Respiration (T2) Flashcards
Explain the difference between aerobic and anaerobic respiration..
AEROBIC
- uses oxygen
- releases a lot of energy
- waste products are carbon dioxide and water
ANAEROBIC
- does not use oxygen
- releases a low amount of energy
- waste products are lactic acid (animals) and ethanol (plants)
How else can respiration be described?
Gaseous exchange
What are the waste products of aerobic respiration?
Carbon dioxide and water
What are the waste products of anaerobic respiration?
Lactic acid in animals, ethanol in plants
What happens to energy released by respiration that is not used?
It is stored for later by making a special energy rich molecule called Adenosine Triphosphate (ATP)
What is respiration in one sentence?
The break down of food molecules to release the stored chemical energy they contain.
Which cells of the human body does respiration take place in?
Every cell of the human body
What is the main food that is oxidised in respiration and why?
The main food oxidised is glucose. Glucose contains stored chemical energy that can be used for a variety of processes such as…
- contraction of muscles
- active transport of molecules
- building large molecules like proteins
- cell division
What is the word equation for aerobic respiration?
Glucose + oxygen -> carbon dioxide + water (+ energy)
What is the chemical equation for aerobic respiration?
C6H12O2 + 6O2 -> 6CO2 + 6H2O (+ energy)
Give an example of when the use of anaerobic respiration can be useful in yeast cells and give the word and chemical equations…
When yeast cells are prevented from getting enough oxygen, they start respiring anaerobically. The glucose is partly broken down into ethanol (alcohol) and carbon dioxide.
The ethanol is the alcohol in wine and beer, the carbon dioxide the gas that makes bead rise when baked…
Glucose -> ethanol + carbon dioxide (+ some energy)
C6H12O6 -> 2C2H5OH + 2CO2 (+ some energy)
Describe a situation in animal cells where anaerobic respiration can be useful. Give the word and chemical equations…
If muscle cells are overworked, the blood cannot reach them fast enough to deliver oxygen for aerobic respiration. The glucose if broken down into lactic acid.
If the muscles continue to be overworked, the lactic acid builds up in the bloodstream and muscle cramps occur. The person then needs to rest to fully oxidise the lactic acid.
The amount of oxygen needed to completely oxidise the lactic acid is known as the “oxygen debt”
Glucose -> lactic acid (+ some energy)
C6H12O6 -> 2C3H6O3
Describe an experiment to demonstrate the production of carbon dioxide by small living organisms…
Hydrogencarbonate solution is orange, but turns yellow if carbon dioxide is added.
1) place organisms on a gauze platform in a stoppered boiling tube, with hydrogencarbonate indicator solution in the bottom of the tube
2) measure the rate at which the indicator changes colour
Describe an experiment to demonstrate that heat is produced by respiration..
1) soak one set of peas in water for 24 hours so they begin to germinate
2) boil another batch of peas to kill them
3) wash both sets of peas in a 1% bleach solution, surface sterilising and killing any bacteria
4) rinse twice in distiller water to remove all bleach
5) put each batch of peas in inverted vacuum flasks, leaving some air in each flask
6) each flask is plugged with a thermometer and cotton wool - this allows the carbon dioxide gas that the seeds produce to escape
7) measure the temperature of the flasks
8) leave the flasks for a couple of days
9) measure the temperature again
