4. Photosynthesis Flashcards
(30 cards)
Provide the definition of Photosynthesis.
Process by which green plants manufacture their own food using radiant energy.
Give the word equation of Photosynthesis.
Carbon dioxide+ Water-> Glucose+ Oxygen
Give the chemical equation of Photosynthesis.
6CO2+ 6H2O -> C6H12O6+ 6O2
Name the 5 requirements for photosynthesis and why.
- Carbon dioxide: diffuses into leaves of plants
- Water: inorganic substance absorbed from soil by roots
- Light energy: absorbed from sun by leaves
- Chlorophyll: green pigment inside chloroplasts
- Enzymes: found inside chloroplasts
Name and explain the 2 products of Photosynthesis.
-Glucose: carb formed, converted and stored as starch in plants and glycogen in animals.
- Oxygen: gas released back in atmosphere from leaves
Give the 7 parts and functions of Chloroplast.
- Thylakoid: disc shaped membrane containing chlorophyll.
- Granum: stack of thylakoids
-Lamella: membranes make up thylakoids - Stroma: liquid part of chloroplast
- Starch granule: glucose stored as starch
- Chloroplast DNA: Contain genetic info
- Double membrane: protect chloroplast to allow substance to move in and out.
Name the 2 phases of Photosynthesis.
- Light dependent
- Light independent
Where does the light dependent phase take place?
Grana of chloroplast
What is oxygen used for in the light dependent phase.
- Form ATP
- Split water
What do you call the splitting of water?
Photolysis
What happens in the Light dependent phase?
- Light energy absorbed by chlorophyll
- Oxygen released, hydrogen joins into carrier molecule
Explain the light independent phase.
- Hydrogen combines with Co2 to form glucose.
- ATP from light phase to provide energy
- Take place in stroma of chloroplast
Give 3 differences between light and dark phase.
- Light: grana, light required, Phosphorylation -> ATP produced.
- Dark: stroma, light not required, excess glucose stored as starch
Name the 3 environmental factors affecting rate of photosynthesis.
- Light intensity
- Concentration of Co2
- Temperature
Explain how light intensity affects the rate of photosynthesis.
- low light intensity, low rate
- light increase, rate increase up to certain point
- optimum point, occur most rapidly
-past optimum= rate stays constant
Give 2 limiting factors of light intensity.
- Water
- Carbon dioxide
Explain how CO2 affects rate of photosynthesis.
- Low CO2, low rate
- CO2 increase, rate increase up to certain point
- Optimum, occur most rapidly
- past optimum= rate stays constant
Give 3 limiting factors of CO2 concentration.
- Toxic effect of CO2
- Insufficient water
- insufficient light
Explain how Temp affects the rate of photosynthesis.
- Low temp, low rate
- Temp increase, rate increase
- optimum= rate at max
- past optimum= decreased rate
What is the toxic effect of Temperature?
Enzymes denature and won’t function.
How does a Greenhouse system maintain optimal levels?
- Artificial light to improve light
- Shade clothes to reduce light
- Heaters to increase temp.
- Pump in CO2 to increase concentration.
How do you destarch a plant?
Place plant in dark cupboard for 48 hours.
Why do you destarch a plant?
- Prove that starch present at end of investigation is due to photosynthesis occuring and not from before.
What does destarching a plant increase?
- Validity/fairness
