Bioenergetics Flashcards
State the balanced symbol equation for photosynthesis
6 CO2 + 6 H2O → C6H12O6 + 6 O2
State the word equation for photosynthesis
light
carbon dioxide + water → glucose + oxygen
Name 5 uses of glucose (for plants)
- Respiration
- Making Cellulose
- Making Amino Acids
- Stored as Oils or Fats
- Stored as Starch
How glucose is used for respiration (in plants)?
Respiration transfers energy from glucose = enables plant to convert rest of glucose into other useful substances
How glucose is used to make cellulose (in plants)?
Glucose is converted into cellulose for making strong plant cell walls
How glucose is stored as oils or fats (in plants)?
Glucose is turned to lipids (fats & oils) for storing in seed
How glucose is used to make amino acids (in plants)?
Glucose combined with nitrate ions (from soil) to make amino acids = made then into proteins
Where is starch stored and why is it stored?
Glucose turned into starch and stored in roots, stems & leaves, ready for use when photosynthesis isn’t happening (like in winter)
Why is starch better for storing than glucose?
Because starch is insoluble - cell with lots of glucose would draw in loads of water and swell up
What is a limiting factor?
Is something that can stop photosynthesis from happening any
Name 4 things the rate of photosynthesis is affected by?
- Temperature
- Intensity of light
- Concentration of carbon dioxide
- Chlorophyll
How can amount of chlorophyll in plant be affected?
Can be affect by disease or environmental stress (lack of nutrients)
How does amount of chlorophyll affect the rate of photosynthesis?
If chloroplasts are damaged or don’t make enough chlorophyll (e.g. due to disease), means rate of photosynthesis decreases as they can’t absorb as much light
In winter, what is usually the limiting factor?
Temperature
At night, what is usually the limiting factor?
Light
When it’s warm enough and bright enough, what is usually the limiting factor?
Carbon dioxide
Why does photosynthesis require light?
Because it provides energy
As the light level is raised, what happens to the rate of photosynthesis?
It increases steadily BUT only up to a certain point
Why might the rate of photosynthesis not increase as the light intensity increases?
Because either temperature or CO2 level is a limiting factor
As the CO2 level is raised, what happens to the rate of photosynthesis?
It increases steadily BUT only up to a certain point
Why does the temperature affect the rate of photosynthesis?
Because it affects enzymes involved
What does it mean if the limiting factor is temperature?
Means the temperature is too low
Why does increasing the temperature make the rate of photosynthesis increases?
Because the collisions between enzymes and substrates occur more frequently
What happens to the rate of photosynthesis when a plant gets too hot and why?
Enzymes become denatured causing photosynthesis to stop completely