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Basic Chemistry

2.1 What is Matter?

Matter is anything that occupies space and has mass. It exists in three primary states: solid, liquid, and gas.

  • States of Matter: Solid, liquid, gas

Energy is the capacity to do work or cause change. It exists in various forms and can be converted from one form to another, but cannot be created or destroyed (law of conservation of energy).

  • Kinetic Energy: Energy of motion

  • Potential Energy: Stored energy

  • Forms of Energy:

    • Chemical: Stored in bonds

    • Electrical: Movement of charged particles

    • Mechanical: Movement of objects

    • Radiant: Waves (e.g., light)

2.2 What is Matter Composed Of?

All matter is composed of elements, which are substances that cannot be broken down into simpler substances by ordinary chemical means.

  • Elements: 118 known, 91 naturally occurring

  • Major Elements in the Human Body: Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N) – make up 96% of body weight

  • Atoms: Smallest unit of an element, composed of:

    • Protons: Positively charged

    • Neutrons: No charge

    • Electrons: Negatively charged

  • Atomic Structure: Planetary model (nucleus with protons and neutrons, electrons in orbitals)

Unique Properties of Elements:

  • Atomic number (number of protons)

  • Mass number (protons + neutrons)

  • Isotopes (atoms with same number of protons but different neutrons)

  • Radioisotopes (unstable isotopes that emit radiation)

  • Periodic table organizes elements by properties

2.3 How is Matter Combined into Molecules and Mixtures?

  • Molecules: Two or more atoms bonded together

  • Compounds: Molecules with different types of atoms

  • Mixtures: Physical combinations of substances

    • Solutions: Homogeneous mixtures (solute dissolved in solvent)

      • Concentration measured in percent, mg/dL, or molarity

    • Colloids: Heterogeneous mixtures with larger particles (e.g., cytosol)

    • Suspensions: Large particles that settle out (e.g., blood)

2.4 What are the Three Kinds of Chemical Bonds?

  • Ionic Bonds: Transfer of electrons from one atom to another, forming ions (cations and anions)

  • Covalent Bonds: Sharing of electrons between atoms

    • Single, double, or triple bonds

    • Polar (unequal sharing) or nonpolar (equal sharing)

  • Hydrogen Bonds: Weak attractions between polar molecules

2.5 How Do Chemical Reactions Form, Rearrange, or Break Bonds?

  • Chemical Equations: Represent chemical reactions

  • Types of Chemical Reactions:

    • Synthesis (Anabolic): Building larger molecules

    • Decomposition (Catabolic): Breaking down molecules

    • Exchange: Both synthesis and decomposition

    • Redox (Oxidation-Reduction): Transfer of electrons

  • Example: Cellular respiration:

  • Energy Flow: Chemical reactions can release (exergonic) or absorb (endergonic) energy

  • Factors Influencing Reaction Rates:

    • Concentration of reactants

    • Particle size

    • Temperature

    • Catalysts (e.g., enzymes)

Biochemistry

2.6 Importance of Inorganic Compounds in the Body

Inorganic compounds such as water, salts, acids, and bases are essential for life.

  • Water: High heat capacity, high heat of vaporization, universal solvent, reactivity (hydrolysis, dehydration synthesis), cushioning

  • Salts: Dissociate into ions in water, form electrolytes that conduct electricity

  • Acids: Proton donors, release H+ in solution

  • Bases: Proton acceptors, release OH- in solution

pH Scale: Measures hydrogen ion concentration

  • pH = -log[H+]

  • Scale: 0 (acidic) to 14 (basic), 7 is neutral

  • Buffers help maintain pH homeostasis

2.7 Organic Compounds: Structure and Breakdown

Organic compounds contain carbon and are the basis of all living things. They are often large macromolecules formed by dehydration synthesis and broken down by hydrolysis.

  • Dehydration Synthesis: Joins monomers by removing water

  • Hydrolysis: Breaks polymers by adding water

2.8 Four Classes of Organic Compounds in Living Systems

Class

Monomer

Function

Carbohydrates

Monosaccharides (glucose, fructose)

Energy source, structure

Lipids

Fatty acids, glycerol

Energy storage, insulation, cell membranes

Proteins

Amino acids

Structure, enzymes, transport, regulation

Nucleic Acids

Nucleotides

Genetic information, protein synthesis

Carbohydrates

  • Monosaccharides: Simple sugars (glucose, galactose, fructose)

  • Disaccharides: Two monosaccharides joined (sucrose, lactose, maltose)

  • Polysaccharides: Many monosaccharides (starch, glycogen)

Lipids

  • Triglycerides: Glycerol + 3 fatty acids (energy storage)

  • Phospholipids: Glycerol + 2 fatty acids + phosphate (cell membranes)

  • Steroids: Four fused rings (cholesterol, hormones)

Proteins

  • Polymers of amino acids (20 types)

  • Levels of Structure:

    • Primary: Linear sequence of amino acids

    • Secondary: Alpha helix or beta sheet (hydrogen bonds)

    • Tertiary: 3D folding (hydrophobic/hydrophilic interactions, disulfide bridges)

    • Quaternary: Multiple polypeptide chains

  • Denaturation: Loss of structure and function due to environmental changes

  • Functions: Enzymes, structure, transport, regulation

Nucleic Acids

  • DNA: Deoxyribonucleic acid, stores genetic information

  • RNA: Ribonucleic acid, involved in protein synthesis

  • Nucleotides: Composed of a sugar, phosphate group, and nitrogenous base (adenine, guanine, cytosine, thymine for DNA; uracil replaces thymine in RNA)

  • ATP: Adenosine triphosphate, main energy currency of the cell

Example: ATP hydrolysis releases energy for cellular processes:

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