Hey guys! This is the unofficial mark scheme created by @menna123
and I. Menna is awesome!!!
If you have any changes to make then feel free to type it and we'll edit it!
Also, thanks @danielwinstanley
for helping to type out all the marks for each question and construct a more coherent mark scheme!!
1. what is memory? (2 marks)
the storage (1) and retrieval of information (1)
1ii. What is the part of the brain responsible for memory? (1 mark)
2. Why would John still want to undertake the surgery? (2 marks)
- benefits outweighs the risks
- if he does not have the surgery it can spread to the rest of his brain.
- The benefits of the surgery outweigh the consequence of losing some of his memory.
- John's perception of the risk is low because he does not mind losing his memory.
3. How does Judith remember to play the piano? (3 marks)
- First time she plays it is in short term memory, and she needs to establish new neurone pathways in the brain.
- with repetition and reinforcement moves into the long term memory and this info can be retrieved
- neurone pathways form when she learns the skill
- as she reinforces and repeats the skill the neuron pathways travel down more strengthened.
4. When do human cells respire anaerobically (1 mark)
during vigorous exercise
5. What two things are needed to make amino acids? (2 marks)
nitrates and glucose.
6. What do amino acids make when joined together? (1 mark)
7. How does water travel through the roots? (1 mark)
8. Why is oil stored on top of the glucose/starch solution? (2 marks)
It means that no oxygen enters the solution as fermentation requires anaerobic respiration, and the presence of oxygen would mean that it would respire aerobically and fermentation would not be able to take place.
8ii. Conclusions (4 marks)
any valid conclusion based on the data is correct, links to respiration
- At 45 degrees the rate of respiration is high due to high rate of reaction so lots of CO2 bubbles are released but would then decrease due to high temperatures denaturing the active site of the enzyme. This means that the enzyme can no longer respire anaerobically and release CO2 as the cells have been killed.
8iii. Problem with measuring CO2 bubbles (1 mark)
- it's difficult to observe and see what qualifies as a bubble
- the bubbles of CO2 could be different volumes
- human error as not measured by a computer (such as she may miscounted, might miss a bubble)
8iiii. Another way to measure CO2 volume (1 mark)
- Measure the volume of carbon dioxide produced in a set time period
- Measure the time taken to produce a set amount of gas
- Gas syringe
9. Ticking boxing question for respiration (3 marks)
Aerobic respiration - Needs oxygen
Both aerobic and anaerobic respiration - need glucose
Anaerobic respiration - releases lactic acid
Aerobic respiration - in the mitochondria
Aerobic respiration - releases carbon dioxide
10. Graph question for limiting factor of photosynthesis (1 mark)
when graph flattened out. Plot the X anywhere when the graph plateaus (light is no longer increasing)
11. Six marker on dunes (6 marks)
Define each and explain how it would be useful.
12. Six marker on star fish (6 marks)
- human nervous system = CNS, brain and spinal chord. Joined to body via peripheral nervous system
- motor and sensory neurons. I said that the centre of the starfish was its CNS and it too has neuron pathways and receptors.
- They both have receptors (light receptor in the starfish and receptors in humans)
- Human nervous system has a processing centre to modify reflexes and for higher thought whereas starfish rely on simple reflexes.
- Human nervous system has synapses (gaps) whereas starfish do not.
- Human nervous system is made out of billions of neurons.
13. Six marker on amino acid and proteins (6 marks)
DNA is a double helix of paired bases a-t c-g, genetic code for production of proteins. Triplet code codes for one amino acid. Amino acids joined to make proteins etc. Different base would mean different coding of amino acid, meaning different sequence of amino acid a different/faulty protein is made. (Could refer to mRNA and ribosomes but probably not necessary in gaining 6 marks).
14. Name for when a plant grows towards light (1 mark)
14ii. Why do plants grow towards light (1 mark)
To increase chances of survival as they can have more light energy for photosynthesis.
15. Question on child with cystic fibrosis (1 mark)
baby is unlikely to have cystic fibrosis
15i. What doctor would do with information (1 mark)
more genetic tests/monitor child
16. Calculations- 0.0012% (2 marks) and 9000 (1 mark)
17. Question on why mucus was sticker (2 marks)
faulty DNA means that chloride ions (dissolved in water) cannot move from higher to lower concentration in membrane due to the fact that cystic fibrosis is a genetic disorder of the cell membranes. Meaning that the mucus stays in the region of higher concentation, further increasing the concentation of chloride ions, making mucus stickier
18. Order for serotonin concentration (3 marks) (not confirmed)- potentially (C) A B E D
but the order was:
1)more serotonin is released from the first neuron.
2) increase in serotonin concentration
3) more serotonin binds to next membrane
4) more impulses generated
20. What can you gather from results on ecstasy from graph (1 mark)
Ecstasy with psychotherapy is more effective than just psychotherapy
20ii.Question on increasing confidence in ecstasy test results (2 marks)
- use a bigger sample
- conduct over a longer period of time
- peer review and other scientists do it to make it reproducible.