Biological molecules

• monomers are smaller units which can create larger molecules
• monomers are smaller units which can create larger molecules
• polymers are made from lots of monomers bonded together
• monomers can be glucose, nucleotides or amino acids
• condensation reaction is when two molecules join together creating a chemical bond and removing water
• a hydrolysis reaction breaks a chemical bond between two molecules and involves the use of water
• carbs include monosaccharides disaccharide and polysaccharides
• disaccharides are formed by condensation reactions between two monosaccharides
• monosaccharides include glucose, fructose and galactose
• disaccharides include sucrose, maltose and lactose
• polysaccharides include glycogen, cellulose and starch
• isomers: same molecular formula but different structure
• disaccharide: two monosaccharides joined by a glycosidic bond created by a condensation reaction
• glucose + glucose = maltose + water
• glucose + galactose = lactose = water
• glucose + fructose = sucrose + water
• starch : provides chemical energy for plants
• glycogen: provides store of glucose for animals
• cellulose: provides structural strength for plants
• starch: a polysaccharide with alpha glucose
• starch: amylose 1-4 glycosidic bonds(unbranched) amylopectin 1-4 and 1-6 glycosidic bonds (branched)
• starch: helix can compact to fit a lot of glucose in a small space, branched structure increases surface area for hydrolysis back to glucose. Insoluble- won't affect water potential
• cellulose: a polysaccharide made of beta glucose
• cellulose: 1-4 glycosidic bonds
• cellulose: polymer makes long straight chains. Chains are held in parallel by many hydrogen bonds to form fibrils
• Cellulose: Many hydrogen bonds provide collective strength. Insoluble- won't affect water potential
• Glycogen: a polysaccharide made from alpha glucose with 1-4 and 1-6 glycosidic bonds
• Glycogen: Branched structure increases surface area for fast hydrolysis back to glucose. Insoluble- won't affect water potential
• triglyceride: an ester formed from 3 fatty acids and 1 glycerol
• phospholipid: 2 fatty acids, 1 glycerol and a phosphate group
• Triglycerides are formed via the condensation reaction between one molecule of of glycerol and 3 fatty acids
• Saturated fatty acids: the hydrocarbon chains has only single bonds between carbons
• Unsaturated fatty acids: the hydrocarbon chain consists of at least one double bonds between carbons
• Properties of triglycerides ENERGY STORAGE: due to the large number of energy storing carbon hydrogen bonds compared to the number of carbon atoms a lot of energy is stored in the molecule
• properties of triglycerides: due to the high ratio of hydrogen to oxygen atoms they act as a metabolic water source. They can release water if they are oxidised. This is essential for animals in the dessert such as camels
• Tryglicerides do not affect water potential or osmosis. This is because they are large and hydrophobic making them insoluble in water.
• Lipids(triglycerides) have a relatively low mass. Therefore a lot can be stored without increasing the mass and preventing movement
• Phospholipids: hydrophilic head due to negative charge on phosphate group
• Phospholipids attract water and repel fats as it is charged. The fatty acid chain is not charged. It is known as the hydrophobic tail and it repels water but will mix with fats
• Phospholipids have two charged regions so they are polar. In water they are positioned so that the heads are exposed to water and the tails are not. This forms a phospholipid bilayer membrane structure which makes up the plasma membrane around cells.