B2.3 Photosynthesis Flashcards
Describe the process of photosynthesis
light energy is absorbed by a green substance called chlorophyll which is found in chloroplasts in some plant and algae cells
This energy is used by converting carbon dioxide from the air and water from the soil into sugar
oxygen in released as a by product
How may the rate of photosynthesis be limited by?
- shortage of light
- low temperature
- shortage of carbon dioxide
How can you change the light intensity to increase the rate of photosynthesis?
artificial lighting
How can you change the temperature to increase the rate of photosynthesis?
to warm up- heater or greenhouse - traps sun’s heat
to cool down- shades, ventilation
How can you change the carbon dioxide concentration to increase the rate of photosynthesis?
use a paraffin heater. As paraffin burns it makes carbon dioxide as a by product
What may some of the glucose produced in photosynthesis be converted into?
insoluble starch for storage
- ready for use when photosynthesis is not occurring like in winter
What is the equation for photosynthesis?
carbon dioxide + water —– glucose + oxygen
What are the 5 ways that plants use glucose?
- respiration
- making cellulose which strengthens cell walls
- making proteins
- to produce fat or oil for storage
- stored as insoluble starch
To produce proteins, what do plants also need?
nitrate ions that are absorbed from the soil
About what temperature do enzymes start to become damaged in plants?
45 degrees
Why do biologists use models in their research?
- it is possible to mimic large scale events on a small scale
- can be used to predict changes
Describe what factors a farmer should consider when building tunnels to grow plants in
consider limiting factors- CO2, temp, light
- light changes with type of plastic, colour and thickness of tunnels
- hight need heating or ventilation to control temp
- needs to have a source of CO2 gas
What do farmers need to consider before making decisions about the growing conditions for their plants?
- The cost of providing the conditions
- The effect of the conditions on profit
What happens if a plant does not get enough nitrates?
stunted growth
Name the 2 reactants in photosynthesis and state where each one comes from
carbon dioxide- air
water- soil
Where is chlorophyll found?
in chloroplasts in some plant and algae cells
What is the function of chlorophyll?
absorbs light energy which is used to convert carbon dioxide and water to glucose and oxygen
Name the substance that glucose can be converted into for storage and describe how you can test for the presence of this substance
insoluble starch
test with iodide: changes from brown to blue-black if starch is present
Why might a farmer put a paraffin heater in a greenhouse?
to increase carbon dioxide concentration to increase the rate of photosynthesis
How do plants produce proteins for growth?
use nitrate ions that are absorbed from the soil to make amino acids that are then joined to make proteins
This process require glucose from photosynthesis
Describe the shape of the rate of photosynthesis on a light intensity graph
As the light intensity increases the rate of photosynthesis increases up to a peak point- optimum
After this point any further increase in light intensity does not increase the rate of photosynthesis
Explain the effect of increasing the temperature has on the rate of photosynthesis
Increasing the temperature increases the rate up to a max production at 40 degrees
this is because enzymes have more energy and up to 40 degrees, temperature is a limiting factor
Increasing the temperature over 40 degrees decreases the rate of photosynthesis
because the high temperature denatures enzymes in the plant
Suggest how receiving more sunlight could result in plants producing more flowers per stalk
more energy is available for growth
Why do plants need magnesium ions for healthy growth?
to make chlorophyl which traps light energy
for photosynthesis
