Practical 16
Investigating the rate of respiration
To measure the rate of aerobic respiration
Hypothesis
As the organism respires and the volume of oxygen in the tube decreases,the liquid will move down
the pressure gradient towards the respirometer
Respirometers measure the uptake of oxygen of the respiring mung beans by measuring the change
in gas volume surrounding the organic material. This makes it vital that all changes can be assumed
to be a result of oxygen changes; soda lime is used to absorb all carbon dioxide produced to ensure
this can be assumed.
Equipment
● Permanent marker
● Timer
● 5g mung beans
● Manometer containing coloured fluid
● 1cm3 syringe
● Wire mesh
● Soda lime
●
Variables
● Independent- temperature of the room
● Dependent- distance coloured liquid moved
● Control- same amount of mung beans
Risk assessment
➔ Probability/severity of risk:1-Low,2-Medium,3-High/Likely
➔ Total Risk: 1, 2,3, 4, 6, 9
Risk: Hazard: Probability: Severity: Total Risk: Precaution:
Broken Injuries from 1 2 2 Take care when
glass glass shards handling glass; Keep
away from edges
Soda lime Corrosive 1 2 2 Wear goggles to
avoid contact with
eyes; Avoid contact
with skin
Biohazard Contamination 1 1 1 Wear eye protection
and gloves; Wash
hands with soap
after handling
organisms
Method
1. Place soda lime in a boiling tube with a wire mesh on top of it and place a bung connected to
a manometer with coloured fluid inside in the tube
2. Place 5g of mung beans into the boiling tube and replace the bung into the test tube
3. Open the three way tap in the bung containing the mung beans and place a syringe in the tap.
Use the syringe to add oxygen to move the fluid so it is even either side of the tube
4. Mark the starting point of the fluid on the manometer using a permanent marker
5. Isolate the respirometer by closing the connection to the syringe and the atmosphere and
opening the connection on the second test tube
6. Start the stopwatch and measure the distance the liquid shifts in 5 minutes
Investigating the rate of respiration
To measure the rate of aerobic respiration
Hypothesis
As the organism respires and the volume of oxygen in the tube decreases,the liquid will move down
the pressure gradient towards the respirometer
Respirometers measure the uptake of oxygen of the respiring mung beans by measuring the change
in gas volume surrounding the organic material. This makes it vital that all changes can be assumed
to be a result of oxygen changes; soda lime is used to absorb all carbon dioxide produced to ensure
this can be assumed.
Equipment
● Permanent marker
● Timer
● 5g mung beans
● Manometer containing coloured fluid
● 1cm3 syringe
● Wire mesh
● Soda lime
●
Variables
● Independent- temperature of the room
● Dependent- distance coloured liquid moved
● Control- same amount of mung beans
Risk assessment
➔ Probability/severity of risk:1-Low,2-Medium,3-High/Likely
➔ Total Risk: 1, 2,3, 4, 6, 9
Risk: Hazard: Probability: Severity: Total Risk: Precaution:
Broken Injuries from 1 2 2 Take care when
glass glass shards handling glass; Keep
away from edges
Soda lime Corrosive 1 2 2 Wear goggles to
avoid contact with
eyes; Avoid contact
with skin
Biohazard Contamination 1 1 1 Wear eye protection
and gloves; Wash
hands with soap
after handling
organisms
Method
1. Place soda lime in a boiling tube with a wire mesh on top of it and place a bung connected to
a manometer with coloured fluid inside in the tube
2. Place 5g of mung beans into the boiling tube and replace the bung into the test tube
3. Open the three way tap in the bung containing the mung beans and place a syringe in the tap.
Use the syringe to add oxygen to move the fluid so it is even either side of the tube
4. Mark the starting point of the fluid on the manometer using a permanent marker
5. Isolate the respirometer by closing the connection to the syringe and the atmosphere and
opening the connection on the second test tube
6. Start the stopwatch and measure the distance the liquid shifts in 5 minutes
