Biology · OCR Paper 1
Photosynthesis
How green plants and algae make glucose by photosynthesis and so provide the food and biomass for life on Earth, what the reaction needs and produces, how to investigate it, and how temperature, light intensity and carbon dioxide concentration limit its rate. Matches OCR GCSE Biology A (Gateway Science) B1.4 (photosynthesis). Every lesson is for both Combined Science and separate Biology; the interaction of limiting factors on graphs is for the Higher tier only.
Lessons
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1
The Photosynthetic Reaction
Photosynthesis is the reaction that feeds almost every food chain on Earth. This lesson covers why photosynthetic organisms are the main producers of food and…
10 terms -
2
Rate of Photosynthesis and Limiting Factors
A plant does not always photosynthesise as fast as it could. This lesson explains how temperature, light intensity, carbon dioxide concentration and…
8 terms -
3
Investigating Light Intensity and Photosynthesis
This is the required practical on photosynthesis. This lesson describes how to use pondweed to investigate the effect of light intensity on the rate of…
8 terms
Key terms in this chapter
All 26, gathered from every lesson.
- Biomass
- The mass of living material in an organism or a food chain.
- Fix
- To join carbon dioxide into an organic compound, such as glucose, during photosynthesis.
- Photosynthesis
- The reaction in which plants use light energy to make glucose and oxygen from carbon dioxide and water.
- Producer
- An organism that makes its own food, such as a plant.
- Chlorophyll
- The green pigment in chloroplasts that absorbs light for photosynthesis.
- Chloroplast
- The part of a plant cell where photosynthesis happens.
- Endothermic reaction
- A reaction that takes in energy from its surroundings.
- Reactant
- A substance that is used up in a chemical reaction.
- Product
- A substance made in a chemical reaction.
- Glucose
- A sugar made in photosynthesis, which is a source of energy.
- Limiting factor
- A factor that is in short supply and so limits the rate of a reaction.
- Light intensity
- How bright the light is.
- Carbon dioxide concentration
- The amount of carbon dioxide in the air around a plant.
- Optimum temperature
- The temperature at which the rate of reaction is greatest.
- Denatured
- Having a changed shape so an enzyme can no longer work.
- Rate of reaction
- How fast a reaction happens.
- Plateau
- A flat part of a graph, where the rate has stopped rising.
- Greenhouse
- A glass building used for growing plants in controlled conditions.
- Pondweed
- A water plant, such as Elodea or Cabomba, used in photosynthesis experiments.
- Independent variable
- The variable that the investigator changes.
- Dependent variable
- The variable that is measured.
- Control variable
- A variable that is kept the same so the test is fair.
- Sodium hydrogencarbonate
- A chemical added to water to provide carbon dioxide.
- Reliable
- Giving similar results each time the investigation is repeated.
- Inverse square law
- The rule that light intensity falls in proportion to 1 divided by the square of the distance.
- Mean
- An average, found by adding the values and dividing by how many there are.