Plant Nutrition Flashcards
What is photosynthesis
Photosynthesis is the process by which plants make carbohydrate as food.
How is the carbohydrate stored?
It is stored on the form of starch
What is starch?
Starch is a store of energy.
What kind if biological molecule is starch?
A carbohydrate
What is the physical form of starch?
Colourless grains
Where are the colourless grains of starch stored in the leaf?
In the cytoplasm, in the palisade and spongy mesophyll cells/layers
How do you test for starch?
Iodine test [with iodine solution]
What is the first step in testing for starch?
Boil a beaker of water then turn off the heat source
What is the second step when testing for starch?
The leaf is held in a pair of forceps and dipped in the hot water for abt 30 secs.
Why do you have to dip the leaf in hot water for 30 secs [starch test]
This kills the cells and prevents any further reactions taking place in them. Also makes it easier for the iodine solution to enter the cells.
What is the third step in testing for starch?
The is then placed in the bottom of a test tube and covered with ethanol.
What is the 4th step in testing for starch?
The test tube is placed in the beaker of hot water.
What happens after placing the test tube in the beaker of hot water?
Alcohol has a boiling that is below that of the how water and as it boils it dissolves most of the chlorophyll in the cells and makes starch grains easier to see when they are stained in iodine
What is the positive colour of a starch test?
Blue/black
What is the negative colour of a starch test?
Dark brown
What is the last step of the starch test?
The alcohol is the test tube is removed and the leaf is boiled again and is spread out on a white tile and iodine is dropped on the leaf
How is the condition leaf after it has been boiled [starch test]
It is brittle
What is a plant from which starch has been removed?
A destarched plant
How is a plant destarched?
By putting it in a dark place eg a cupboard
How many days does it take for a plant to be destarched?
2 or 3 days
Where is water drawn from in the plant?
The roots
What do you need to you test for Carbon dioxide in starch productiction
2 destarched plants with a dish of soda lime and sodium Hydrogencarbonate solution
What does soda lime do?
It absorbs carbon dioxide form the air.
What does sodium Hydrogencarbonate do?
It releases carbon dioxide onto the air.(enriches the air with CO²)
How does the carbon dioxide starch solution rest take place.
- Plants are set up in sunny place and left for few hours.
2.each leaf from the plant is test for starch - The leaf form the plant with soda lime which doesn’t contain carbon dioxide doesn’t contain starch.
- The leaf from the plant with sodium hydrogencarbonate solution containing CO² contains starch.
- This shows that carbon dioxide is needed for starch production.
What is the word equation of starch
Water + carbon dioxide –> carbohydrate(starch)