Practicals

Question 1

cpac 1 -daphnia

Give two reasons why daphnia are used to investigate heart rate?

Answer 1

1. They are transparent so it is easy to see their heart beating
2. They have a less complex nervous system so they will not feel any pain
3. note- daphnia reproduce asexually so will not affect population of daphnia

Question 2

cpac 1 - daphnia

state the control used in Daphnia CPAC

Answer 2

• solution that does not contain caffeine
• to determine resting HR of daphnia

Question 3

c1

how do you analyse results for daphnia cpac

Answer 3

calculate mean hr of daphnia for each concentration and standard deviation - if no overlap in error bars then result is significant

Question 4

What is a control

Answer 4

Control is used for comparison to ensure valid results

Question 5

state the control variables in daphnia and many other experiments

Answer 5

Usually two from:
* age/size/species of daphnia
* temperature/ph/ acclimatisation time

Question 6

c17 - investigating breathing

Describe how to measure vital capacity

Answer 6

• difference between peak and trough in one cycle

Question 7

equation for respiratory minute ventilation

Answer 7

tidal volume x rate of breathing

Question 8

why is soda lime used for in cpac 17

Answer 8

**to absorb co2 **in order to ensure only volume of oxygen is measured

Question 9

what does spirometer measure?

Answer 9

change in volume of gases in breathing

Question 10

how can oxygen consumption per minute be measured using a spirometer trace

Answer 10

• difference in volume of one peak or trough compared to subsequent peak
• divide by time between two peaks or troughs and multiply by 60

Question 11

why is it important that co2 is removed from system in cpac 17

Answer 11

so changes in volume are only due to oxygen being used up