Photosynthesis Flashcards
What is photosynthesis?
The chemical change which happens in the leaves of green plants.
What can the absorption of energy from the sun through photosynthesis be described as?
An endothermic reaction.
What is the word equation for photosynthesis?
What can oxygen be described as?
. Sunlight
Carbon dioxide + water ——————> glucose + oxygen
. Chlorophyll
Oxygen can be described as a waste product.
What is the balanced symbol equation for photosynthesis?
6CO2+ 6H20 —> C6H12O6 + 6O2
What is glucose used for? (In plants)
Energy for Respiration
Converted to starch or oils for storage.
Can be converted to:
Cellulose for cell walls
Chlorophyll
Protein for growth
Describe the experiment used to find out if a plant needs light for photosynthesis.
Day 1
- Place tinfoil over a leaf using a paper clip.
- Place the plant in a wall lit place
Day 2
- Collect leaf that has been covered in tin foil
- Pour boiling water into a beaker and place the Leaf inside using forceps.
- After a few moments remove the leaf from the boiling water.
- Get a boiling tube and fill it with ethanol.
- Push the leaf into the ethanol and place the tube into the boiling water
- The ethanol should boil and the chlorophyll should be removed from the leaf.
- After 5-10 minutes remove the leaf from the boiling tube.
- Dip it into the boiling water to soften it.
- Lay the leaf out on a white tile, and drip iodine onto the leaf
- Wait a few moments for the iodine to change colour.
Describe the experiment used to find out if a plant needs chlorophyll for photosynthesis.
Day 1
- Find a plant with variegated leaves
- Place the plant in a wall lit place
Day 2
- Collect leaf
- Pour boiling water into a beaker and place the Leaf inside using forceps.
- After a few moments remove the leaf from the boiling water.
- Get a boiling tube and fill it with ethanol.
- Push the leaf into the ethanol and place the tube into the boiling water
- The ethanol should boil and the chlorophyll should be removed from the leaf.
- After 5-10 minutes remove the leaf from the boiling tube.
- Dip it into the boiling water to soften it.
- Lay the leaf out on a white tile, and drip iodine onto the leaf
- Wait a few moments for the iodine to change colour.
Describe the experiment used to find out if a plant needs carbon dioxide for photosynthesis.
- Get two geranium plants
- Next to each one, place a dish containing soda lime or sodium hydrogen carbonate
- Place a plastic bag over each plant to keep it air tight
- Place the plants in a well lit location and leave them for 24-48 hours
- Perform starch tests on both plants
The plant containing soda lime (which absorbs CO2) should have less starch, while the plant containing sodium hydrogen carbonate (which produces CO2) should have more starch.
Describe the experiment used to measure the rate of photosynthesis.
- Darken the room by closing the blinds and turning the lights off
- Cut a piece of edolea (pond weed) about 5cm long
- Attach a paper clip to the top end to weigh it down
- Add a spatula of sodium hydrogen carbonate into the test tube of water.
- Put the plant into the test tube with the cut end facing up.
- Place the test tube in a beaker of warm water
- Place a lamp 5cm away from the beaker. Remember to use a heat shield
- Count the number of bubbles given off in 1 minute
- Move the plant further away and count the number of bubbles given off again.
- Repeat until the plant is 50 cm away from the plant.
What are the 3 limiting factors of photosynthesis?
Light intensity
Temperature
Availability of CO2
List the structures of a leaf and their functions.
Cuticle
A thin waxy covering to prevent water loss
Upper Epidermis
Outermost layer of the leaf
Palisade mesophyll
The main site of photosynthesis
Vein (with phloem and Xylem)
Phloem transports sugar and Xylem transports water
Spongy mesophyll
Contains gas pockets to aid in respiration
Stomata
Allow for gas exchange
Guard cells
Open and close stomata depending on conditions.
Lower epidermis
Outermost layer of the leaf
You should know low to label these structures in a diagram.
What is the word equation for respiration?
Glucose + oxygen ——> carbon dioxide + water + energy
What is the photosynthesis-respiration ratio during the day?
Both occur, but the rate of photosynthesis is higher.
What is the photosynthesis-respiration ratio at night?
There is little light for photosynthesis
Therefore the ratio of respiration is higher
What is the photosynthesis-respiration ratio during dawn or duck?
The rate if photosynthesis and respiration is equal. This is the compensation point. Overall there is no gas exchange.
