1. Biology
Respiration

2. Learning Intentions 1. The main source of energy in cells is
from glucose found in our food
2. What type of energy is in glucose?
3. How do cells release energy from glucose?
4. Describe the stages involved in respiration

3. 1. Energy for cells Humans eat food for energy
Food contains chemical energy
Glucose (in food) is broken down by the process of respiration and its energy is stored in ATP
Aerobic Respiration happens in the mitochondria of cells
The chemical energy in ATP can be released by breaking it down.

4. 2. Aerobic Respiration Respiration is the process by which
chemical energy is released in cells
during the breakdown of food e.g.
glucose

5. 3 Aerobic Respiration Aerobic Respiration involves the presence of
oxygen and it occurs in 2 stages:-
1- Glycolysis
2- Breakdown of Pyruvic Acid

6. 3a) Glycolysis
Glycolysis produces 2 ATP

7. 3b) Breakdown of Pyruvic Acid
Pyruvic Acid + Oxygen
36ADP + 36Pi
36ATP
Carbon Dioxide + Water
This stage produces 36ATP
Total ATP produced in Aerobic Respiration is 38ATP

8. 4. Anaerobic Respiration
In anaerobic respiration, only glycolysis occurs, so only 2 ATP are made
In animals
Glucose Lactic Acid
In plants & fungi
Glucose Ethanol + Carbon Dioxide

9. 5. Comparing Aerobic & Anaerobic Respiration
Humans
Glucose + Oxygen￫Carbon Dioxide +Water
Glucose ￫ Lactic Acid
Plants & Fungi
Glucose ￫ Ethanol + Carbon Dioxide
ATP
38 ATP
2 ATP

10. 6. Measuring the Rate of Respiration

11. 7) Uses of Anaerobic Respiration
Humans use the process of Anaerobic Respiration to make useful products e.g. Bread, Beer, Wine,
The Anaerobic process that involves the chemical breakdown of a substance by microbes is also called Fermentation

12. 8) Fermentation & Baking Industries
yeast
Glucose Ethanol + Carbon Dioxide
Yeast is a single celled fungi that feeds on glucose.
Carbon dioxide makes the dough rise
The ethanol evaporates in the oven
Practical -Yeast & height of dough

13. 9) Fermentation & Brewing
yeast
Glucose Ethanol + Carbon Dioxide
The ingredients for Beer can be added to
large tanks called Fermenters.
Yeast change the glucose into ethanol by the process
of Fermentation. This is Anaerobic Respiration.
Computers control the temperature and pH to
provide the optimum conditions for the yeast
Practical – Yeast, grape juice & a balloon!

14. 10) Fermentation & Renewable Energy
Bio-renewables are types of renewable energy produced by living things.
Examples of Biorenewables are Biofuel, Biodiesel and Biogas
Biofuel (e.g. Ethanol)
Ethanol is made by fermenting the sugar in sugar cane, sugar beet, wheat, maize or wood pulp.
Biodiesel (e.g. Alcohol and Oils)
Biodiesel is produced by mixing alcohol with oils that have been extracted
from plants such as rape seed, soybean or from waste vegetable oils
Biogas (e.g. Methane)
Biogas is produced from decomposing animal or plant waste.
Practical – Producing Biodiesel

15. 11 Fermentation & Dairy Industries
YOGHURT MAKING
bacteria
Lactose Lactic Acid
Sugar
Bacteria feed on lactose sugar in milk
The milk clots and becomes acidic
making yoghurt
Yoghurt Practical
Wine, Yoghurt and cheese making video clip

16. 11 Fermentation & Dairy Industries
Bacterial Industries (Cheese)
bacteria
Lactose Lactic Acid
Sugar
Bacteria feed on lactose sugar in milk
The milk clots and becomes acidic making yoghurt
The enzyme Rennet is then added.
Rennet clots the protein in milk to make curds, and
the liquid part left is called the whey

17. 12. Fermentation Summary Brewing Baking Yoghurt Fungi (yeast) Bacteria
Type of microbe
Fungi
(yeast)
Bacteria
Word
Equation
yeast
Glucose Ethanol + Carbon Dioxide
bacteria
Lactose Lactic Acid
Sugar