Plant Biology Flashcards
What is photosynthesis?
When single celled organisms convert light energy into chemical energy.
What is the word equation for photosynthesis?
carbon dioxide + water -> glucose + oxygen
What is the symbol equation for photosyntheses?
6CO2 + 6H2O -> C6H12O6 + 6O2
What is a leaf?
The organ of the plant that carries out photosynthesis.
What do leaf cells contain?
Chloroplasts. Chloroplasts contain chlorophyll which absorbs light energy.
How are leaves adapted for their function?
- large surface area to absorb light
- thin, short diffusion distance
- veins, support the leaf and transport water into the leaf
- waxy surface stops leaves losing water
What is the structure of the leaf?
wax cuticle upper epidermis palisade layer spongy layer lower epidermis stoma / guard cells
How do you test a leaf for starch?
- leaf in boiling water for 3 mins
- place leaf in ethanol then in hot water bath
- leave until ethanol stops bubbling
- put leaf in hot water
- add iodine
What is a destarched leaf?
A plant that has been kept in a dark cupboard, it has no light therefore it cannot photosynthesise.
What would the results of a starch test on a destarched plant be?
There is no starch present so the iodine will stay orange brown.
What factors affect photosynthesis?
- temperature
- light intensity
- CO2 concentration
What are leaves designed to do?
Absorb light and take in CO2. They contain veins that bring in the water taken up by the roots.
What is the rate of photosynthesis?
How fast a plant carries out photosynthesis
Explain why greenhouse owners burn paraffin in their greenhouses
This makes heat and carbon dioxide, which could be limiting factors. If there is more carbon dioxide and its warmer they hope that photosynthesis will be faster. They will be wasting their money if light is the limiting factor as they could also use an artificial light.
Describe the practical that proves shows if carbon dioxide is necessary for photosynthesis
- get a destarched plant
- put the destarched plant in a bell jar with soda lime to remove the carbon dioxide from the air.
- leave for 24 hours in a light place.
- test leaves for starch with iodine
If CO2 is needed the leaves will not go blue/black
What are nitrate ions used for?
making proteins and amino acids
Where are nitrate ions obtained from?
soil through root hairs
What is water used for?
photosynthesis
Where is water obtained from?
soil through root hairs
What are magnesium ions used for?
making chlorophyll