SL respiration 2

What piece of equipment can be used to measure the rate of respiration of an invertebrate or germinating seeds?

What is the function of the syringe in the setup?

• Reset the coloured liquid

• Prevent mixing of CO₂ and O₂

• Maintain air pressure

• Readings can be taken from it

Why is yeast used in the production of bread?

• Anaerobic respiration of yeast produces CO₂ which causes bread to rise

• Anaerobic respiration of yeast produces ethanol which causes bread to rise

• Aerobic respiration of yeast produces CO₂ which causes bread to rise

• Aerobic respiration of yeast produces ethanol which causes bread to rise

What is the function of the soda lime (or potassium hydroxide) in the setup shown?

• To release O₂

• To absorb O₂

• To release CO₂

• To absorb CO₂

Which anaeorbic product allows the production of champagne?

I - lactic acid

II - ethanol

III - carbon dioxide

• I and II only

• I and III only

• II and III only

• II only

Answer explanation

For regular wines the carbon dioxide is allowed to be released but the ethanol remains.

What is the purpose of the cotton wool?

• to stop the maggots touching the soda lime
• to keep the oxygen in the space above the maggots
• to insulate the maggots from the cold
• to keep the boiling tube bright

Why is the tube to the right in the boiling tube sealed?

• To allow gases to enter and exit the respirometer
• To stop gases entering and exiting the respirometer
• To keep the maggots warm
• There is no reason to seal that tube

What do you expect to see happen?

• The liquid in the manometer will move UP the ruler

• The liquid in the manometer will move DOWN the ruler

• The liquid in the manometer will NOT move

• The liquid in the manometer will move UP and DOWN the ruler

Answer explanation

Pressure of gas in the test-tube will decrease as oxygen is removed for respiration but volume of tube remains the same. Negative pressure draws the liquid up.

What is the rate of oxygen consumption in germinating corn at 12°C?

• 0.08 ml/min

• 0.04 ml/min

• 0.8 ml/min

• 1.00 ml/min

Answer explanation

Read off the value for 10 mins (0.4ml) and divide by 10 mins to get the volume per one minute = 0.4/10 = 0.04 ml/min

Which of the following conclusions is supported by the data?

• The rate of respiration is higher in non-germinating seeds than in germinating seeds.

• Non-germinating peas are not alive, and show no difference in rate of respiration at different temperatures.

• The rate of respiration in the germinating seeds would have been higher if the experiment were conducted in sunlight.

• The rate of respiration increases as the temperature increases in both germinating and non-germinating seeds.

• The amount of oxygen consumed could be increased if pea seeds were substituted for corn seeds.