Aqa Combined Biology Gcse Watch

Ak40
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Anyone with answers to Aqa Biology exam combined science?
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Q. What is the drug digitalis made from? (1 mark)
a. Bacteria
b. Foxglove
c. Mould
d. Willow
A. b (Foxglove)

Q. Why do people using beta blockers feel out of breath during exercise? (6 marks)
A. Points to include to get 6 marks:
-Beta blockers prevent your heart rate from increasing as you exercise.
-This limits the supply of oxygenated blood to cells.
-Which is needed for respiration.
-This could lead to higher levels of anaerobic respiration/oxygen debt/cells need more oxygen.
-Body tries to get more oxygen through increasing breathing rate.
-This leads to feelings of shortness of breath.
[if someone could write a full marks answer for everyone we would appreciate it...]

Q. What is the size of the real image under the microscope? The magnification is x50 and the image is size 43mm under the magnification. Give in micrometres (2 marks?)
A. 43 divided by 50 = 0.86mm (real size image in millimetres), 0.86 times 1000 = 860um (real size in micrometres)

Q. Find the value of X in this table. Give your answer to 2sf. [insert table - cardiovascular output and heart rate with an X for stroke volume rate] (2 marks)
A. You had to divide something by something and the answer was 53.8 but rounded to 2sf was 54 (2sf)

Q. Why are nitrate ions essential for plants to survive?
A. Main points for 4 marks:
-Plants need nitrogen (found in nitrates) for:
-Amino acids
-DNA
-ATP
-Chlorophyll

Q. Describe the graph with different stages of bacteria growth. [insert graph with an exponential growth, then peak, then slow downfall]
A. Stage A: The Bacteria number is low because they have not had time to divide and reproduce.
Stage B: The Bacteria is growing exponentially due to no limiting factors.
Stage C: The Bacteria has reached a peak due to it having a limiting factor.
Stage D: The Bacteria has used up all of its culture and is therefore dying due to no nutrition.

Q. The single celled organism [insert picture of small cube] can get all its nutrients through diffusion, however the multi-cellular organism can not [insert picture of big cube]. Why is this? [5 marks]
A. -work out the surface area to volume ratio for both; the smaller cube as a greater surface area to volume ratio as its a single celled organism (cannot remember what it was I think it was bacteria or some ****) meaning sufficient substances diffuse in and out of the cell meeting the demand of the cell
-The bigger cube (multi cellular organism) will have a lower surface area to volume ratio however you could mention that this is offset by the surfaces being adapted for substance exchange.

Q. How to return the air bubble to the front of the tube?
A. Turn the tap [this is not certain but most people put it]

Q. What indicator is used in the test for starch?
A. Iodine

Q. What indicator is used in the test for sugar?
A. Benedict's solution

Q. What does the partially permeable tubing and water represent? [insert picture of partially permeable tubing surrounded with water at body temperature]
A. Small intestine and blood


This is from the unofficial markscheme thread
(Original post by Ak40)
Anyone with answers to Aqa Biology exam combined science?
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