Biology Unit 3 PDF

10/3/24, 9:27 PM Biology unit 3.pdf Biology unit 3.pdf The Nature of Matter Description Matter is anything that has mass and takes up space. The basic form of matte...

10/3/24, 9:27 PM Biology unit 3.pdf Biology unit 3.pdf The Nature of Matter Description Matter is anything that has mass and takes up space. The basic form of matter is an atom, which contains subatomic particles called proto ns, neutrons, and electrons. Key Points Atoms are the simplest form of a substance and cannot be broken d own further. Protons are positively charged and have the same mass as neutron s, which carry no charge. Electrons are negatively charged and are constantly moving around the nucleus. Elements are assigned symbols and have a specific number of prot ons, known as the atomic number. Isotopes are atoms of the same element with a different number of neutrons. Ions are atoms that have a positive or negative charge due to the lo ss or gain of electrons. Compounds are formed when two or more elements bond together. Chemical Bonds Ionic bonds are formed when one or more electrons are transferred from one atom to another. Covalent bonds are formed when electrons are shared between ato ms. Molecules are formed when atoms are joined together by covalent bonds. Properties of Water Water has a partial negative charge on one end and a partial positi ve charge on the other, making it a polar molecule. The partial charges cause water molecules to attract each other, fo rming hydrogen bonds. This cohesion and adhesion of water molecules is responsible for im portant properties like surface tension and the ability to transport su about:blank 1/4 10/3/24, 9:27 PM Biology unit 3.pdf bstances. Enzymes Description Enzymes are proteins made up of amino acids that act as organic cat alysts, speeding up chemical reactions in living organisms. Key Points Enzymes have a specific shape that matches only one substrate, like a "lock and key" mechanism. Enzymes lower the activation energy required for a reaction to occu r, allowing it to proceed more quickly. The enzyme-substrate complex forms, the reaction occurs, and the product is released, leaving the enzyme free to work again. Enzymes are essential for all metabolic processes in living organism s. Factors Affecting Enzyme Activity Temperature: Increasing temperature can denature the enzyme, ch anging its shape and rendering it non-functional. pH: Enzymes have an optimal pH range for activity, and deviations c an cause denaturation. Substrate concentration: Increasing substrate concentration increas es the rate of reaction up to a point. Enzyme Kinetics The rate of enzyme action can be measured by the number of prod uct molecules formed per second. Graphs can show the influence of temperature and pH on enzyme a ctivity, with an optimal point for maximum activity. Monomers and Polymers Description Monomers are small molecules that can be bonded together to form l arger molecules called polymers. Carbohydrates Monomers: Glucose, sucrose Polymers: Starch, glycogen Function: Short-term energy storage and structure about:blank 2/4 10/3/24, 9:27 PM Biology unit 3.pdf Lipids Monomers: Glycerol, fatty acids Polymers: Fats, oils, waxes Function: Long-term energy storage, cell membrane components, h ormones Proteins Monomers: Amino acids Polymers: Polypeptides Function: Growth, repair, enzymes, hormones, antibodies, structural c omponents Nucleic Acids Monomers: Nucleotides Polymers: DNA, RNA Function: Genetic information storage and transmission Chemical Reactions and Enzy mes Description Chemical reactions involve the transformation of one set of substanc es (reactants) into another set of substances (products). Chemical Equations Reactants: The starting materials Products: The end result of the reaction A chemical equation represents the reaction using chemical symbol s and formulas. Enzyme Function Enzymes act as catalysts, speeding up the rate of a chemical reacti on. The enzyme-substrate complex forms, the reaction occurs, and the products are released. Enzymes lower the activation energy required for the reaction, allowi ng it to proceed more quickly. Factors Affecting Enzyme Activity about:blank 3/4 10/3/24, 9:27 PM Biology unit 3.pdf Temperature: Increased temperature can denature the enzyme, cha nging its shape and rendering it non-functional. pH: Enzymes have an optimal pH range for activity, and deviations c an cause denaturation. Substrate concentration: Increasing substrate concentration increas es the rate of reaction up to a point. Environmental F Effect on Enzyme Activity actor Increased temperature can denature the enzyme, Temperature decreasing activity Enzymes have an optimal pH range for maximum a pH ctivity Substrate Conce Increasing substrate concentration increases react ntration ion rate up to a point about:blank 4/4