A-Level Edexcel Biology Linear Relationships

Review A-Level Edexcel Biology linear relationships through y=mx+c calculations, graph gradients, intercepts and biological predictions from straight-line data.

Exam points

use y=mx+c to calculate biological values such as heart rate from linear data
write straight-line equations from biological graphs using gradient and intercept

[Maximum number: 3]

Exercise affects the cardiac output of a person.
The graph shows the change in heart rate following exercise for an unfit person and for a fit person.

Figure for Question A.3.3—Linear relationships question 1 — Edexcel A-Level Biology A2

Calculate the heart rate of the unfit person at 5 minutes.

The change in heart rate of the unfit person is a linear relationship.
Use the equation for a straight line y=mx+c.

An answer showing the following steps:

- value of mx(1)

- value of y (1)

- correctly rounded to a whole number with units (1)

$(-65 \div 240) \times 300$
= -81.25
$=(-65 \div 240 \times 300)+190=108.75$
109 bpm
Accept range 107-111

(3)

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A.3.3—Linear relationships question 1