Topic 6- Plant Structures And Their Functions Flashcards
Photosynthesis word equation and then symbol equation
Carbon dioxide + water > glucose + oxygen
6CO2+ 6H2O > C6H12O6 + 6H2O
What type of reaction is photosynthesis
Endothermic
Bio mass
Mass of living material
Where do photosynthetic organisms get their energy from?
What do they store it as?
They get their energy from the sun to form glucose which is stored as starch (larger, complex molecule)
Photosynthetic organisms role in the food chain
Main producers of nearly all life on earth as animals eat it and then are eaten.
Where does photosynthesis take place?
In the chloroplasts
Containing chlorophyll which absorbs light and so energy
What affects the rate of photosynthesis
Water availability Carbon dioxide availability Light intensity Temperature Chlorophyll availability
How to test for starch
Boil a leave in water for 30 secs.
Then boil in ethanol for a few mins which is heated using a water bath
Dry with distilled water and place on white tile
Add iodine solution from a pipette which will detect starch after a few minutes by turning black.
What does boiling the leaf in water do?
Stop chemical reactions from occurring
What does boiling in ethanol do?
Decolorisation
Needs water bath as ethanol is flammable
How do you distract a plant
Leave in the dark for a few hours
How to investigate the effects of light intensity on rate of photosynthesis
- ) set up apparatus (including gas syringe, ruler, conical flask w water in and light source) and put sodium hydrogencarbonate into water.
- ) place light source at specific distance away from the plant
- ) leave to photosynthesise for a set time
- ) as it photosynthesises, released oxygen will collect in the gas syringe to accurately measure volume of gas produced
- ) repeat w different distances away from light
Why is sodium hydrogen-carbonate added to the water?
To provide it with CO2.
Is a control variable that can be controlled by set amount of sodium hydrogen-carbonate mixed with set amount of water.
Rate of oxygen produced
Volume produced/ time taken
Control variables in investigation into effect of light intensities on rate of photosynthesis
Carbon dioxide concentration (sodium hydrogencarbonate amount)
Temperature (putting in water bath)
Law of limiting factors
When a process depends on 2 or more factors, the rate of that process is limited by the factor which is in short supply.
Light intensity’s effect on photosynthesis graph
At first, no gas is released as rate of photosynthesis= rate of respiration (compensation point) Then the (as light intensity increases), rate of photosynthesis steadily increases up to a certain point in which it plateaus as another factor limits the rate.
Light intensity
Proportional to 1/ distance squared
Relationship between light distance and intensity of light
Inversely proportional
Carbon dioxide’s effect on photosynthesis rate graph
As CO2 concentration increases, so does rate of photosynthesis until plateaus as other factor limits rate.
This is because CO2 is a raw material needed for photosynthesis.