Y3Biology_BiomoleculesFINAL

Biomolecules Notes Why is there a need for food? • Food provides energy for vital activities. • Food provides raw materials to make new cells / substances • Food helps organisms stay healthy. Carbon Compounds • Organic compounds: Compounds built from Carbon (C) and Hydrogen (H). • In living mass, carbon is the third most abundant element by mass, after oxygen. • Carbon has a unique collection of properties that make life possible o Can form stable bonds with many elements due to their 4 valence electrons. o Can form long chains, which are used for storage of energy. § C-C-C-C-C-C Macromolecules • Polysaccharides and proteins are the macromolecules that have been introduced in this topic. • Chemically described as polymers • Made by linking together similar building blocks called monomers o Proteins (polymers) are built from amino acids (monomers) o Polysaccharides (polymers) are built from monosaccharide sugars (monomers) Properties (Structures, Properties, Functions)

• The type of macromolecule depends upon the type of monomer from which it is built. • The order in which the monomers are combined decides the shape of the macromolecule. • The shape of the macromolecule decides its biological properties and determines its role in cells. - Monomers are linked together by condensation reactions, a reaction in which the elements of water are removed. - Hydrolysis reactions are the reverse reactions that require water and results in the release of individual monomers again. Carbohydrates (hydrated Carbon) • largest group of organic compounds • General Formula: Cx(H2O)y • Carbohydrates are needed: o as a substrate for respiration (to provide energy) o to form supporting structures (e.g. cell wall in plants) o to be converted into other organic compounds such as amino acids & fats o for the formation of nucleic acids in DNA o to synthesize lubricants (e.g. mucus) o to synthesize nectar in some flowers • contains three main elements: Carbon, Hydrogen, Oxygen Monosaccharides • Monosaccharides are carbohydrates with relatively small molecules. • Properties: o All monosaccharides are reducing sugars. o Monosaccharides taste sweet and are soluble in water. • Examples: o Glucose § especially important § all cells use glucose in respiration § our bodies transport glucose in blood o Fructose § also found in cells § sweetest common sugar o Galactose § forms part of glycolipids and glycoproteins Disaccharides • Disaccharides are carbohydrates made of two monosaccharides combined together. • A molecule of water is removed when two monosaccharides combine, so the reaction is called a condensation reaction. o Remove a molecule of water from glycosidic bond § The bond formed between the monosaccharides is called a glycosidic bond.

• Properties: o soluble in water • Examples: o Sucrose: made up of glucose and fructose § An important sugar § transported in the phloem tissue to stems, roots or carbohydrate storage sites in the plant § the “sugar” that huma