4.4 Photosynthesis Flashcards
Explain the shape of the graph at point A.
The rate of photosynthesis is increasing as temperature increases.
Becauses enzymes and substrates have more kinetic energy.
So there are more successful collisions.
What is the main limiting factor of photosnthesis during winter.
Temperature
What is the equation for photosynthesis?
Explain the shape of the line at point B on the graph:
Photosynthesis is happening at its optimum rate.
Becauses enzymes and substrates have maximum kinetic energy.
So there are maximum possible successful collisions.
DESCRIBE the graph below:
As temperature increases, rate of photosynthesis increases.
A maximum rate is reached.
Then the rate ogf photosynthesis decreases rapidly past the optimum temperature and stops at 45°C
Remember: you must include numbers from axis if they are given!!
How do plants make Amino acids?
They combine glucose with nitrates.
When using a lamp to look at how light intensity affects rate of photosynthesis, how can we increase the light intensity?
Move the lamp closer.
What is the symbol for magnesium ions?
Mg2+
Identify the limiting factor/s at point B
Explain how you know.
CO2 conc/Temperature/Chlorophyll/Water
Because when light intensity increases past this point rate of photosynthesis does not - so must be one of the other factors.
Identify the limiting factor at point A.
Explain how you know.
CO2 concentration.
because as CO2 concentration increases so does the rate of photosynthesis
What is the symbol for nitrates?
NO3-
What is meant by a limiting factor of photosynthesis?
Something that slows down the amount of photosynthesis that a plant can do.
Which type of energy allows carbon dioxide and water to be converted into glucose and oxygen?
Light energy
DESCRIBE the graph below…
As light intensity is increases rate of photosynthesis increases.
Eventually, the rate of photosynthesis remains constant.
Remember: if numbers are on the axis’ you mst include them in your description!!
Where do plants get nitrates?
From the soil
Why do plants need magnesium ions from soil?
to make chlorophyll
What is the symbol equation for photosynthesis?
Identify the limiting factor at point A.
Explain how you know.
Amount of light
because as light intensity increases so does the rate of photosynthesis
Identify the limiting factor/s at point B.
Explain how you know.
Light Intensity/Temperature/Chlorophyll/Water
Because when CO2 concentration increases past this point rate of photosynthesis does not - so must be one of the other factors.
What is the main limiting factor of photosynthesis on a Summer day? Explain your answer.
CO2 concentration.
Because it is generally warmer in Summer.
Because there is a higher light intensity in Summer.
Atmospheric CO2 is low (0.03%).
Explain the shape of the graph at point C.
The rate of photosnthesis is decreasing rapidy past the optimum temperature.
Because enzymes are denaturing.
Change to shape of active site.
Fewer successful collisions.
What 5 things do plants use glucose for?
- Oils - energy store
- Starch - energy store
- Cellulose - for cell walls
- Amino acids - for growth and repair
- Respiration - for energy
OSCAR (wil help you remember!)
DESCRIBE the graph below:
As CO2 concentration is increases rate of photosynthesis increases.
Eventually, the rate of photosynthesis remains constant.
Remember: if numbers are on the axis’ you mst include them in your description!!
A plant tha is lacking magnesium will show what symptoms?
Yellow leaves as less chlorophyll.
Poor growth as less photosynthesis happening.
What is the main limiting factor of photosynthesis at night time?
The amount of light
Starch is insoluble in the cytoplasm of plant cells. Why is this a useful property?
It does not increase the concentration of cytoplasm.
So water does not move into the cell via osmosis which would cause the cell to swell up.
What are the limiting factors of photosynthesis?
- Light
- CO2 concentration.
- Temperature
- Amount of chlorophyll
- Water availability
As you move a plant away from a lamp, the light intensity reaching the plant decreases. We say that distance and light intensity are i__________ p_____________.
inversely proportional
How can we calculate the light intensity coming from a lamp that is reaching a plant?
The Inverse Square Law
Light intensity = 1 ÷ Distance of plant from lamp²
How do farmers optimise conditions for photosynthesis?
The grow crops in a greenhouse.
How do greenhouses optimise photosynthesis?
- Artificial lighting allows photosynthesis to occur at night.
- Shades - can be shut if it gets too warm.
- Propane burner - releases CO2
- Maintain optimum temp for photosnyhtesis.
- Glass allows light to reach crops.
- Fertilisers can be used to supply minerals e.g. magnesium
A lamp is 30cm from some pond weed. What is the light intensity?
Light intensity = 1 ÷ Distance of plant from lamp²
1/30² = 0.001
A lamp is 10cm away from some pond weed. What is the light intensity?
Light intensity = 1 ÷ Distance of plant from lamp²
1/10² = 0.01
A lamp is 20cm away from some pond weed. What is the light intensity?
Light intensity = 1 ÷ Distance of plant from lamp²
1/20² = 0.0025
The light intensity of a lamp is 0.0001. How far from the pond weed is the lamp?
Light intensity = 1 ÷ Distance of plant from lamp² is rearranged to:
Distance of plant from lamp = √(1/light intensity)
Therefore:
√(1/0.0001) = 100 cm away
