Topic 9 - Plant nutrition and transport Flashcards
What is the definition of photosynthesis?
Chemical reaction that absorbs light energy and converts it to chemical energy in the form of glucose/starch in the presence of light and chlorophyll.
What is the word equation for photosynthesis?
Carbon dioxide + Water –> Glucose + Oxygen
What is the chemical equation for photosythesis?
6CO2 + 6H2O –> C6H12O6 + 6O2
What are the 3 things that affect the rate of photosynthesis? (3)
- Varying the carbon dioxide concentration
- Light intensity
- Temperature
Why do plants require mineral ions?
For growth
Why do plants require magnesium ions?
For chlorophyll
Why do plants require nitrate ions?
For amino acid
What does a lack of magnesium do to a plant?
A lack of magnesium ions leads to chlorosis as their isn’t enough magnesium required to make chlorophyll so this causes a leaf to turn lighter
What does a lack of nitrate do to a plant?
A lack of nitrate ions causes stunted growth of the leaf and discolouration
Describe the test for starch in a leaf? (9)
(1) Half fill a 250 cm3 beaker with warm water and place it on a tripod over a Bunsen burner. Heat the water till it boils and then turn down the Bunsen flame sufficiently to keep the water at boiling point.
(2) Place the leaf (from a destarched plant) into the boiling water for at least 5 minute. This will kill the cells, stop all chemical reactions and make the leaf permeable to alcohol and iodine solution later on.
(3) TURN OFF THE BUNSEN BURNER
(4) With the forceps, push the leaf carefully to the bottom of a test-tube and cover it with ethanol.
(5) Place the test-tube in the hot water and leave it for 5 minutes. The alcohol will boil and dissolve out the chlorophyll in the leaf.
(6) Use a test-tube holder to remove the test-tube from the water bath and tip the green alcoholic solution into the beaker for waste alcohol but take care not to tip the leaf out as well. Your leaf should be white or very pale green.
(7) Fill the test-tube with cold water and the leaf will should float to the top.
(8) Use forceps to spread the leaf flat in a petri dish. Use a dropping pipette cover the leaf with iodine solution for one minute.
(9) Take the leaf to the sink and holding it on the petri dish, wash away the iodine solution with some cold water.
How is the waxy cuticle adapted for photosynthesis?
A protective layer that allows light to enter the leaf. It is waterproof in order to prevent water loss by evaporation.
How is the Epidermis adapted for photosynthesis?
transparent, physical defence layer that does not contain chloroplasts. It allows light into the leaf.
How is the Palisade mesophyll layer adapted for photosynthesis?
Regularly shaped allowing many to pack together closely at the top of the leaf. These cells also have many chloroplasts in order to trap as much light as possible.
What is the Palisade mesophyll layer?
Plant tissue containing closely packed cells in the upper layer of a leaf.
How is the spongy mesophyll layer adapted for photosynthesis?
have very few chloroplasts and a large surface area to increase the diffusion of carbon dioxide and oxygen.