Photosynthesis Flashcards
Name three factors that can limit the rate of photosynthesis.
Temperature
Carbon dioxide concentration
Light intensity
What is photosynthesis?
Photosynthesis is the chemical change which happens in the leaves of green plants. It is the first step towards making food.
What happens during photosynthesis?
Light energy is absorbed by chlorophyll
Absorbed light energy is used to convert carbon dioxide (from the air) and water (from the soil) into a sugar called glucose. Oxygen is released as a by-product
What are chloroplasts?
A plastid in green plant cells which contains chlorophyll and in which photosynthesis takes place.
What is glucose?
A simple sugar which is an important energy source in living organisms and is a component of many carbohydrates.
What is chlorophyll?
Chlorophyll is a green substance found in chloroplasts in some plant cells and algae.
What is glucose used for?
Some glucose is used for respiration, while some is converted into insoluble starch for storage. The stored starch can later be turned back into glucose and used in respiration.
What is starch?
An odourless, tasteless white substance occurring widely in plant tissue. It is a polysaccharide which functions as a carbohydrate store and is an important constituent of the human diet.
Can you use glucose for more than one purpose?
The glucose produced in photosynthesis may be used in various ways by plants and algae.
What is glucose needed for?
Glucose is needed by cells for respiration.
When is glucose not produced?
It is not produced at night when it is too dark for photosynthesis to happen.
What is glucose used to produce?
Cellulose - which strengthens the cell wall
Proteins - such as enzymes and chlorophyll
Besides glucose, what do plants need to make proteins?
Plants also need nitrates to make proteins. These are absorbed from the soil as nitrate ions.
What are plants?
Plants are multicellular organisms, just like animals. They also usually contain differentiated cells, tissues and organs.
What is the function of the epidermal tissue?
It covers the plant
What is the function of mesophyll?
Carries out photosynthesis
What is the function of xylem and phloem?
Transport of substances around the plant
Name three plant organs
Roots
Stems
Leaves
Are leaves adapted?
Leaves are adapted to absorbing sunlight for photosynthesis
What is the purpose of chlorophyll?
To absorb sunlight
What is the purpose of a leaf having a large surface area?
To absorb more light
What is the purpose of a stomata?
To let carbon dioxide diffuse into the leaf
What is the purpose of a leaf being thin?
Short distance for carbon dioxide to diffuse into leaf cells.
What is the purpose of having a network of veins?
To support the leaf and transport water and carbohydrates
