Co-ordination & Response | Edexcel GCSE Biology: Combined Science Paper 1 2018

1a

3 marks

Neurones such as the one shown in Figure 1 form part of the nervous system.

neuron

Figure 1

(i)

Name structures A and B.

Structure A ________________________

Structure B ________________________

(2)

(ii)

Name the method by which the axon transmits information.

(1)

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1b

2 marks

Describe the role of the myelin sheath surrounding the axon.

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1c

4 marks

Humans have reflexes.

Describe the route of an impulse through a reflex arc.

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1a

3 marks

Figure 1 shows a neurone found in the human nervous system. 2-4-edexcel-gcse-2-4h-sq-q4-neurone

Figure 1

(i)

State the name of the type of neurone seen in Figure 1 and describe its role in the nervous system.

(2)

(ii)

Label the dendrites on Figure 1.

(1)

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1b

5 marks

The nervous system contains important structures called synapses.

Explain how a signal is transmitted at a synapse.

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1c

5 marks

Some painkillers work by reducing the ability of synapses to transmit signals.

One scientist investigated the effect of different painkillers on the amount of pain felt by the patient. They tested paracetamol, ibuprofen and a placebo (sugar tablet containing no medication).

The results are shown in Figure 2 below. 2-4-edexcel-gcse-2-4h-sq-q4c-painkillers

Figure 2

(i)

State why the scientist decided to use a placebo in the experiment.

(1)

(ii)

A student concluded that paracetamol was the most effective painkiller.

Evaluate this conclusion.

(4)

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2a

6 marks

The human nervous system is responsible for detecting and responding to changes in our environment.

Describe how impulses in the reflex arc are transmitted in order to decrease the chances of getting hurt when accidentally touching a hot saucepan.

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2b

7 marks

Two students decided to investigate the speed of transmission of electrical impulses in the nervous system.

They decided to test how caffeine affected their reaction times. Student A drank a 330ml caffeinated sports drink while Student B drank a 330ml glass of water. They tested their reaction times every 5 minutes by dropping a ruler between their fingers and timing how long it took to catch the ruler.

The results of their experiment are shown in Table 1 below.

Table 1

Time after drinking caffeinated drink (mins)	Reaction time time (s)
Time after drinking caffeinated drink (mins)	Student A	Student B
0	0.16	0.16
5	0.15	0.16
10	0.13	0.15
15	0.11	0.12
20	0.09	0.11
25	0.10	0.10
30	0.11	0.10
35	0.14	0.12
40	0.18	0.17
45	0.18	0.17
50	0.18	0.18

(i)

Plot a graph of these results.

(5)

(ii)

The caffeinated sports drink manufacturer wants to advertise the effects of their sports drink on reaction time.

Give two improvements that could be made to this experiment to make the results more reliable.

(2)

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2c

5 marks

Impulses in neurones in the reflex arc can travel at 120 metres per second.

The sensory neurone in a single reflex arc is 76mm long.

(i)

Calculate the time an impulse takes to travel the length of this sensory neurone.

Use the equation:

speed = \frac{distance}{time}

(3)

(ii)

Multiple sclerosis (MS) is an autoimmune condition, caused when the body mistakes its own cells for foreign substances and this can trigger an immune response. The outcome of this is that the immune system attacks the nerve cells, and consequently the myelin sheath in the brain and nervous system becomes damaged.

Explain the role of the myelin sheath and suggest why people with MS might have slower reactions than people without MS.

(2)

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1a

1 mark

Figure 1 shows the structures of two neurones, A and B.

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Figure 1

Identify the kind of neurone that Neurone A is.

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1b

1 mark

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Identify the destination of the impulse carried by Neurone B.

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1c

3 marks

The boxes in Figure 2 show the structures and impulses that form part of a processed (voluntary) response. The stimulus is a person tapping another person on the shoulder. The second person decides to turn around (to see who tapped them on the shoulder) as their response.

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Figure 2

Place the boxes from Figure 2 into chronological order to describe the pattern of events in a processed response. The first one has been completed for you.

Sequential number	Event / organ
1.	Stimulus
2.
3.
4.
5.
6.
7.
8.
9.

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1d

2 marks

Describe two features of a processed response that distinguish it from a reflex response.

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☐	A	Central neurones, peripheral neurones, and relay neurones.
☐	B	Motor neurones, sensory neurones, and peripheral neurones.
☐	C	Sensory neurones, relay neurones, and motor neurones.
☐	D	Relay neurones, central neurones, and sensory neurones.

animal	number of neurones in the brain
lobster	1.0 × 10⁵
frog	1.6 × 10⁷
rat	2.0 × 10⁸
human	8.6 × 10¹⁰

student	reaction time in milliseconds
1	245
2	200
3	210
4	215
5	225

☐	A	200 milliseconds
☐	B	210 milliseconds
☐	C	215 milliseconds
☐	D	225 milliseconds

Edexcel GCSE Biology: Combined Science

Topic Questions

2.4 Co-ordination & Response