either :// did I miss out a question?!
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#8
Hardy-Weinberg was 2% and pretty certain it was 11% and not 13% along with 8550 kJm-2yr-2 (since it was 800% greater than 950).
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#9
Other answers can be found at this unofficial markscheme:
https://docs.google.com/document/d/1...it?usp=sharing
https://docs.google.com/document/d/1...it?usp=sharing
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#10
q^2 = 1/10000
q = 0.01
p = 1 - 0.01 = 0.99
2pq = 2 x 0.99 x 0.01 = 0.0198
0.0198 * 100 = 1.98% but 1 sig fig so 2%
q = 0.01
p = 1 - 0.01 = 0.99
2pq = 2 x 0.99 x 0.01 = 0.0198
0.0198 * 100 = 1.98% but 1 sig fig so 2%
1
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(Original post by Tuffyandtab)
Hardy-Weinberg was 2% and pretty certain it was 11% and not 13% along with 8550 kJm-2yr-2 (since it was 800% greater than 950).
Hardy-Weinberg was 2% and pretty certain it was 11% and not 13% along with 8550 kJm-2yr-2 (since it was 800% greater than 950).
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#12
(Original post by student0299)
Yeah I don't remember seeing this either :// did I miss out a question?!
Yeah I don't remember seeing this either :// did I miss out a question?!
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#14
(Original post by jstubbs99)
It is aluminium oxide (Al2O3) not hydroxide for the material
Adaptation is either Physical or Anatomical not Physiological
It is aluminium oxide (Al2O3) not hydroxide for the material
Adaptation is either Physical or Anatomical not Physiological
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#16
(Original post by Haydn77)
Could you definitely have physical? Cos I put that and then was worried that I got that one wrong
Could you definitely have physical? Cos I put that and then was worried that I got that one wrong
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#17
(Original post by Haydn77)
It was like right at the end of the paper before the word fill
It was like right at the end of the paper before the word fill
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#18
What do you think an C grade would be. I think I got like 30/70 in this paper which is really bad. I just didn't understand what the questions were asking me
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#19
For the fish gills one I couldn't remember the name lamellae and thought it would be stupid to write 'they're shaped like tentacles' or something so I put 'gills are arranged in an arc' then drew a little picture haha. Does anyone know if drawings get marks for a question like that, on the off chance!?!
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#20
exactly same here and i also need a C 
(Original post by unknown.123)
What do you think an C grade would be. I think I got like 30/70 in this paper which is really bad. I just didn't understand what the questions were asking me
What do you think an C grade would be. I think I got like 30/70 in this paper which is really bad. I just didn't understand what the questions were asking me
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