1. Energy Flow

2. Photosynthesis
Photosynthesis is the process in the green leaves
of multicellular plants in which light energy from
the Sun is converted to chemical energy stored in
sugar molecules. Organisms which carry out
photosynthesis are called producers.
6CO2 + 6H20 sunlight C6H1206 + 6O2
chlorophyll

5. Limiting Factors
The rate of photosynthesis is influenced by
Light intensity
CO2 concentration
Temperature
Colour of light

7. Heterotrophs
All organisms require organic molecules:
carbohydrates, lipids, proteins and nucleic acids to
survive.
Heterotrophs need to eat/ ingest other organisms
to obtain their supply of organic molecules
There are three groups
- Predators: eat other organisms
- Decomposers (Bacteria and fungi): absorb soluble
products
- Parasites: live in or on other organisms

8. What’s missing?

11. The food requirements of an organism will
depend on
Size
Activity level
Climatic factors
In general smaller animals will require more
food per unit of body mass than larger animals
10% of food eaten becomes part of the
organism. The majority is used for respiration to
produce energy, particularly heat to maintain
body temperature.

12. Energy
Energy cannot be created or destroyed only
transformed from one form to another.
In most cases, glucose reacts with oxygen in the
process of aerobic respiration producing waste
products, water and carbon dioxide.
C6H12O6 + 6O2 6H20 + Energy +6CO2

14. Aerobic Respiration
Aerobic respiration occurs in a series of steps or
a metabolic pathway, initially in the cytoplasm
(glycolysis) and the rest in the mitochondria.
Several of the steps in the metabolic pathway
release small quantities of energy to form ATP
A maximum of 38 ATP molecules are formed for
every molecule of glucose.

16. Anaerobic Respiration
When oxygen is not available, glucose is partly
broken down and the molecules produced are
much larger producing less energy.
Known as fermentation there are two types
1. Alcohol fermentation
2. Lactic Acid fermentation

18. Alcohol fermentation
Occurs in plants, yeast and bacteria. Glucose is
broken down to ethanol and carbon dioxide.
C6H12O6 C2H5OH + CO2 + Energy
Glucose ethanol + carbon dioxide +energy
Ethanol is a poison but can be used for brewing
and baking if a suitable conditions are maintained

19. Lactic Acid fermentation
Occurs in animals. Again inefficient and occurs in
the absence of oxygen.
C6H12O6 C3H6O3 + Energy
Glucose lactic acid +energy
No CO2 is produced but lactic acid will
accumulate. Lactic acid will convert to lactate,
dissolves in blood and is carried to the liver where
it will be converted pyruvate

22. Aerobic respiration of 1 molecule of glucose is a
more complete breakdown and as such releases
more energy to be transferred to synthesize ATP
molecules (36-38 ATP)
Fermentation of 1 molecule of glucose is a less
complete breakdown and as such less energy is
available to be transferred to ATP ( 2 ATP)

25. Energy Requirements
There are four particular areas that require
energy in the life of organisms
1. Growth
2. Movement
3. Repair
4. Reproduction