S8: Photosynthesis Flashcards
Definition of photosynthesis
Photosynthesis is the way plants make their own food using light
Word equation and chemical equation for photosynthesis
——————————Chlorophyll
Carbon dioxide + water —> glucose +oxygen
——————————– Sunlight
—————Chlorophyll
6CO² + 6H²O —> C⁶H¹²O⁶ + 6O²
————– Sunlight
Definition of factor
Factor: anything (living or nonliving) that affects something else
How is the carbon dioxide level on our planet prevented from becoming poisonous?
Photosynthesis
Meaning of photo and synthesis in photosynthesis
Photo = light Synthesis = produce/make
What 3 functions does photosynthesis carry out for the continued existence of life on earth?
- Photosynthesis results in plants giving off oxygen, which is essential for many living organisms
- It removes carbon dioxide from the air and prevents it from reaching a poisonous level.
- Photosynthesis provides food for most living organisms on earth.
How do plants photosynthesise?
- Plants take in carbon dioxide from the air through tiny pores on their leaves called stomata (singular stoma)
- Plants take in water from the soil through their roots.
- Sunlight is absorbed by the chloroplasts in the cells of the leaves of the plant.
- The green pigment chlorophyll, in the chloroplasts, allows the carbon dioxide and water to combine to form glucose.
- The energy for this reaction comes from sunlight.
- Oxygen is released and given off as a waste product.
What is required by humans to make the pigment haemoglobin
Iron is required by humans to make the pigment haemoglobin
What do plants require to make the pigment chlorophyll
Plants need a mineral called magnesium in order to make the pigment chlorophyll.
What can photosynthesis be described as?
Chemical and biological
It is a chemical process because there are new substances formed
Photosynthesis occurs in the chloroplasts of living cells where enzymes that are essential to the process are present. It is a biological process because it happens in living cells
What is the carbon cycle
What is important about carbon atoms
The constant recycling of atoms is known as the carbon cycle.
There is a fixed amount of carbon on Earth so one particular atom of carbon could be found in various different compounds at different times
Why is photosynthesis important in the carbon cycle? What does it do to carbon?
Photosynthesis is how carbon in the form of carbon dioxide gas gets fixed (caught up) in compounds such as food and fuels.
It is vital for keeping the carbon cycle going and therefore keeping life on earth going.
List the factors affecting photosynthesis and explain how they affect it
Carbon dioxide:
If carbon dioxide levels fall, the rate of photosynthesis will also fall because there will be less gas to take part in the photosynthesis reactions. If the carbon dioxide levels rise, the rate of photosynthesis will also rise because of the rise in gas available.
Temperature:
All biological processes are controlled by proteins called enzymes. Enzymes need a particular Temperature to work efficiently. Too low and they slow down including the rate of reaction. Too high and the Enzymes may be destroyed and so the reaction will stop.
Light:
Light provides the energy for the reactions to occur in photosynthesis. If the Light intensity is low, the rate of photosynthesis will be low due to the lack of energy. As the Light increases, so does the rate at which photosynthesis occurs.
What must you remember about energy in photosynthesis?
Energy is needed for atoms to bond together. So light energy is converted to chemical energy in food in the process of photosynthesis.
What is the point of greenhouses?what is added to greenhouses to increase the yield of their crops?
Greenhouses raise the temperature so that plants will photosynthesise more efficiently and produce better crops.
Growers also add carbon dioxide to greenhouses to increase the yield of their crops.
