1.1 - Biological Compounds

• Monomers are smaller units that can create larger molecules, while polymers are made from lots of monomers bonded together
• Examples of monomers include glucose, amino acids, and nucleotides
• Polymers created from monomers include starch, cellulose, glycogen, proteins, DNA, and RNA
• To create polymers, a condensation reaction is used, involving joining two molecules, creating a chemical bond, and removing water
• Hydrolysis is the process of breaking apart or splitting the monomers, involving breaking a chemical bond between two molecules using water
• Carbohydrates are the first biological molecules to study, consisting of monosaccharides, disaccharides, and polysaccharides
• Monosaccharides include glucose, fructose, and galactose; disaccharides include sucrose, maltose, and lactose; polysaccharides include starch, cellulose, and glycogen
• Alpha and beta glucose are isomers with different structures, affecting the position of hydrogen and hydroxyl groups on carbon atoms
• Disaccharides are formed by a condensation reaction creating a glycosidic bond between two monosaccharides
• Maltose is made from glucose + glucose, lactose from glucose + galactose, and sucrose from glucose + fructose
• Polysaccharides like starch, cellulose, and glycogen have different structures and functions in plants and animals
• Starch is a store of glucose, cellulose provides structural strength in plant cell walls, and glycogen is a glucose store in animals
• Starch and glycogen are made from alpha glucose, while cellulose is made from beta glucose, with different glycosidic bonds
• Starch has both one to four and one to six glycosidic bonds, while cellulose only has one to four bonds
• Amylose is unbranched and forms a helix, amylopectin is branched for more enzyme attachment, cellulose forms strong fibrils due to hydrogen bonds
• Glycogen is highly branched for quick hydrolysis back into glucose, important for animals needing energy
• Lipids include triglycerides and phospholipids, with triglycerides having three fatty acid chains and a glycerol molecule
• Triglycerides form through three condensation reactions, losing three water molecules and forming three ester bonds
• Saturated fatty acids have no double bonds between carbon atoms, while unsaturated fatty acids have at least one double bond
• Triglycerides function as an energy store due to high energy-storing carbon-hydrogen bonds and metabolic water source, repel water, and have low mass compared to other tissues
• Lipids have a very low mass compared to other types of tissue in the body, allowing for efficient energy storage without increasing mass as much as extra muscle would
• Phospholipids have a unique structure with a phosphate group that gives them different properties compared to triglycerides
• Phospholipids have a hydrophilic head that attracts water and a hydrophobic tail that repels water, allowing them to form a bilayer in water
• Proteins are polymers made up of amino acid monomers
• Amino acids have a central carbon with an amine group (NH2), a carboxyl group (COOH), a hydrogen atom, and an R group
• To form a dipeptide, two amino acids bond together in a condensation reaction, forming a peptide bond
• The primary structure of a protein is the sequence of amino acids in a polypeptide chain
• The secondary structure of a protein involves folding or twisting of the primary structure, held in place by hydrogen bonds
• The tertiary structure of a protein is a unique 3D shape held in place by ionic, hydrogen, and disulfide bonds
• The quaternary structure of a protein involves multiple polypeptide chains held together by the same bonds as the tertiary structure
• Enzymes are proteins with a specific active site that catalyze reactions by lowering the activation energy
• Enzymes have a unique shape in their active site that is complementary to a specific substrate
• The induced fit model explains how enzymes slightly change shape to bind with substrates and lower the activation energy
• Factors affecting enzyme-controlled reactions include temperature, pH, substrate concentration, enzyme concentration, and inhibitors
• Temperature affects enzyme activity by influencing the rate of collisions between enzymes and substrates
• Substrate concentration affects enzyme activity by determining the rate of collisions between enzymes and substrates
• pH levels outside the optimum range can denature enzymes by interfering with the charges in the amino acids at the active site
• Enzyme concentration affects enzyme activity by determining the availability of active sites for substrates
• Competitive inhibitors bind to the active site of an enzyme, while non-competitive inhibitors bind to the allosteric site, altering the enzyme's shape
• Biochemical tests for molecules include the iodine test for starch, which turns from orange-brown to blue-black in the presence of starch