Fundamental Chemistry Concepts for Anatomy & Physiology

Part A: Matter and Energy in the Universe

Definition and Properties of Matter

Matter is the substance that makes up the universe, and energy is required to move or change matter. Understanding these concepts is foundational for studying biological systems.

• Matter: Anything that occupies space and has mass. The three states of matter are solid, liquid, and gas.

• Energy: The capacity to do work or cause change. Energy exists in various forms, such as chemical energy (stored in bonds) and mechanical energy (movement).

• Conversion: Energy can be converted from one form to another, but some is always lost as heat.

Types of Energy

• Chemical Energy: Stored in chemical bonds; released during reactions.

• Mechanical Energy: Associated with movement, such as muscle contraction.

• Electrical Energy: Movement of charged particles, important in nerve impulses.

Part B: Atomic Structure and Element Properties

Atoms and Subatomic Particles

Atoms are the smallest units of elements, and their structure determines the properties of each element.

• Subatomic Particles: Protons (positive charge), Neutrons (neutral), Electrons (negative charge).

• Nucleus: Contains protons and neutrons; electrons orbit the nucleus.

• Isotopes: Atoms of the same element with different numbers of neutrons.

• Radioisotopes: Unstable isotopes that decay over time, releasing radiation.

Elemental Properties

• Unique Properties: Determined by the number of protons (atomic number).

• Periodic Table: Organizes elements by atomic number and properties.

• Major Elements in the Human Body: Carbon, hydrogen, oxygen, nitrogen (make up >96% of body mass).

Part C: Molecules, Compounds, and Mixtures

Molecules and Compounds

Atoms bond together to form molecules, which can be elements or compounds. Compounds are molecules composed of different elements.

• Molecule: Two or more atoms bonded together.

• Compound: Molecule containing atoms of different elements.

Mixtures

Mixtures are physical combinations of substances. There are three main types:

• Solution: Homogeneous mixture; solute particles are very small and evenly distributed.

• Colloid: Heterogeneous mixture; larger particles that do not settle out.

• Suspension: Heterogeneous mixture; large particles that settle out over time.

Molarity

• Molarity (M): A measure of concentration, defined as moles of solute per liter of solution.

$M = \frac{\text{moles of solute}}{\text{liters of solution}}$

Part D: Chemical Bonds

Types of Chemical Bonds

Chemical bonds hold atoms together in molecules and compounds. The three main types are:

• Ionic Bonds: Formed by the transfer of electrons from one atom to another, resulting in charged ions.

• Covalent Bonds: Formed by the sharing of electrons between atoms. Can be single, double, or triple bonds.

• Hydrogen Bonds: Weak attractions between a hydrogen atom and an electronegative atom (e.g., oxygen or nitrogen).

Bond Strength

• Covalent bonds are the strongest; hydrogen bonds are the weakest.

Octet Rule and Electron Affinity

• Octet Rule: Atoms tend to gain, lose, or share electrons to achieve eight electrons in their outer shell.

• Electron Affinity: Atoms like oxygen are "electron hungry" and have high electronegativity.

Polar vs. Nonpolar Compounds

• Polar Compounds: Unequal sharing of electrons, resulting in partial charges (e.g., water).

• Nonpolar Compounds: Equal sharing of electrons; no charge separation (e.g., oxygen gas).

Part E: Chemical Reactions

Types of Chemical Reactions

Chemical reactions involve the making and breaking of bonds, leading to new substances.

• Synthesis: Two or more reactants combine to form a larger product.

• Decomposition: A compound breaks down into smaller components.

• Exchange: Bonds are both made and broken; atoms are exchanged between molecules.

Oxidation-Reduction (Redox) Reactions

• Oxidation: Loss of electrons.

• Reduction: Gain of electrons.

Reaction Rate Factors

• Temperature

• Concentration of reactants

• Particle size

• Presence of catalysts

Part F: Inorganic Compounds

Water, Salts, Acids, and Bases

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

• Water: Most important inorganic compound; universal solvent.

• Salts: Ionic compounds that dissociate into ions in water; important for nerve and muscle function.

• Electrolytes: Substances that conduct electricity when dissolved in water (e.g., Na+, K+).

• Acids: Proton donors; release H+ ions (e.g., HCl).

• Bases: Proton acceptors; release OH- ions (e.g., NaOH).

pH Scale

• Measures hydrogen ion concentration; ranges from 0 (acidic) to 14 (basic), with 7 as neutral.

Buffers

• Substances that stabilize pH by absorbing or releasing H+ ions.

Part G: Organic Molecules and Macromolecules

Organic vs. Inorganic Molecules

Organic molecules contain carbon and are unique to living systems. Macromolecules are large, complex organic molecules.

• Organic Molecules: Contain carbon; include carbohydrates, lipids, proteins, nucleic acids.

• Macromolecules: Large molecules formed by joining smaller units (monomers).

Synthesis and Hydrolysis

• Dehydration Synthesis: Monomers are joined by removing water.

• Hydrolysis: Macromolecules are broken down by adding water.

Part H: Carbohydrates, Lipids, Proteins, and Nucleic Acids

Carbohydrates

Carbohydrates are sugars and starches that provide energy.

• Monosaccharides: Simple sugars (e.g., glucose).

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

• Polysaccharides: Long chains of monosaccharides (e.g., starch, glycogen).

• Ratio: Carbon:Hydrogen:Oxygen is typically 1:2:1.

Lipids

• Triglycerides: Yield large amounts of energy when oxidized.

• Saturated vs. Unsaturated Fats: Saturated fats have no double bonds; unsaturated fats have one or more double bonds.

• Trans Fats: Artificially altered fats; associated with health risks.

• Phospholipids: Chief component of cell membranes.

• Steroids: Built from four-ring structures (e.g., cholesterol).

Proteins

• Amino Acids: Monomers used to build proteins.

• Functions: Structural support, enzymes, transport, movement, regulation, immune defense.

Levels of Protein Structure

• Primary: Sequence of amino acids.

• Secondary: Alpha helices and beta sheets formed by hydrogen bonding.

• Tertiary: 3D folding due to side chain interactions.

• Quaternary: Association of multiple polypeptide chains.

Enzymes and Catalysis

• Catalyst: Substance that speeds up a chemical reaction without being consumed.

• Activation Energy: Energy required to start a reaction.

$\text{Enzyme Reaction Steps:}$ 1. Substrate binds to enzyme 2. Enzyme-substrate complex forms 3. Products are released

Nucleic Acids

• DNA and RNA: Store and transmit genetic information.

• Nucleotide: Common building block for DNA and RNA.

• ATP: Adenosine triphosphate; main energy carrier in cells.

$\text{ATP} \rightarrow \text{ADP} + \text{P}_i + \text{energy}$

Additional info: These chemistry concepts are foundational for understanding physiological processes such as metabolism, cellular structure, and molecular interactions in Anatomy & Physiology.