Topic 7 and 8

Question 1

Rate of respiration

Answer 1

Set up apparatus as shown
Add seeds to one and glass beads to another
Decrease in air volume due to oxygen consumption reduces pressure in tube causing the dye to move towards the test tube
CO2 is absorbed by KOH reducing pressure

Question 2

Habituation

Answer 2

Place one snail on a clean surface
Wait until snail has emerged from shell
Dampen cotton wool and touch snail between stalk
Start stop watch and time how long it takes to reemerge

Question 3

Spirometer

Answer 3

Oxygen filled chamber

Person breathes through tube and is recorded by pen on spirometer trace

Question 4

How do you work out tidal volume, breathing rate and oxygen consumption

Answer 4

BR - Count number of peaks in a minute
TV - difference in volume of gas for a peak
OC - Change in volume of gas (gradient) lowest point at beginning and end