Proteins and enzymes

Variety of proteinsThe variety of shapes and functions arises from the different sequences of amino acids each protein has.

Functions of proteinsMost of the proteins in your body can be grouped into four categories based on the function they carry out.Structural - Give strength and support to cellular structures e.g membrane proteins give membranes their shape and strengthEnzymes - Act as biological catalysts to speed up chemical reactions in cells e.g amylase speeds up the breakdown of starch moleculesHormones - Carry specific messages in the bloodstream e.g insulin signals to the liver to store excess glucoseAntibodies - Provide specific defence against body invades such as certain bacteria or viruses

EnzymesEnzymes work as biological catalysts. This means that they  speed up the chemical reaction.Enzymes are made of proteins and are made by all living cells without them reactions in life would happen too slowly for life.3 properties of catalysts are...- Speed up chemical reactions- Less energy is needed in a chemical reaction - lowers the activation energy- The catalyst is unchanged at the end of the reaction

Enzyme SpecificityEnzymes are specific which means that they only work on one substrate molecule. The shape of the active site is complementary to the shape of the substrate which means that they fit together exactly.Factors affecting enzyme activityThe optimum (condition an enzyme works best at) is 37 C. If enzymes go too high above the optimum then they become denatured which means that the site of the active site is altered and they can no longer fit together. Enzymes are also affected by pH. Most enzymes work best at around 5-9 pH level and there is optimum is around pH 7 (neutral)

Key WordsActive Site - Position on the surface of an enzyme where specific molecules can bind.Catalyst - Something that speeds up chemical reactions by reducing the energy required for it.Denatured - Change in the shape of molecules which means they can no longer be used.Enzyme - Protein produced by all living cells that acts as a biological catalystOptimum - The temperature of pH that an enzyme works best at.Product - Substance made by an enzyme reactionSpecific - Each enzyme works on one substrate onlySubstrate - The substance an enzyme works best onHormones - Protein released as an endocrine gland into the blood as a chemical messengerAntibodies - Protein involved in defence for the body

Proteins

ENZYMES

Defintions