MAKING SENSE OF
RESPIRATION
IGCSE Biology
1.1 Life Processes – Respiration
Brought to you by
MrExham.com
Image © Depositphotos.com/[julos #4371007]
• Can you remember how respiration releases energy?
• Can you write out the word equation, and the balanced
symbol equation, for aerobic respiration?
• Can you write out the word equation for anaerobic
respiration?
• What are the differences between aerobic and anaerobic
respiration?
• Can you describe simple experiments to show that carbon
dioxide and heat are produced by respiring seeds or other
suitable living organisms?
• A chemical reaction that happens in all our
cells to release energy.
• This can be used for
1. Contraction of muscle cells, producing
movement
2. Active transport of molecules and ions
3. Building large molecules, such as proteins
4. Cell division
• The reaction also releases some heat which is
used to maintain steady body temperature.
Word equation:
Chemical equation:
• Respiration using oxygen.
• Occurs in the mitochondria of a cell.
• Respiration without oxygen.
• We shall look at examples in two types of cell.
• Respiration without oxygen.
• Respiration without oxygen.
• Also known as
.
• Yeast cells are single celled fungi.
• Used for commercial purposes such as
brewing.
• Also known as
.
• Yeast cells are single celled fungi.
• Used for commercial purposes such as
brewing.
• Occurs when the blood cannot reach the
muscles fast enough to supply them with the
required oxygen.
http://www.flickr.com/photos/sumofmarc/7715537014/
• Occurs when the blood cannot reach the
muscles fast enough to supply them with the
required oxygen.
http://www.flickr.com/photos/sumofmarc/7715537014/
• Anaerobic respiration provides enough energy to
keep the muscles working for a short time.
• However lactic acid builds up in the blood which
causes cramps.
• The lactic acid has to be broken down using
oxygen.
• The volume of oxygen needed to completely
oxidise the lactic acid that builds up in the body
during anaerobic respiration is called
Aerobic
Anaerobic
Uses oxygen
No oxygen
Occurs in mitochondria of cell
Occurs in cytoplasm of cell
Releases lots of energy
Releases only a small amount of energy
Carbon dioxide and water is produced
Lactic acid or ethanol is produced
• This apparatus can be used to investigate how small
living organisms respire such as woodlice, maggots or
germinating seeds.
Living organisms
Gauze
Hydrogencarbonate indicator – This will change
colour from red to yellow when the carbon
dioxide level increases due to respiration.
The germinating seeds are respiring and therefore releasing heat. The boiled
seeds have been killed and are therefore not respiring anymore.
Cotton wool
Thermometer
Thermal flask