B8 Photosynthesis Flashcards
(42 cards)
Photosynthesis
Process when plants and some other organisms convert light energy into chemical energy in the form of glucose
Word equation for photosynthesis
light
Carbon dioxide + water —————–> glucose + oxygen
Symbol equation for photosynthesis
light
6CO2 + 6H2O —————–> C6H12O6 + 6O2
Describe process of photosynthesis
Photosynthesis uses energy to convert carbon dioxide and water into glucose and oxygen
Where does photosynthesis take place
In chloroplasts in green plant cells
How is energy transferred to the chloroplasts from the environment
By light
How plants get the materials they need for growth
From air and water
Describe how the leaf is adapted for photosynthesis
A leaf usually has a large surface area, so that it can absorb a lot of light
Contains palisade cell to absorb light
How adaptations of the leaf make photosynthesis efficient
Light provides energy needed for photosynthesis
As light level is raised rate of photosynthesis increases
Why do plants need light for photosynthesis
To convert carbon dioxide and water into carbohydrates
Describe an experiment to prove that plants carry out photosynthesis when exposed to light
Place boiling tube so pondweed is 10 cm away from light source
Allow boiling tube to stand for five minutes
Count number of bubbles emerging from the cut end of the stems in one minute
Repeat the count five times and record your results
Why chlorophyll is needed for photosynthesis
To absorb light
What is amount of chlorophyll in a plant be affected by
Disease or environmental stress such as lack of nutrients
These factors can damage chloroplasts or not make enough chlorophyll
Why would photosynthesis be reduced if there isn’t enough chlorophyll
They can’t absorb as much light
List the factors that affect the rate of photosynthesis
Temperature
Carbon dioxide concentration
Light intensity
Amount of chlorophyll
How does temperature affect the rate of photosynthesis
As temperature increases the number of collisions between enzymes and substrate increases, so rate of photosynthesis increases
What happens to enzymes at high temperatures
Denatured
How does carbon dioxide concentration affect the rate of photosynthesis
As CO2 increases the plant can use more of the available light and water to photosynthesis
If concentration of carbon dioxide is increased, the rate of photosynthesis will increase
How does light intensity affect the rate of photosynthesis
Increased light intensity means more energy is available to drive the light-dependent reactions
What is photoinhibition
If light intensity continues to increase beyond saturation point it can lead to photoinhibition where rate of photosynthesis decreases
Why low temperature limits rate of photosynthesis
If its too low the enzymes needed for photosynthesis work more slowly at low temperatures
Why shortage of carbon dioxide limits rate of photosynthesis
When there is a shortage of CO2 there isn’t enough carbon available to produce glucose
Why shortage of light intensity limits rate of photosynthesis
Without enough light, a plant cannot photosynthesise very quickly
how the rate of photosynthesis will be affected with more than one limiting factor
Any change in the level of a limiting factor will affect the rate of reaction
