Author: Carmen Nunez

1

Scientists investigated the effect of a 6-week exercise programme on the resting heart rate of males and females.

The scientists recruited a large group of male volunteers and a large group of female volunteers. They measured the resting heart rate of each volunteer before the exercise programme. Both groups took part in the same exercise programme. The scientists measured the resting heart rate of each volunteer after the exercise programme.

The scientists determined the mean resting heart rate and the range of resting heart rates for each group before and after the exercise programme. The graph shows their results.

(a)	What was the range of the resting heart rates in males after the exercise programme?

........................................................................................................................

(1)

(b)	Calculate the percentage decrease in the mean resting heart rate of females after the exercise programme. Show your working.

Answer = ............................ %

2

Large insects contract muscles associated with the abdomen to force air in and out of the spiracles. This is known as ‘abdominal pumping’. The table shows the mean rate of abdominal pumping of an insect before and during flight.

Stage of flight

Mean rate of abdominal pumping
/ dm ^3 of air kg ^−1 hour ^−1

Before | 42
During | 186

(a)	Calculate the percentage increase in the rate of abdominal pumping before and during flight. Show your working.

Answer ..................................... %

(2)

3

The following figure shows the scientists’ results.

(a)	Calculate the difference in the percentage of haemolysed cells between sheep and rabbit at a sodium chloride concentration of 0.5%.

..................................................

(1)

4

Table 1

Trial | Animal organ | Mean amount of oxygen used, in the absence or presence of cyanide, per hour / arbitrary units
| | No cyanide | 10^−4 mol dm^−3 cyanide | 10^−2 mol dm^−3 cyanide
A | Sheep liver | 2.7 | 2.5 | 0.7
B | Sheep kidney | 14.1 | 9.9 | 1.9
C | Ox liver | 1.9 | 1.5 | 0.8
D | Rat kidney | 20.7 | 18.8 | 2.3
E | Rat liver | 10.5 | 10.0 | 1.9
F | Guinea pig kidney | 16.8 | 14.4 | 1.9

(i)	Calculate the percentage difference in oxygen use for ‘rat liver’ ( Trial E) between a cyanide concentration of 10^−4 and 10^−2 mol dm^−3.

Percentage difference = ................................................................

(2)

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