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?