BIOENERGETICS
hotosynthetic Reaction:
P
Photosynthesis is the process by which plants make glucose from sunlight. It is an
endothermic reaction in which energy is transferred from the environment to the
chloroplasts by light
6CO2 + 6H2O → C6H12O6 + 6O2
Rate of Photosynthesis:
● Temperature: the higher the temperature the faster the rate of the reaction
● Light intensity: the higher the light intensity, the faster the rate of the
reaction
● Carbon dioxide concentration: as the concentration of carbon dioxide
increases, the rate of reaction increases
● Amount of chlorophyll: Chlorophyll is the pigment in the leaf that converts
light energy to food for the plant. If there is a lack of it the rate of
photosynthesis will be severely reduced
Required Practical (effect of light intensity on photosynthesis):
3
1 . M easure 20𝑐𝑚 of sodium hydrogen carbonate into a boiling tube
2. Cut a 10 cm piece of pondweed and put a paperclip on one side
3. Place the pondweed in the boiling tube and shine a light onto the
pondweed
4. Position the boiling tube so that the pondweed is 10 cm away from the
light source. Allow the boiling tube to stand for two minutes. Count the
number of bubbles emerging from the cut end of the stems in one minute.
5. Repeat steps 1-4 moving the lamp 10 cm away each time for five distances
6. Do the entire experiment 3 times and record the average
heindependent variableis the light intensity
T
Thedependent variableis the amount of bubbles produced
Thecontrolled variableswere, the time, the amount of pondweed, the lightused
etc.
Uses of Glucose from Photosynthesis:
● or respiration
F
● Converted into insoluble starch for storage (in roots, stems and leaves)
● To produce fat or oil for storage (in seeds)
● To produce cellulose to strengthen cell walls
hotosynthetic Reaction:
P
Photosynthesis is the process by which plants make glucose from sunlight. It is an
endothermic reaction in which energy is transferred from the environment to the
chloroplasts by light
6CO2 + 6H2O → C6H12O6 + 6O2
Rate of Photosynthesis:
● Temperature: the higher the temperature the faster the rate of the reaction
● Light intensity: the higher the light intensity, the faster the rate of the
reaction
● Carbon dioxide concentration: as the concentration of carbon dioxide
increases, the rate of reaction increases
● Amount of chlorophyll: Chlorophyll is the pigment in the leaf that converts
light energy to food for the plant. If there is a lack of it the rate of
photosynthesis will be severely reduced
Required Practical (effect of light intensity on photosynthesis):
3
1 . M easure 20𝑐𝑚 of sodium hydrogen carbonate into a boiling tube
2. Cut a 10 cm piece of pondweed and put a paperclip on one side
3. Place the pondweed in the boiling tube and shine a light onto the
pondweed
4. Position the boiling tube so that the pondweed is 10 cm away from the
light source. Allow the boiling tube to stand for two minutes. Count the
number of bubbles emerging from the cut end of the stems in one minute.
5. Repeat steps 1-4 moving the lamp 10 cm away each time for five distances
6. Do the entire experiment 3 times and record the average
heindependent variableis the light intensity
T
Thedependent variableis the amount of bubbles produced
Thecontrolled variableswere, the time, the amount of pondweed, the lightused
etc.
Uses of Glucose from Photosynthesis:
● or respiration
F
● Converted into insoluble starch for storage (in roots, stems and leaves)
● To produce fat or oil for storage (in seeds)
● To produce cellulose to strengthen cell walls
