Photosynthesis F4 Flashcards
How is the epidermis adapted for light absorption?
Transparent and no chloroplast to allow light to pass through.
How is the waxy cuticle adapted for gas exchange/light absorption?
Prevents water loss and is thin transparent to let light pass through.
How is the palisade mesophyll adapted for light absorption?
Many chloroplasts and cells packed tightly end to end to ensure max. light absorption for P/S.
How is the spongy mesophyll adapted for gas exchange?
Fewer cells to facilitate diffusion of gases.
How are the intercellular spaces adapted for gas exchange?
Air spaces to facilitate diffusion of CO2 and O2.
How are the guard cells adapted for gas exchange?
Regulate opening and closing of stomata.
What is an endothermic reaction?
one which takes in energy from the surroundings
What is the process of photosynthesis?
light is taken in and reaction occurs in the chloroplasts
What is the process of respiration?
glucose is used to produce energy
What is the word equation for photosynthesis?
carbon dioxide + water —> glucose + oxygen
What is the balanced chemical equation for photosynthesis?
6CO2 + 6H2O —> C6H12O + 6O2
Why are plants destarched before the practical?
If the starch test at the end is +ve then it shows starch was produced during the experiment
Describe the procedure of the leaf starch test
- boil leaf in water (stops chemical reactions)
- boil leaf in ethanol (removes chlorophyll)
- place leaf back in water (softens leaf)
- add iodine (yellow/brown - blue/black)
Why is the leaf destarched for 48hrs?
To give enough time for the starch to be used up
Why is it necessary to also test an un-destarched leaf?
To check all starch has been broken down and compare results
Describe the procedure to test the need for light and chlorophyll in photosynthesis
- destarch plant for 48hrs
- test leaf from destarched plant for starch. if negative:
- cover a part of leaf with light proof paper
- place plant in bright light for several hours
- test for starch
What acts as a control in the test for the need of light and chlorophyll in photosynthesis?
The green part of the leaf
How do limiting factors affect photosynthesis?
They slow down and prevent maximum rate of photosynthesis
What are the limiting factors of photosynthesis?
- carbon dioxide
- temperature
- light
Describe and explain the affect of light intensity in photosynthesis
As light intensity increases, the R.O.P also increases up to a point where the graph levels off and forms a plateau. An increase in light intensity causes an increase in photosynthesis
How you increase the amount of carbon dioxide in water?
Blow into the water using a straw
How is Sodium Hydroxide used in the production of oxygen?
It absorbs CO2 to act as a control
How do you measure the R.O.P?
count the bubbles of oxygen in a set time period
How do you change the light intensity?
Move the LAMP at varying distances from the beaker
