Download Science M2 Science Photosynthesis summary notes

M2 Science ~ Photosynthesis in Plants & absorption & transportation of water
Objectives:
 Explore how plants need carbon dioxide, water and light for photosynthesis in
order to make biomass and oxygen
 Describe the absorption and transport of water and mineral salts in flowering
plants
Notes
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Photosynthesis is the way that plants make food, using energy from light.
Some of the food that is made becomes new biomass in the plant.
Biomass is the amount of matter in a living thing.
Plants use water and carbon dioxide in photosynthesis.
Carbon dioxide {a gas} is used in the production of starch.
Plants make food {glucose, a type of sugar, which is stored as starch} and
oxygen {a gas} by photosynthesis.
Plants produce oxygen when light shines on the leaves.
Plants produce starch in their leaves when light shines on them.
Leaves are adapted to carry out photosynthesis.
Leaves are green because they contain the green pigment chlorophyll,
which absorbs energy from light.
Leaves have tiny holes in their lower surfaces, called stomata, which allow
carbon dioxide to get into the leaf from the air.
A good way to find out if a water plant is photosynthesizing is to see if it
gives off bubbles of oxygen.
If photosynthesis is happening at a faster rate, then more oxygen is given off
per minute.
Minerals in the soil are needed by plants to survive.
The roots absorb water and minerals from the spaces between soil particles.
Roots anchor a plant in the ground.
Roots can store food for the plant.
Roots can sometimes survive harsh conditions that kill the above-ground
parts of the plant.
 Water and minerals are transported from a plant’s roots to its leaves inside
long, hollow tubes called xylem vessels.
 Water is drawn up through the plant by the leaves and the veins in a leaf
contain xylem vessels.
 The movement of water through a plant is called the transpiration stream.
 Wood is made up of xylem vessels.
 Starch can be detected with dilute iodine solution.
 A leaf must be decolourised and softened before it is tested for starch.
 A plant must be destarched before using it in a photosynthesis investigation.
 The equation for photosynthesis is:
Carbon Dioxide + Water →→sunlight & chlorophyll→→Glucose + Oxygen
N.B. Respiration (how an organism creates energy) is the reverse of
photosynthesis.
Read over the above summary each night plus additional notes to
ready yourself for the Unit test.