B4 Photosynthesis and Limiting Factors (page 50) Flashcards
Photosynthesis produces what?
Glucose - using light.
What do photosynthesis use energy for?
It uses energy to change carbon dioxide and water into glucose and oxygen.
Where does Photosynthesis take place?
It takes place in Chloroplasts in green plant cells - they contain pigments like chlorophyll that absorb light.
During photosynthesis, how is energy transferred to the chloroplasts?
From the environment by light
Photosynthesis is endothermic - what do this mean?
it means energy is transferred from the environment in the process
What is the ‘word equation’ for Photosynthesis?
Carbon Dioxide + Water »_space;» Glucose + Oxygen
What is the symbol equation for photosynthesis?
6CO2 + 6H20 (light)
»_space;»> C6 H12 O6 + 6O2
Plants use Glucose in five main ways, name them?
1) For respiration
2) Making Cellulose
3) Making amino acids
4) Stored as oils or fats
5) Stored as starch
How do plants use Glucose for respiration?
Respiration transfers energy from glucose (see page 54), which enables the plants to convert the rest of the glucose into other useful substances.
How do plants use Glucose for making Cellulose?
Glucose is converted into cellulose for making strong plant cell walls (see page 11).
How do plants use Glucose to make Amino Acids?
Glucose is combined with Nitrate ions (absorbed from the soil) to make amino acids, which are then made into proteins.
How do plants use Glucose to store oils or fats?
Glucose is turned into Lipids (fats and oils) for storing in seeds.
How do plants use Glucose to store Starch?
Glucose is turned into starch and stored in roots, stems and leaves, ready to use when Photosynthesis isn’t happening, like in the winter. Starch is insoluable, which makes it much better for storing than glucose. - a cell with lots of glucose in would draw in loads of water and swell up.
What affects the rate of Photosynthesis?
Limiting Factors
How is the rate of photosynthesis affected?
By intensity of light, oncentration of CO2 and temperature.
What is meant by the Limiting factor of photosynthesis?
any of the three factors
intensity of light
concentration of co2
temperature
(this just means that it’s stopping photosynthesis from happening any faster).
The limiting factors have a combined effect on the rate of photosynthesis, but which factor is limiting at a particular time depends on what?
Depends on the environmental conditions, at night, in winter, if its warm enough, bright enough, the amount of co2 is usually limiting.
Chlorophyll can also be a limiting factor of photosyntheses, why?
The amount of Chlorophyll in a plant can be affected by disease (e.g. infection with the tobacco mosaic virus) or environmental stress stuch as a lack of nutrients.
These factors can cause chloroplasts to become damaged or to not make enough Chlorphyll. This means the rate of photosynthesis is reduced because they can’t absorb as much light.
Name the products of Photosynthsis? (2 marks)
Glucose (1 mark)
Oxygen (1 mark)
Apart from temperature, name three other limiting factors of photosynthesis (3 marks)
Light Intensity (1 mark)
Volume of CO2 (1 mark)
amount of Chlorophyll (1 mark)
