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2017 AQA AS BIOLOGY 7401/2 Paper 2|BRAND NEW EXAM QUESTIONS AND CORRECT AND CORRECT VERIFIED ANSWERS ALL GRADED A+|GUARANTEED SUCCESS|LATEST UPDATE $10.49
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2017 AQA AS BIOLOGY 7401/2 Paper 2|BRAND NEW EXAM QUESTIONS AND CORRECT AND CORRECT VERIFIED ANSWERS ALL GRADED A+|GUARANTEED SUCCESS|LATEST UPDATE
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2017 AQA AS BIOLOGY 7401/2 Paper 2
2017 AQA AS BIOLOGY 7401/2 Paper 2|BRAND NEW EXAM QUESTIONS AND CORRECT AND CORRECT VERIFIED ANSWERS ALL GRADED A+|GUARANTEED SUCCESS|LATEST UPDATE
Glycogen and cellulose are both carbohydrates. Describe two differences between the structure of a cellulose molecule and a glycogen molecu...
2017 AQA AS BIOLOGY 7401/2 Paper 2|BRAND NEW
EXAM QUESTIONS AND CORRECT AND CORRECT
VERIFIED ANSWERS ALL GRADED A+|GUARANTEED
SUCCESS|LATEST UPDATE
Glycogen and cellulose are both carbohydrates. Describe two differences between
the structure of a cellulose molecule and a glycogen molecule. (2) - ANSWER-✔1.
cellulose is made up of beta glucose monomers and glycogen is made up of alpha
glucose monomers
2. cellulose has straight chains and glycogen is branched
3. glycogen has 1-4 and 1-6 glycosidic bonds but cellulose has only 1-4 glycosidic
bonds
Starch is a carbohydrate often stored in plant cells. Describe and explain two
features of starch that make it a good storage molecule. (2) - ANSWER-✔1. it is
insoluble in water so doesn't affect water potential
2. branched/coiled so makes molecule compact
3. polymer of alpha glucose so provides glucose for respiration
4. branched so more ends for fast breakdown/enzyme action
5. large molecule so can't cross cell membrane
Tick () the box that identifies the test which would be used to show the presence of
starch. (1) - ANSWER-✔1. iodine/potassium iodide
2. 4th box down
One population had a high-starch diet and the other population had a low-starch
diet.
Describe what their results show. (3) - ANSWER-✔1. low starch, fewer copies
2. ranges overlap almost completely
3. the mode/highest percentage for low starch is 4 copies amd for high starch is 6
4. the range/spread of data is greater with high starch
, What is the difference between males and females in the fall in mean concentration
of protein in blood plasma between 60 and 95 years? (1) - ANSWER-✔1. 6 g/dm
cubed
Use Figure 4 to calculate the rate of change of the mean concentration of protein in
the blood plasma of males between the ages of 60 and 95. Show your working. (2) -
ANSWER-✔1. 0.14
2. differences divide by number of years
What can you conclude from Figure 4 about the effect of ageing on the mean
concentration of protein in the blood plasma in males and females? (2) - ANSWER-
✔1. protein content decreases with age and decreases more in females
2. difference only significant at 95 years because SDs don't overlap
The scientists measured the absorption of each sample of blood plasma using a
colorimeter. They used a calibration curve to find the concentration of protein in
samples of blood plasma. Describe how the scientists could obtain data to produce a
calibration curve and how they would use the calibration curve to find the
concentration of protein in a sample of blood plasma. (3) - ANSWER-✔1. produce
known concentrations of protein
2. measure absorbance of each concentration
OR
measure each concentration with colorimeter
3. plot a graph of absorbance on y axis against concentration on x axis and draw
curve
4. use absorbance of sample to find protein concentration from curve
Older people are more likely to suffer from infectious diseases. Suggest how this
may be linked to the decrease in the mean concentration of protein in the blood as
people get older. (1) - ANSWER-✔1. lower protein concentration suggests fewer
antibodies
Explain how changes in the shape of haemoglobin result in the S-shaped (sigmoid)
oxyhaemoglobin dissociation curve for HbA. (2) - ANSWER-✔1. first oxygen binds to
haemoglobin causing change in shape
2. shape allows more oxygen to bind to greater saturation
OR
Cooperative binding
At birth 98% of the haemoglobin is HbF. By the age of 6 months, the HbF has usually
completely disappeared from the baby's blood and been replaced by HbA. Use
Figure 5 to explain why this change is an advantage for the baby. (2) - ANSWER-✔1.
