Biology- Biological reactions

Photosynthesis

How green plants make their own food (glucose) using sunlight. It also releases oxygen.

Word Equation (Photosynthesis)

Carbon Dioxide + Water + Sunlight → Glucose (Sugar) + Oxygen

Carbon Dioxide

A gas from the air, enters through tiny holes in leaves.

Water

Taken from the soil by roots.

Sunlight

Energy from the sun, trapped by the chlorophyll in leaves.

Glucose (Sugar)

Food for the plant, used for energy and growth. Can be stored as starch.

Oxygen

A gas released into the air.

Where Photosynthesis Happens

Mostly in the leaves, in tiny parts of the cells that contain the green stuff.

Importance of Photosynthesis

Provides food for plants (which then feed animals), makes the oxygen we breathe, and takes carbon dioxide out of the air.

Leaves

To catch sunlight and make food through photosynthesis.

Flat and Wide Leaves

To catch lots of sunlight.

Thin Leaves

So gases can get in and out easily, and light can reach the chlorophyll.

See-through Top of Leaves

Lets light get to the cells inside.

Waxy Coating of Leaves

Stops too much water from escaping.

Packed Cells in Leaves

Layers inside with lots of the chlorophyll to trap sunlight.

Air Spaces in Leaves

Gaps inside for gases to move around.

Tiny Holes (Stomata)

Let carbon dioxide in and oxygen out. They can open and close.

Veins in Leaves

Carry water to the leaf and sugar away from it.

Xylem

The xylem transports water and minerals from the roots up the plant stem and into the leaves.

In a mature flowering plant or tree, most of the cells that make up the xylem are specialised cells called vessels.

Vessels:

• Lose their end walls so the xylem forms a continuous, hollow tube.

• Become strengthened by a chemical called lignin. The cells are no longer alive. Lignin gives strength and support to the plant. We call lignified cells wood.

Transport in the xylem is a physical process. It does not require energy.

Plant Minerals

Important tiny bits from the soil that plants need to grow healthily.

Nitrates

Help make proteins for growth. If a plant doesn't get enough, it will be small and yellow.

Magnesium

Part of the green stuff that traps sunlight. Not enough means yellow leaves.

Phosphates

Help with roots and making energy. Not enough means poor growth and maybe purple leaves.

Potassium

Helps control water and many plant jobs. Not enough means yellow edges on leaves.

Aerobic Respiration

How living things use oxygen to break down glucose (sugar) to get energy.

Word Equation (Aerobic Respiration)

Glucose + Oxygen → Carbon Dioxide + Water + Energy

Where Aerobic Respiration Happens

Mostly in tiny parts of the cells.

Importance of Aerobic Respiration

Provides lots of energy for all the things living things do, like growing and moving.

Anaerobic Respiration

How living things get a small amount of energy from glucose when there's no oxygen.

Where Anaerobic Respiration Happens

In the main part of the cell.

Importance of Anaerobic Respiration

Lets things get some energy when there's no oxygen. Yeast using this helps us make bread and alcohol.