4.4.1.2 Rate of Photosynthesis Flashcards
What are the limiting factors of photosynthesis?
- Light intensity
- Concentration of carbon dioxide
- Temperature
- Amount of chlorophyll
- Less water - affects chloroplasts
Limiting factors of photosynthesis: Light intensity - describe the graph:
A = increase in light, increases the rate of photosynthesis, light = limiting factor
B = increase in light doesn’t change rate of photosynthesis, no longer limiting factor, line plateaus, light or CO2 could no longer be limiting factor
Limiting factors of photosynthesis: Concentration of CO2 - describe the graph:
A – no carbon dioxide, no photosynthesis
B – as carbon dioxide concentration increases, so does rate. - therefore CO2 is the limiting factor
C – increasing carbon dioxide concentration no longer increases rate of photosynthesis - therefore, it is no longer the limiting factor, line plateaus
Limiting factors of photosynthesis: Temperature - describe the graph:
- Initially as temperature increases so does the rate of photosynthesis. Particles have more kinetic energy. More frequent, successful enzyme collisions.
- Optimum = temperature goes to max rate.
- After an optimum temperature the rate of photosynthesis decreases and the enzymes that control photosynthesis denature. Temperature too high so enzymes involved in photosynthesis begin to denature, rate of photosynthesis decreases until 0.
Limiting factors of photosynthesis: Amount of chlorophyll
- The more chlorophyll the higher the rate of photosynthesis - so chlorophyll is limiting factor as rate of photosynthesis increases
- There is a limit to the amount of chlorophyll a leaf can hold - chlorophyll no longer limiting factor as amount of chlorophyll cannot increase and any increase wouldn’t affect the rate of photosynthesis
How does the amount of chlorophyll affect the rate of photosynthesis?
- More chlorophyll = more light absorbed for photosynthesis
= more photosynthesis = more glucose produced =more glucose converted to starch
= more substrates for respiration = more energy released for growth
= more crop yield. - Less water - affects chloroplasts
What is the process in which plants require oxygen?
aerobic respiration
Why are limiting factors important in the economics of enhancing conditions in greenhouses?
- Limiting factors are important in the economics of enhancing the conditions in greenhouses to gain the maximum rate of photosynthesis while still maintaining profit
- Greenhouses increase food production - give a large yield of crop per year
Name all the greenhouse conditions to maximise the rate of photosynthesis:
- Watering systems
- Hydroponics
- Shading
- Humidifiers
- Biological control
- Heater
- Sun
- Ventilation
Greenhouse conditions to maximise the rate of photosynthesis: Watering systems
Watering systems deliver a regular supply of water
Greenhouse conditions to maximise the rate of photosynthesis: Hydroponics
- Hydroponics: growing plants in mineral nutrient solutions without soil
- Controlled watering system where roots are grown in rock wool (a basalt based medium) and mineral rich water
Greenhouse conditions to maximise the rate of photosynthesis: Shading
- Helps control amount of light and temperature reaching the plants
- Blinds can be used to control the amount of light reaching the plants
- Special lights are used to increase the number of hours of light - these are switched off for approx. 7hrs, allowing plants to transport glucose that has been made
Greenhouse conditions to maximise the rate of photosynthesis: Humidifiers
- Humidifiers used to add moisture to the air
- Reduces transpiration
- Reduces the need for watering
Greenhouse conditions to maximise the rate of photosynthesis: Biological control
- Relatively closed growing environment so can use living organisms to control pests
- Instead of using pesticides to remove pests they can market their produce as organic by using natural insects to eat bugs and flies e.g. ladybirds eat greenflies this increases profit
Greenhouse conditions to maximise the rate of photosynthesis: Heater
- Increases temperature
- Temperature is controlled by sensors to within 0.1 degrees C
- Increases concentration of carbon dioxide if a paraffin heater is used. Higher concn of CO2 = potentially a faster rate of photosynthesis (if CO2 is the limiting rate of photosynthesis). Can also be used to increase the temperature on a cooler day and night.
Diagram of marram grass:
Diagram of a potometer:
Graph to show how carbon dioxide (limiting factor of photosynthesis) affects the rate of photosynthesis:
Graph to show how temperature (limiting factor of photosynthesis) affects the rate of photosynthesis:
Graph to show how light intensity (limiting factor of photosynthesis) affects the rate of photosynthesis:
