1. Bioenergetics revision
Photosynthesis and respiratioin

2. Don’t forget that plants also carry out Respiration to make energy.
Photosynthesis
Water + Carbon Dioxide Glucose + Oxygen
Sunlight
chlorophyll
From roots/soil
From air through stoma
Stored as starch
Released into air
6 H2O CO C6H12O O2
Don’t forget that plants also carry out Respiration to make energy.
Chlorophyll
Green pigment
Found in chloroplasts
Absorbs light energy

3. Plant Tissues
Know the features of each layer and how they help photosynthesis

4. Factors Affecting Photosynthesis
As factor rises, so does the rate of photosynthesis
Temperature
- Above 45oC, enzymes denature
Carbon dioxide
Light intensity
Nutrients
Water
Space to grow
All of these, at a particular time, may be the limiting factor.
Temperature

5. Light Intensity
Without enough light, a plant cannot photosynthesise very quickly, even if there is plenty of water and carbon dioxide. Increasing the light intensity will boost the speed of photosynthesis.
Can you explain what is happening here?

6. CO2
Something other than CO2 concentration is acting as a limiting factor
Sometimes photosynthesis is limited by the concentration of carbon dioxide in the air. Even if there is plenty of light, a plant cannot photosynthesise if there is insufficient carbon dioxide.

7. Temperature
If it gets too cold, the rate of photosynthesis will decrease. Plants cannot photosynthesise if it gets too hot. Why?

8. Greenhouses and Poly-tunnels Controls the environment Light
Temperature
Nutrient levels
Water levels
Predators
Weeds
Reduces the chance of
Limiting factors
Hydroponics
Growing in plants in nutrient rich water, not soil.

9. Respiration
Site of respiration- mitochondria

10. Anaerobic Respiration produces less energy than Aerobic Respiration!
Takes place in all cells (apart from RBCs).
Carried out by the mitochondria.
Needed for energy to:
Build new molecules and cells
Movement- needed to make muscle cells contract
Keep birds and mammals (warm blooded) at a constant temperature
Glucose + Oxygen Carbon dioxide + Water
C6H12O O CO H2O
Anaerobic Respiration
Takes place where no oxygen is present.
Muscle cells
Yeast Cells
Anaerobic Respiration produces less energy than Aerobic Respiration!
Glucose Lactic Acid
Glucose Ethanol (alcohol)

11. Stored glucose found in muscles
The Effects of Exercise
Heart rate 
Breathing rate 
more Oxygen and Glucose supplied to muscles
Increase in Respiration rate
More Energy for muscle contraction.
Glycogen
Stored glucose found in muscles
Oxygen Debt
Amount of oxygen needed to breakdown Lactic acid, formed during anaerobic respiration.
Lactic acid + Oxygen Carbon dioxide + water

12. B2 REVISION – CHAPTER 2 – ORGANISMS IN THE ENVIRONMENT
What is the equation for photosynthesis
Where in the plant does it occur?
How are leaves adapted to perform photosynthesis?
Explain how plants use glucose for the following:
Respiration
Transport
Storage
How doe the follow factors affect organisms in their environment?
Temperature:
Light:
Water:
CO2 and O2:
Explain how light, CO2 and temperature are limiting factors of photosynthesis
How do we measure the distribution of organisms?
How do we know this data is accurate?
KEY WORDS:
Photosynthesis
Median
Glucose
Mode
Limiting factors
Transect
Quadrat
Reproducible
Sample size
Valid
Range
Variables
Mean
ASSESSMENT: