2.2 Biological molecules

• Monomers are smaller units which can create larger molecules.
• Polymers are made from lots of monomers which are bonded together.
• Examples of monomers include glucose, amino acids, and nucleotides.
• Examples of polymers include glucose, cellulose, and glycogen.
• To create polymers, a condensation reaction is used.
• drogen bonds to break and the active site to change shape and therefore enzyme substrate complexes won't form and the rate decreases for substrate concentration if there is a higher substrate concentration then there are more enzyme substrate complexes forming and the rate increases but if there is too high a substrate concentration then the enzyme can't accommodate all of the substrate molecules and the rate decreases for enzyme concentration if there is a higher enzyme concentration then there are more enzyme substrate complexes forming and the rate increases but if there is too high an enz
• The first mark in a condensation reaction is the joining of two molecules, creating a chemical bond, and removing water.
• Carbohydrates are the first biological molecules that need to be known.
• The three levels of size for carbohydrates are monosaccharides, disaccharides, and polysaccharides.
• Starch and cellulose are both found in plants but have different functions.
• Starch is a store of glucose that can provide chemical energy.
• Cellulose is a structural component of the cell wall that provides strength.
• Glycogen is the only polysaccharide found in animals and is a store of glucose mainly found in the liver and muscle cells.
• Starch and glycogen are both made from alpha glucose, but cellulose is made from beta-glucose.
• Starch and glycogen are both polysaccharides, which means they are large and insoluble.
• Cellulose has a different structure than starch and glycogen because it only contains one to four glycosidic bonds, forming long straight chains.
• Glycogen has a higher proportion of one to six glycosidic bonds, making it more branched and more readily hydrolyzed back into glucose.
• Triglycerides and phospholipids are two types of lipids that have a glycerol molecule and different fatty acid chains attached.
• Phospholipids have a fatty acid chain lost and a phosphate group attached to the glycerol molecule.
• Triglycerides form through three condensation reactions, losing three water molecules between each fatty acid and the glycerol molecule, and the bond that forms is called an ester.
• Examples of monosaccharides include glucose, fructose, and galactose.
• Examples of disaccharides include sucrose, maltose, and lactose.
• Examples of polysaccharides include starch, cellulose, and glycogen.
• The structure of alpha and beta glucose is important to know for AQA biology.
• The formula for glucose is C6H12O6.
• Glucose comes as two isomers, alpha and beta, which have the same molecular formula but different structures.
• Drogen and the ionic bonds to break, leading to the loss of tertiary structure and active site changes, which is described as enzyme denaturing.
• Insufficient substrate results in fewer collisions between the substrate and the enzymes, leading to a lower rate of reaction.
• Adding more substrate can increase the rate of reaction, but if the enzyme active sites are all in use or saturated, the rate remains constant.
• Enzyme inhibitors bind to an enzyme, either competitively or non-competitively, and lower the rate of reaction.
• Competitive inhibitors bind to the active site, preventing enzyme substrate complexes from forming.
• Non-competitive inhibitors bind to the allosteric site, causing the active site to change shape and preventing enzyme substrate complexes from forming.
• The biochemical test for starch involves adding iodine and observing the change from orangey brown to blue black.
• The biochemical test for reducing sugars involves adding benedict's reagent and heating it, with a positive result indicated by the change from blue to either green, yellow, orange or brick red.
• If the solution changes from blue to orange or brick red, it indicates the presence of a non-reducing sugar.
• A triglyceride is a lipid with three ester bonds, and can be either saturated or unsaturated.
• Saturated fatty acids have no double bonds between any of the carbon atoms, and hold the maximum amount of hydrogen.
• Unsaturated fatty acids have at least one double bond between the carbon atoms, but the number of carbon atoms must be stated in the exam to get the mark.
• The function of triglycerides is as an energy store, due to the large ratio of energy storing carbon to hydrogen bonds and the high ratio of hydrogen to oxygen atoms.
• Triglycerides do not affect the water potential and therefore do not affect osmosis, due to their large size and hydrophobic nature.