Biology

Many plant cells contain green chloroplasts. Chloroplasts contain chlorophyll.

Chemical Reactions in chloroplasts make sugars.

Photosynthesis takes place in chloroplasts

Photosynthesis uses Carbon Dioxide and Water

Carbon Dioxide enters through the stomata in the leaves.

Oxygen is released in photosynthesis

Water can move in and out of cells

Water inside cells keeps their shape

A plant wilts when it loses too much water

Plants lose water through their stomata

Water can enter or leave by diffusion or osmosis

Osmosis only works through a partially permeable membrane

Water loss from plants is called transpiration

Phloem cells carry dissolved food to roots

Water enters plants through root hairs

Xylem cells carry water up stems.

Energy in plants and animals is transfered in food chains and webs

Food chains rarely exceed five links

Pesticides can build up in food chains

Intensive farming uses insecticides, herbicides and artificial fertilisers

Intensive farmingis very efficient

Hydroponics is an example of intensive farming

Organic Farming does not use manufactured chemicals

Pyramids of biomass and number show different trophic levels

Each trophic level 'loses' energy

The energy in biomass can be used as fuels called biofuels, for example to power buses

Alcohol from fermenting sugar cane can be used as a biofuel

Fast growing trees can fuel power stations

Carbon and nitrogen are recycled natually

Carbon Dioxide id taken out of the air during photosynthesis and is put into  air during burning of fossil fuels respiration

Nitrogen is put into the air by denitrifying bacteria  and is removed from the air by nitrogen-fixing bacteria

Bateria and fungi are decomposers

Decomposers cause dead bodies to decay

Decay is speeded up in warm damp conditions

The decay of food can be slowed down or stopped by methods of food preservation

Food Preservation methods slow down or stop the growth or bacteria and fungi