HbA has a lower affinity for oxygen at low partial pressures
OR
HbA has a lower affinity for oxygen at pp found in tissues
2. easier unloading of oxygen for aerobic respiration
, The scientists concluded that treatment with hydroxyurea would increase the
concentration of oxygen in the blood of babies with SCD. Suggest how Figure 5 and
Table 1 support this conclusion. (3) - ANSWER-✔1. a large/significant increase in HbF
2. HbF has a higher affinity for oxygen
3. higher proportion of HbF in blood so more oxygen carried
OR
more oxygen carried after treatment
Calculate the ratio of mean stomatal diameter of leaves treated with PS3 to those
treated with ABA. (2) - ANSWER-✔1. answer = 1.48
2. PS3 = 7.1 and ABA = 4.8
3. 7.1/4.8 = 1.479...
ABA is a substance that some plant species produce when little water is available.
Explain why producing ABA may help these species survive in dry conditions. (2) -
ANSWER-✔1. causes less stomatal opening so less transpiration/less evaporation
2. more water available for photosynthesis/metabolism
Many species of plants can be infected by powdery mildew which is spread by
microscopic spores in the air. Suggest how treatment with Lam13 might protect
plants against powdery mildew infection. (1) - ANSWER-✔1. closes the stomata so
fewer/no spores enter leaf
NMO is a disease that leads to damage to nerve cells in the spinal cord. A person
with NMO produces anti-AQP4 antibody that attacks only these nerve cells. Explain
why the anti-AQP4 antibody only damages these cells. (4) - ANSWER-✔1. antibody
has a specific tertiary structure
2. has binding site/variable region that only binds to/ complementary to one antigen
3. antigen to this antibody only found on these nerve cells
4. antibody forms antigen-antibody complex with these nerve cells
A scientist suggested that the concentration of anti-AQP4 antibody in a person's
blood could be used to predict the number of vertebrae surrounding damaged nerve
cells they are likely to have. Use Figure 7 to suggest reasons why this suggestion
might not be valid. (3) - ANSWER-✔1. only 20 in study
OR
only one study
2. for some concentrations of antibody there is a range in the number of vertebrae
surrounding damaged nerve cells
3. no stats test
4. correlation is weak
Use this information and your knowledge of antigen-antibody complexes to suggest
how this monoclonal antibody prevents anti-AQP4 damaging nerve cells (2) -
ANSWER-✔1. the monoclonal antibody binds to nerve cell antigen so less/no anti-
AQP4 can bind
OR
, monoclonal antibody forms antigen-antibody complex with nerve cell antigen so
less/no anti - AQP4 can bind
2. when monoclonal antibody binds it doesn't cause damage to nerve cell
Describe the cohesion-tension theory of water transport in the xylem. (5) -
ANSWER-✔1. water lost from leaf because of transpiration/evaporation of
water/diffusion from mesophyll/leaf cells
2. lowers water potential of leaf
3. water pulled up xylem creating tension
4. water molecules cohere/stick together by hydrogen bonds
5. forming a continuous, unbroken column
6. adhesion of water molecules to walls of xylem
What 3 things had happened by the end of the 19th Century? - ANSWER-✔- The
19th Century when philosophers, physiologists and physicians applied the scientific
method to study the mind.
1) Psychology became defined as 'the science of mental life, both of its phenomena
and their conditions'.
2) Introspection was developed to expose the mind to scientific research.
3) First experimental psychology labs appeared in universities.
Who is classed as the father of experimental psychology? - ANSWER-✔- Wundt,
opened the first psychology lab in Germany and developed introspection as a
method of studying the mind.
- First person to be called a psychologist.
Define 'introspection'. - ANSWER-✔- The first systematic experimental attempt to
study the mind by breaking up awareness into basic structures of thoughts, images
and sensations.
- This isolation is called structuralism.
What is Wundt's contribution to psychology? - ANSWER-✔1) Wrote the first
psychology textbook.
2) Set up the first experimental psychology lab.
3) Used the scientific method to study the structure of sensation and perception.
4) Showed that introspection could be used to study mental states.
What is a strength and a limitation of Wundt's methods? - ANSWER-✔- Strength:
Some of his methods are scientific, recorded the introspections in a controlled lab
environment, also used standardised procedures.
- Limitation: Some aspects of his research are not scientific, relied on participants
self-reporting their 'private' mental processes, subjective data and cannot establish
general principles.
In terms of psychology emerging as a science, what key things happened in the
1900s? - ANSWER-✔- Early behaviourists (e.g. Watson;1913) rejected introspection
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