A-Level AQA Biology Nervous Coordination: Figure 4 shows a diagram of a Pa

Question

Figure 4 shows a diagram of a Pacinian corpuscle.

Figure 4

Name the structures labelled P, Q and R shown in Figure 4.

P
Q
R

Two students (A and B) investigated reaction time in response to touch.

- Student A sat with her eyes shut and her forearm resting on a wood block so that her hand was over the edge.
- Student B held a ruler vertically between student A's thumb and first finger, with the ruler at 0 mm lightly touching student A's first finger.
- Student B released the ruler.
- As soon as student A felt the ruler fall, she closed her thumb and first finger to catch the ruler as shown in Figure 5.
- Student B measured the distance the ruler had fallen to the nearest mm.

The test was repeated three more times using the same hand to catch the ruler. Table 3 shows student A's results.

Table 3

| Trial | Distance the ruler has fallen / mm |
|-------|----------------------------------|
| 1     | 79                               |
| 2     | 94                               |
| 3     | 10                               |

The student was able to convert these distances into reaction times using Table 4.

Table 4

| Distance the ruler fell / mm | Reaction time / ms |
|------------------------------|-------------------|
| 10                           | 45                |
| 20                           | 64                |
| 30                           | 78                |
| 40                           | 90                |
| 50                           | 100               |
| 60                           | 111               |
| 70                           | 120               |
| 80                           | 128               |
| 90                           | 136               |

02.2 Calculate the percentage uncertainty in the measurement of Trial 1 in Table 3.

Put a tick (✓) in the correct box below.

1. 0.633%
2. 1.27%
3. 2.53%
4. 12.6%

03. In this investigation, it is not possible for a student to react in less than 45 ms.

Suggest one explanation for the value recorded in Trial 3.

04. Student A estimated that the length of the nerve pathway involved was 175 cm.

Use Table 3 and Table 4 to calculate the mean speed of nerve impulse transmission.

Do not use the value for Trial 3 in your calculation.

Answer m s⁻¹

05. In response to touch, nerve impulses can be transmitted at speeds of 76.2 m s⁻¹.

Suggest three reasons why, in this investigation, the estimated speed of student A’s impulse transmission was less than 76.2 m s⁻¹.

1
2
3

Figure 4 shows a diagram of a Pacinian corpuscle - AQA - A-Level Biology - Question 2 - 2022 - Paper 3

Worked Solution & Example Answer:Figure 4 shows a diagram of a Pacinian corpuscle - AQA - A-Level Biology - Question 2 - 2022 - Paper 3

Name the structures labelled P, Q and R shown in Figure 4.

Calculate the percentage uncertainty in the measurement of Trial 1 in Table 3.

Suggest one explanation for the value recorded in Trial 3.

Use Table 3 and Table 4 to calculate the mean speed of nerve impulse transmission.

Suggest three reasons why, in this investigation, the estimated speed of student A’s impulse transmission was less than 76.2 m s⁻¹.

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