1.
State what is meant by surface area to volume ratio.
[1 mark]
- decreases as size increases
JD SCIENCE
Organisms exchange substances with their environment
Indicative marking points. Award marks for equivalent scientific or mathematical wording. Do not issue this sheet with the student worksheet.
2.
State what is meant by Fick's law.
[1 mark]
- rate ∝ SA × difference / thickness
3.
State what is meant by the alveolus.
[1 mark]
- thin, large SA, good blood supply, moist
4.
State what is meant by the counter-current system in fish.
[1 mark]
- water and blood flow opposite ways
5.
State what is meant by the cardiac cycle.
[1 mark]
- atria, ventricles, valves
6.
State what is meant by tissue fluid formation.
[1 mark]
- high hydrostatic pressure at arterial end
7.
State what is meant by haemoglobin dissociation.
[1 mark]
- S-shaped curve
8.
State what is meant by xylem transport.
[1 mark]
- cohesion-tension
9.
State what is meant by phloem translocation.
[1 mark]
- mass flow from source to sink
10.
State what is meant by the Bohr effect.
[1 mark]
- extra CO₂ lowers haemoglobin's affinity for oxygen
11.
Amira is asked about surface area to volume ratio in a AQA Biology paper.
(a) [2 marks]
- why large organisms need exchange systems
(b) [3 marks]
- diffusion alone is too slow
12.
Amira is asked about Fick's law in a AQA Biology paper.
(a) [2 marks]
- alveoli and gills
(b) [3 marks]
- steep gradient maintained by blood and ventilation
13.
Amira is asked about the alveolus in a AQA Biology paper.
(a) [2 marks]
- gas exchange
(b) [3 marks]
- elastin for recoil
14.
Amira is asked about the counter-current system in fish in a AQA Biology paper.
(a) [2 marks]
- gradient along the whole lamella
(b) [3 marks]
- more oxygen extracted
15.
Amira is asked about the cardiac cycle in a AQA Biology paper.
(a) [2 marks]
- pressure changes open/close valves
(b) [3 marks]
- SAN is the pacemaker
16.
Amira is asked about tissue fluid formation in a AQA Biology paper.
(a) [2 marks]
- plasma out, some return at venous end / lymph
(b) [3 marks]
- proteins stay in capillary
17.
SA of a cube side 3 cm
[3 marks]
- Final answer: 54 cm²
18.
SA:V of that cube
[3 marks]
- Final answer: 2 : 1
19.
Cardiac output 5.6 dm³/min, HR 70. Stroke volume
[3 marks]
- Final answer: 80 cm³
20.
Ventilation rate 12 /min × 0.5 dm³
[3 marks]
- Final answer: 6 dm³/min
21.
A capillary is 1 µm thick. Time idea: diffusion path compared with 10 µm
[3 marks]
- Final answer: 10 times shorter
22.
Heart rate rises from 60 to 150. Percentage increase
[3 marks]
- Final answer: 150%
23.
Amira carries out a AQA-style required practical linked to exchange and transport. This is a typical AQA required-practical style question.
(a) [2 marks]
- Independent: the independent variable for this topic
- Dependent: the measured outcome
(b) [2 marks]
- keep all other variables constant
- so the test is fair / only one variable is changed
(c) [2 marks]
- repeat and calculate a mean / use a tighter method
24.
Amira carries out collecting valid data for exchange and transport. This is a typical AQA required-practical style question.
(a) [2 marks]
- Independent: a chosen factor
- Dependent: a quantitative measurement
(b) [2 marks]
- calibrated instrument
- so the test is fair / only one variable is changed
(c) [2 marks]
- systematic error from zero error
25.
Amira carries out drawing a graph for exchange and transport. This is a typical AQA required-practical style question.
(a) [2 marks]
- Independent: x-variable
- Dependent: y-variable
(b) [2 marks]
- same scale / same apparatus
- so the test is fair / only one variable is changed
(c) [2 marks]
- not drawing a line of best fit through the trend
26.
Amira carries out evaluating a method about exchange and transport. This is a typical AQA required-practical style question.
(a) [2 marks]
- Independent: method change
- Dependent: precision / accuracy
(b) [2 marks]
- same sample size
- so the test is fair / only one variable is changed
(c) [2 marks]
- too few repeats
27.
Compare surface area to volume ratio with Fick's law.
[4 marks]
- decreases as size increases
- rate ∝ SA × difference / thickness
- give one linked difference
28.
Compare Fick's law with the alveolus.
[4 marks]
- rate ∝ SA × difference / thickness
- thin, large SA, good blood supply, moist
- give one linked difference
29.
Compare the alveolus with the counter-current system in fish.
[4 marks]
- thin, large SA, good blood supply, moist
- water and blood flow opposite ways
- give one linked difference
30.
Compare the counter-current system in fish with the cardiac cycle.
[4 marks]
- water and blood flow opposite ways
- atria, ventricles, valves
- give one linked difference
31.
Apply your knowledge of haemoglobin dissociation to this situation: cooperative binding
[3 marks]
- cooperative binding
32.
Apply your knowledge of xylem transport to this situation: transpiration pull
[3 marks]
- transpiration pull