Photosynthesis Flashcards
Variables in an experiment
independent, dependent, control
Word equation of photosynthesis
Carbon dioxide + water → glucose + oxygen
Storage of glucose
Starch
Test for starch
Iodine test: color change from brown to dark blue
Procedure for testing if starch is present in a leaf
- Heat a plant leaf in boiling water for 30 seconds (this kills the leaf, stopping any chemical reactions)
- Add the leaf to boiling ethanol in a water bath for a few minutes
- Wash the leaf with water to rehydrate and soften the leaf and spread it onto a white tile.
- Add iodine solution from a dropping pipette.
- Colour of the iodine solution change from brown to dark blue.
Why do we boil the leaf before performing an iodine test?
To kill the leaf and stop any chemical reactions
Why do we add ethanol to the leaf before performing an iodine test?
The boiling ethanol dissolves the chlorophyll and removes the green color from the leaf so it is easy to see the change in color.
Test for essential components for photosynthesis - light
Test for essential components for photosynthesis - chlorophyll
variegated leaf
Steps to take before performing tests for photosynthesis
Word equation of respiration
glucose + oxygen → carbon dioxide + water
Purpose of soda lime in respiration test
Absorb carbon dioxide
Members in the food chain and energy transfer
Energy is transferred from the producer to the primary consumer and then the secondary consumer
Where does gas exchange in plants take place?
At the stomata
Describe gas exchange in plants during the day and at night.
During the day, plants undergo both photosynthesis and respiration as there is light. The rate of photosynthesis is higher than that of respiration. At night, plants only undergo respiration.
In a burning food test, the results obtained from this experiment are lower than the actual energy content of the food. Why?
During the experiment, some energy is lost to the air and some is used to heat the glass of the boiling tube instead of heating up the water.
