Plant structures and Their Functions Flashcards
(46 cards)
What happens during Photosynthesis?
Photosynthetic organisms, such as green plants and algae, use energy from the sun to make glucose.
Some of the glucose is used to make…
larger, complex molecules that the plants or algae need to grow. Make up the organisms biomass.
How are photosynthetic organisms the main producers of food?
The energy stored in the organisms biomass then works its way through the food chain as animals eat them and each other.
What is the equation of photosynthesis?
Carbon dioxide + Water -> Glucose + Oxygen
Uses light energy.
Is photosynthesis exothermic or endothermic?
Endothermic as energy is taken in during the reaction.
What 3 factors affect the rate of photosynthesis?
Light intensity, the concentration of CO2 and the temperature.
What is a limiting factor?
It stops photosynthesis from happening any faster
As light level is raised…
the rate of photosynthesis increases steadily. Only true up to a certain point.
Beyond the certain point the light intensity will not…
make any difference - it will either be the temperature or the CO2 level which is the limiting factor.
How can you investigate light intensity in a lab?
By moving a lamp closer to or further away from your plant.
If you just plot the rate of photosynthesis against “distance of lamp from the plant”…
you get a weird-shaped graph.
The distance from the lamp and light intensity are…
inversely proportional. This means as the distance increases, the light intensity decreases.
What is the inverse sqaure law?
light intensity is proportional to 1/(distance)^2
The inverse square law means that…
if you halve the distance, the light intensity will be four times greater.
Increasing the CO2 concentration increases…
the rate of photosynthesis up to a point.
If temperature is the limiting factor…
its because its too low.
The enzymes needed for photosynthesis work more slowly at…
low temperatures.
What happens if the plant gets too hot?
The enzymes it needs for photosynthesis and its other reactions will be denatured. This happens at about 45 degree celsius.
Why do plants have millions of microscopic root hairs?
It gives the plant a large surface area for absorbing water and mineral ions from the soil.
What are Phloem tubes made of?
Columns of elongated living cells with small pores in the end walls to allow stuff to flow through.
What do Phloem tubes transport?
Food substances made in the leaves to the rest of the plant for immediate use or for storage.
What is this process of transporting food substances called?
Translocation
What does Translocation require?
Energy from respiration.
In Phloem tubes, does the transport go in both directions?
Yes.