Energy And Chemical Reactions

Energy and Chemical Reactions • Energy – Ability to move or change matter – Light, heat, chemical, mechanical and electrical energy

• Energy can be stored or released by chemical reactions

• Chemical reaction – Bonds are broken and new ones are formed making one or more different substances

• Reactants – Starting material

• Products – Newly formed substances; ending material

• Reactants Products • Energy is absorbed or released when chemical bonds are broken and new ones are formed.

• Metabolism – All the chemical reactions that occur within an organism

• Activation energy – Energy needed to start a chemical reaction – A chemical “push” that starts a chemical reaction

Enzymes • Catalysts – Reduce the activation energy of a chemical reaction

• Enzymes – Increase the speed of chemical reactions – Most are proteins – A catalyst – End in “-ase”

• Enzymes help organisms maintain homeostasis.

Enzymes cont. • Substrate – Substance on which an enzyme acts during a chemical reaction

• Active sites – Pockets in enzyme

• Enzyme’s shape determines its activity • Enzymes act only on specific substrates

Factors in Enzyme Activity • Any factor that changes the shape of an enzyme can affects its activity. – pH – Temperature