Photosynthesis and plants Flashcards
What is photosynthesis?
In photosynthesis plants, make food (sugars and starch) using light energy. The light is trapped by chlorophyll, in chloroplast, in plant leaves
What is the word equation for photosynthesis?
Light
Carbon dioxide + water ———> glucose + oxygen
Chlorophyll
What is the chemical equation for photosynthesis?
6CO2 + 6H2O - - - -> C6H12O6 + 6O*2
What kind of reaction is photosynthesis?
Endothermic
What is the test for starch in leaves?
The starch, the plant by leaving it in complete darkness for 48 hours
Dip leaf in boiling water that has been heated by a Bunsen burner for 30 seconds
Turn off Bunsen burner and put leaf in the test tube of ethanol and stand the test tube on a beaker of hot water for 10 minutes
The leaf and hot water
Spread the leaf, fight flat on a petri dish and cover it with iodine solution
If the adding goes from yellow – brown to blue – black, starch is present
Why do we dip the leaf in ethanol during the test for starch?
The chlorophyll is removed to make it easier to see the colour change with iodine
How do you show that light is needed for photosynthesis?
De starch plant
Partially cover leaf with foil
Put leaf in bright light for six hours
Test Leaf for starch
Result: starch is only produced in areas that receive light
How do you show the chlorophyll is needed for photosynthesis?
De starch variegated leaf ( part green part white leaf)
Put plant in bright light for six hours
Test for starch
Results: starch is only on green parts of leaf
How do you show that carbon dioxide is needed for photosynthesis?
DeStarch plant
Cover the plant with a clear plastic bag and put sodium hydroxide solution beside the plant , this absorbs the carbon dioxide from the air inside the plastic bag
Leave the plant in bright light for six hours
Starts test
Result: negative starch test will show carbon dioxide is necessary for photosynthesis
How do you show the oxygen is produced in photosynthesis?
The rate of photosynthesis affects the rear of which bubbles of oxygen are given off. This can be used to compare photosynthesis rates in different conditions. For example by moving a lump position it is possible to see the effect of light intensity on photosynthesis.
How is temperature, a limiting factor in photosynthesis
The rate of photosynthesis increases steadily with arise in temperature up to a certain point. After this enzymes are destroyed (denatured) and reaction stops completely.
How is carbon dioxide limiting factor in photosynthesis?
If there is two little, the rate will slow down, carbon dioxide may be limited in an enclosed. Space.
Highest light a limiting factor in photosynthesis
A lack of light will slow the rate on as light provides energy
What are the three main sections of a leaf structure?
Epidermis – no chloroplasts
Palisade mesophyll - many chloroplasts
Spongy mesophyll - cells with air spaces and less chloroplasts
What plant adaptations help light absorption
Large surface area
Thin, transparent cuticle
Tightly packed cell, and under the upper surface with many chloroplast, rich and chlorophyll
