Photosynthesis Flashcards
Give two examples of photosynthetic organisms
Green plants and algae
Where does the energy for photosynthesis come from?
The sun
What product is made in photosythesis?
Glucose
In which organelle does photosynthesis occur?
Chloroplasts
What do chloroplasts contain which absorbs light?
Chlorophyll
What is the word equation for photosynthesis?
light
carbon dioxide + water ———–> glucose + oxygen
chlorophyll
What is the symbol equation for photosynthesis?
6CO2 + 6H2O ————> C6H12O6 + 6O2
What kind of reaction is photosynthesis?
Endothermic
What is an endothermic reaction?
A reaction in which energy is taken in.
What 3 factors is photosynthesis affected by?
Light intensity, concentration of CO2 and the temperature.
What is a limiting factor in photosynthesis?
It is a factor that prevents photosynthesis happening any faster?
Why does temperature affect the rate of photosynthesis?
It affects the enzymes involved?
Do the enzymes required for photosynthesis work more quickly or more slowly at lower temperatures?
More slowly
What happens to the enzymes required for photosynthesis if it gets too hot?
They will become denatured.
At what temperature do the enzymes required for photosynthesis denature on average?
45 degrees C.
What does not enough light do to the rate of photosynthesis?
It lowers it.
What happens at first as you increase the light level?
The rate of photosynthesis increases steadily.
What happens after a certain point of increasing the light intensity?
The light intensity will stop making any difference. It’ll be either the temperature or the CO2 which is the limiting factor.
In the lab, what can you do to investigate the effects of light intensity on photosynthesis?
You can move a lamp closer to or further away from your plant.
What do you need to do if you want to plot your results against light intensity when using the method of moving a lamp further and further away from the plant.
Either use a light meter or use the inverse square law
Write the inverse square law
1
light intensity ∝ ——————————-
distance(d) squared
What is the inverse square law?
The square of the distance from the light source and the light intensity are inversely proportional to each other - this means as the distance increases, the light intensity decreases. However, light intensity decreases in proportion to the square of the distance.
What will happen to the light intensity if you double the distance?
It will be four times smaller
What will happen to the light intensity if you halve the distance?
It will be four times larger
What result does too little carbon dioxide have on photosynthesis?
It slows photosynthesis down.
What happens after a certain point on the graph of the rate of photosynthesis plotted against the level of CO2.
It flattens out.
