1.
State what is meant by a resting potential.
[1 mark]
- about −70 mV, Na⁺/K⁺ pump, more K⁺ leak
JD SCIENCE
Control, coordination and homeostasis
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 an action potential.
[1 mark]
- depolarisation then repolarisation
3.
State what is meant by saltatory conduction.
[1 mark]
- jumps between nodes of Ranvier
4.
State what is meant by a synapse.
[1 mark]
- neurotransmitter, summation, unidirectional
5.
State what is meant by negative feedback.
[1 mark]
- reverses a change
6.
State what is meant by insulin and glucagon.
[1 mark]
- from islets of the pancreas
7.
State what is meant by ADH.
[1 mark]
- from pituitary, acts on collecting duct
8.
State what is meant by the kidney nephron.
[1 mark]
- ultrafiltration, selective reabsorption, loop of Henle
9.
State what is meant by IAA / auxin.
[1 mark]
- uneven distribution causes tropisms
10.
State what is meant by the sliding-filament theory.
[1 mark]
- actin and myosin, tropomyosin, calcium, ATP
11.
Devon is asked about a resting potential in a Edexcel Biology paper.
(a) [2 marks]
- inside negative
(b) [3 marks]
- ready to fire
12.
Devon is asked about an action potential in a Edexcel Biology paper.
(a) [2 marks]
- all-or-nothing
(b) [3 marks]
- voltage-gated channels
13.
Devon is asked about saltatory conduction in a Edexcel Biology paper.
(a) [2 marks]
- myelin
(b) [3 marks]
- faster
14.
Devon is asked about a synapse in a Edexcel Biology paper.
(a) [2 marks]
- drugs can mimic or block
(b) [3 marks]
- fatigue if transmitter runs out
15.
Devon is asked about negative feedback in a Edexcel Biology paper.
(a) [2 marks]
- blood glucose, temperature
(b) [3 marks]
- keeps conditions stable
16.
Devon is asked about insulin and glucagon in a Edexcel Biology paper.
(a) [2 marks]
- antagonistic
(b) [3 marks]
- glycogenesis vs glycogenolysis
17.
Impulse speed 1.2 m in 0.015 s
[3 marks]
- Final answer: 80 m/s
18.
A neurone diameter doubles (qualitative). Effect on speed
[3 marks]
- Final answer: faster (less resistance)
19.
GFR idea: 125 cm³/min. Volume in 1 hour
[3 marks]
- Final answer: 7.5 dm³
20.
Blood glucose 5.0 to 7.5. Percentage increase
[3 marks]
- Final answer: 50%
21.
Sarcomere 2.4 µm to 2.0 µm. Percentage shortening
[3 marks]
- Final answer: 16.7%
22.
A reflex path is 1.8 m at 60 m/s. Time
[3 marks]
- Final answer: 0.030 s
23.
Devon carries out a Edexcel-style required practical linked to control, coordination and homeostasis. This is a typical Edexcel 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.
Devon carries out collecting valid data for control, coordination and homeostasis. This is a typical Edexcel 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.
Devon carries out drawing a graph for control, coordination and homeostasis. This is a typical Edexcel 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.
Devon carries out evaluating a method about control, coordination and homeostasis. This is a typical Edexcel 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 a resting potential with an action potential.
[4 marks]
- about −70 mV, Na⁺/K⁺ pump, more K⁺ leak
- depolarisation then repolarisation
- give one linked difference
28.
Compare an action potential with saltatory conduction.
[4 marks]
- depolarisation then repolarisation
- jumps between nodes of Ranvier
- give one linked difference
29.
Compare saltatory conduction with a synapse.
[4 marks]
- jumps between nodes of Ranvier
- neurotransmitter, summation, unidirectional
- give one linked difference
30.
Compare a synapse with negative feedback.
[4 marks]
- neurotransmitter, summation, unidirectional
- reverses a change
- give one linked difference
31.
Apply your knowledge of ADH to this situation: more aquaporins, less urine
[3 marks]
- more aquaporins, less urine
32.
Apply your knowledge of the kidney nephron to this situation: water potential gradient
[3 marks]
- water potential gradient