B1.4.1 Photosynthesis Flashcards
What do plants have to take in to make food?
- Carbon dioxide
- Water
How do plants obtain these substances?
C02- diffuses from the air into the plant through the stomata
H20- enters the roots from the soil through root hair cells via osmosis
When these substances react, what do they produce?
Oxygen- some is used during respiration, rest is a waste product released back into the environment
Glucose- used as a food source
What is the word equation for photosynthesis?
Carbon dioxide + water —> glucose + oxygen
What is the symbol equation for photosynthesis?
6CO2+6H20 —> C6H12O6 + 6O2
Where does photosynthesis occur?
Inside the plants chloroplasts, meaning that it only occurs in the leaf but slightly in the green stem too
Why are leaves and stems green?
Since they contain the pigment chlorophyll in their chloroplasts
Where does glucose store energy?
Within it’s chemical bonds
What is the first main stage of photosynthesis reactions?
Energy transferred from light splits water molecules into oxygen gas into hydrogen ions
What is the second main stage of photosynthesis reactions?
C02 gas combines with hydrogen ions to make glucose
What type of reaction is photosynthesis?
Endothermic
What does this type of reaction mean?
It means that energy must be transferred from the surroundings to keep it going.
What is a photometer?
An instrument for measuring light intensity
What is phototropism?
the phenomenon by which the plant bends in the direction of light
What does photoconductive mean?
A material whose resistance decreases when it absorbs light
Explain why photosynthesis can’t occur in root cells?
They don’t have access to light energy from the sun, which is required for the process of photosynthesis to happen.
State three ways plants use glucose:
- In respiration
- to convert into other sugar molecules
- to convert into starch, a store of energy
Compare respiration and photosynthesis
Photosynthesis is the opposite of aerobic respiration, in the sense that their reactions are the other way around. Photosynthesis’ products - carbon dioxide and water - are aerobic respiration’s reactants, and its’ products - glucose and oxygen - are the reactants in photosynthesis.
Define photosynthesis
The process by which plants harness the energy from the sun and transfer this energy into a useable food source in the form of glucose that can be stored as starch
