Biology notes on cell metabolism.

Essay by xstylinx November 2007

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*Metabolism:Term used to describe chemical reactions in a cell.

*Reactants:Chemicals that react with each other.

*Products:Chemicals produced at the end of a chemical reaction.

*Anabolic reaction:Reactions that involve the building up of complex molecules from simpler molecules. Enery is required. e.g photosynthesis*Catabolic reaction: Reactions where complex molecules are broken down into simpler molecules. These reactions realease energy.e.g respiration*Enzymes: Catalysts(proteins) which speed up chemical reactions without getting envolved in them.

-enzymes control metabolic reactions.

-They are proteins.

-Proteins are made up of long chains of amino acids, that fold over and take up a specific shape.

-Enzymes will only work if they have the correct shape to allow them to function properly.

*substrate:Substance an enzyme reacts with.

^^pH^^-Tends to change the shape of the enzyme and effect the rate an enzyme will carry out its function.

-Enzymes will only have its correct shape at a specific pH.

-The enzyme becomes less efficent on the other side of the pH.

^^Temperature^^-At low temp cell contents become solid, so enzymes cannot work.

-As temp increases so does rate of reaction because the substrate and enzyme get more energy.

-The temp that an enzyme works beast at is its optimum temp.

-above optimum temp enzymes denature and rate of reaction drops.

__________________________________*Immobilised Enzymes: Enzymes that are attached to eachother or an inert material.

Advantages of immobilised enzymes-Can recover enzymes easily- Enzymes can be reused-effiency of enzymes is not affected*Bioreactor-Large tank containing enzymes in an immobilised form used in industrial processes.

________________________________________*Active site- The part of the enzyme taht combines with the substrate.

Active Site Theory1.The substrate combines wih the active site of the enzyme.

2.The active site is induced slightly to make a better fit for the substrate.

3. The bonds in the substrate are altered...