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The Chemistry of Life: Matter, Compounds, and Enzymes

This chapter explores the nature of matter, atoms, compounds, and enzymes in the chemistry of life. Topics include the structure of atoms, different types of bonds, mixtures and solutions, pH, properties of water, carbon compounds, and chemical reactions.

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The Chemistry of Life: Matter, Compounds, and Enzymes

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  1. Chapter 2 The Chemistry of Life

  2. 2.1 The nature of matter • Atom: the smallest particle of an element that has the properties of that element • Atom is made of three subatomic particles: • Proton * Positive, nucleus • Electron * Negative, outside nucleus in energy levels • First energy level -- 2e • Second energy level -- 8e • Third energy level -- 18e • Neutron * No charge, nucleus

  3. Number of protons usually is equal to the number of electrons so that the overall charge of an atom is neutral!! • If atoms of the same element have different number of neutrons, they are called isotopes! EX. C - 12 , C - 13, C - 14 • When two or more atoms of different elements are chemically combined you create what is called a compound. EX. Water

  4. Compounds can be made with three different kinds of bonds: • Covalent • Share electrons to be stable • Strongest and most common bond • Molecule: group of atoms held together with covalent bonds with no overall charge • Van der Waals forces (what holds molecules together)

  5. Ionic • Gain / lose electrons to be stable • Ion: a charged particle • Less abundant in living things than covalent bonds • Hydrogen

  6. Mixtures & Solutions • Mixture: a combination of substances in which the individual components retain their own properties • Solution: a mixture in which one or more substances are distributed evenly in another substance • Two parts to every solution: • Solute --- What is being dissolved • Solvent -- What is doing the dissolving * Most common... WATER

  7. pH • pH: a measure of how acidic or basic a solution is • Acid: substance that forms H+ ions in water • 0 - 7 • Base: substance that forms OH- ions in water • 7 – 14

  8. Acids & Bases Acids Bases Lower concentration of H+ ions pH value more than 7 Bitter taste Slippery Turn red litmus paper blue if an object is a base • Higher concentration of H+ ions • pH value less than 7 • Sour taste • React with metals • Blue litmus paper will turn red if an object is an acid

  9. 2.2 Water and Diffusion • Perhaps the most important compound in living organisms is water! • Properties of water: • Polarity • Has a positive and negative end • Gives water its dissolving property • Resists Temperature Changes • Water expands when it freezes • Adhesion  Graduated cylinder • Adhesion is greater between glass & water than water & water!

  10. 2.3 Carbon Compounds • The one element that defines living organisms is Carbon! • Carbon has four electrons in its outermost shell; therefore, it can combine with almost every other element • Any compound that contains carbon is considered to be an organic compound! • If it does not contain carbon it is inorganic.

  11. Four types of Organic compounds: • Carbohydrates: • Made of C, H, O (C to H ration is 2 to 1) • Monomer: monosaccharide • Function: Provide quick energy • EX. Glucose: how animals store food Starch: how plants store food Cellulose: composes cell walls of plants

  12. 2) Lipids • Made of C, H, O --- (C to H ratio higher than 2 to 1) • Monomer: Glycerol & 3 fatty acids • Function: 1) Store energy 2) Insulation 3) Protection • EX. Fats and Oils

  13. 3) Proteins • Made of C, H, O, N, Sulfur • Monomer: Amino Acid • 20 AA • Function: 1) Build Muscle 2)Transportation (blood -- hemoglobin) 3) Speed up chemical reactions (enzymes)

  14. 4) Nucleic Acids • Made of C, H, O, N, Phosphorus • Monomer: Nucleotide • Function: Store genetic information • EX. DNA (Deoxyribose Nucleic Acid) – Master RNA (Ribose Nucleic Acid) -- Copy of DNA

  15. 2.4 Chemical Reactions and Enzymes • Chemical reaction = changes one set of chemicals into another set of chemicals • Chemical reactions have two parts: • Reactants • Products • CO2 + H2O  H2CO3 Reactants Product

  16. Enzymes • Enzymes are proteins that act as a biological catalyst. • Catalyst: a substance that speeds up the rate of chemical reaction • Enzymes speed up chemical reactions that take place in the cell.

  17. Enzyme Action • The enzyme-substrate complex • Enzymes are substrate specific. • They act like a lock and key. • Enzymes will only catalyze their substrates. • Regulation of Enzyme Activity • Enzymes can be affected by: • Heat • pH • Concentration of Substrate • Proteins that turn enzymes “on” and “off”

  18. Example of what an enzyme does! How enzymes work Potato + Peroxide  water + oxygen (catalase)

  19. Where are enzymes? • Enzymes regulate many chemical reactions such as: • Photosynthesis • Cellular respiration • Digestion • Enzymes are reusable • Once they work with one substrate they release and go to another substrate.

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