Chapter 02 _ Chemistry of Life

Chemistry of Life - Chapter 2 Notes

Page 1

• Chapter Overview

  • Focus on the fundamental chemistry that underpins biological processes.

Page 2

• Learning Objectives (1 of 2)

  • Describe the structure of an atom.

  • Define and discuss the terms:

    • Element

    • Molecule

    • Compound

  • Compare and contrast major types of chemical bonding.

  • Distinguish between organic and inorganic compounds.

  • Discuss the chemical characteristics of water.

  • Discuss acids, bases, and salts.

Page 3

• Learning Objectives (2 of 2)

  • Explain the concept of pH.

  • Discuss the structure and function of organic molecules:

    • Carbohydrates

    • Lipids

    • Proteins

    • Nucleic acids

Page 4

• Levels of Chemical Organization

  • Atom: Smallest unit of matter.

    • Nucleus: Central core of the atom.

      • Proton: Positively charged particle.

      • Neutron: Uncharged particle.

    • Atomic Number: Number of protons.

    • Atomic Mass: Combined number of protons and neutrons.

Page 5

• Atoms

  • Energy Levels: Regions surrounding the nucleus containing electrons.

    • Electron: Negatively charged particle.

    • Each level can hold up to eight electrons.

    • Energy levels increase with distance from the nucleus.

Page 6

• Model of the Atom

  • Visual representation of atomic structure.

Page 7

• Elements, Molecules, and Compounds

  • Element: Pure substance made of one kind of atom.

  • Molecule: Group of atoms bonded together.

  • Compound: Molecules containing more than one kind of atom.

Page 8

• Chemical Bonding

  • Bonds form to stabilize atoms.

  • Atoms react to fill their outermost energy levels.

  • Atoms may share, donate, or borrow electrons.

Page 9-10

• Ionic Bonds

  • Ions: Formed when atoms gain or lose electrons.

    • Positive Ion: Loses electrons (e.g., Na+).

    • Negative Ion: Gains electrons (e.g., Cl−).

  • Ionic bonds form between oppositely charged ions.

  • Electrolyte: Ionic compound that dissociates in water.

Page 12

• Covalent Bonds

  • Formed by sharing outer energy electrons.

  • Generally do not dissociate in water.

  • Essential for forming major organic compounds.

Page 14-15

• Hydrogen Bonds

  • Weak bonds between neighboring molecules.

  • Present in water, DNA, and proteins.

Page 16

• Inorganic Chemistry

  • Organic molecules contain carbon-carbon or carbon-hydrogen bonds; inorganic do not.

  • Organic molecules are typically larger and more complex.

Page 17-18

• Water

  • Essential inorganic compound.

  • Acts as a solvent, forming aqueous solutions.

  • Involved in chemical reactions (e.g., dehydration synthesis, hydrolysis).

  • Energy transfers occur during chemical reactions.

Page 20-22

• Acids, Bases, and Salts

  • Water dissociates into H+ and OH− ions.

  • Acid: Increases H+ concentration.

  • Base: Decreases H+ concentration.

  • pH: Measures H+ concentration; 7 is neutral.

  • Neutralization forms salts; buffers maintain stable pH.

Page 23-24

• Organic Chemistry: Carbohydrates

  • Composed of C, H, and O.

  • Monosaccharides: Basic unit (e.g., glucose).

  • Disaccharides: Two monosaccharides (e.g., sucrose).

  • Polysaccharides: Many monosaccharides (e.g., glycogen).

Page 25-28

• Lipids

  • Triglycerides: Glycerol + three fatty acids; energy storage.

  • Phospholipids: Form cell membranes; have hydrophilic heads and hydrophobic tails.

  • Cholesterol: Stabilizes membranes; precursor for steroid hormones.

Page 29-32

• Proteins

  • Large molecules made of amino acids.

  • Structural Proteins: Form body structures (e.g., collagen, keratin).

  • Functional Proteins: Involved in chemical processes (e.g., enzymes).

  • Enzymes: Catalysts for chemical reactions; operate on a lock-and-key model.

Page 33-36

• Nucleic Acids

  • Composed of nucleotides (phosphate, sugar, nitrogen base).

  • DNA: Master code for protein assembly; double helix structure.

  • RNA: Temporary working copy of DNA; single-stranded.

Page 37

• Adenosine Triphosphate (ATP)

  • Energy currency of the cell.

Page 38

• **Questions?