Merabolism and active transport

Metabolism

The sum of all the reactions that happen in a cell or the body. These reactions are controlled by enzymes. Energy required for these reactions supplied by respiration

Anabolic

Building up molecules

Usually endothermic reactions

Catabolic

Breaking down molecules

Usually, exothermic reactions

Transport into cells

The cell membrane is selectively permeable, controlling what goes in and out of the cell. It is a phospholipid bilayer with proteins scattered with it.

Diffusion

The net movement of particles from a region of higher concentration to a region of lower concentration. This is a passive process - requiring no imput of energy.

Lungs WIE

Oxygen from air and carbon dioxide from blood

Small intestine WIE

Small, digested food molecules diffuse into the blood

Placenta WIE

Food and oxygen from mother into foetus, carbon dioxide from foetus to mother

Gills WIE

Oxygen from water and carbon dioxide from blood

Nerves WIE

Transmitter substamces diffuses across synapse from one neurone to the next

Leaves WIE

Carbon dioxide and oxygen.

Water lost by evaporation

Roots WIE

Water and mineral ions

Osmosis

The net movement of water molecules from a dilute solution (an area of higher water concentration) to a concentrated solution (an area of lower water concentration) across a partially permeable membrane.

Percentage change

Mass after - mass before——————————— x 100

Mass before

Active transport

The movement of substances from a lower concentration to a higher concentration (= against the concentration gradient). This will take place through protein pumps in the cell membrane and involves the cell using energy (ATP)