Chemistry Fundamentals in Anatomy & Physiology

Basic Chemistry Terminology

Understanding chemistry is essential for studying anatomy and physiology, as all biological processes are based on chemical interactions.

• Matter: Anything that occupies space and has mass.

• Elements: Pure substances consisting of only one type of atom (e.g., Oxygen, Carbon).

• Atoms: The smallest units of elements, composed of protons (positive charge), neutrons (neutral), and electrons (negative charge).

• Proton: Positively charged particle in the nucleus of an atom.

• Neutron: Neutral particle in the nucleus.

• Electron: Negatively charged particle orbiting the nucleus.

• Ion: An atom or molecule with a net electric charge due to the loss or gain of electrons.

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

Mixtures and Their Properties

Mixtures are combinations of two or more substances that are not chemically bonded.

• Solutions: Homogeneous mixtures where one substance is dissolved in another (e.g., salt water).

• Colloids: Heterogeneous mixtures with larger particles that do not settle (e.g., cytoplasm).

• Suspensions: Heterogeneous mixtures with large particles that settle out over time (e.g., blood).

Chemical Bonds

Chemical bonds hold atoms together in molecules and compounds.

• Ionic Bonds: Formed when electrons are transferred from one atom to another, creating ions (e.g., NaCl).

• Covalent Bonds: Formed when atoms share electrons (e.g., H2O).

• Hydrogen Bonds: Weak attractions between a hydrogen atom and an electronegative atom (important in DNA and proteins).

Chemical Reactions

Chemical reactions involve the making or breaking of bonds between atoms.

• Types: Synthesis, decomposition, exchange, and reversible reactions.

• Energy: Some reactions release energy (exergonic), others absorb energy (endergonic).

• Reaction Rate: Can be increased by higher temperature, concentration, or the presence of catalysts (enzymes).

Properties of Inorganic Compounds

Water

Water is the most abundant inorganic compound in living organisms and is vital for life.

• Solvent Properties: Dissolves many substances, facilitating chemical reactions.

• High Heat Capacity: Absorbs and releases heat slowly, helping maintain body temperature.

• High Heat of Vaporization: Evaporation of water requires significant energy, aiding in cooling.

• Cushioning: Protects organs by absorbing shock.

Acids, Bases, and Salts

• Acids: Substances that release hydrogen ions (H+) in solution. Example: HCl → H+ + Cl-

• Bases: Substances that release hydroxide ions (OH-) or accept H+. Example: NaOH → Na+ + OH-

• Salts: Ionic compounds formed from acids and bases, dissociating into ions other than H+ or OH-.

pH and Acid/Base Concentration

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

• Acidic: pH < 7

• Basic (Alkaline): pH > 7

• Neutral: pH = 7 (pure water)

Formula:

Properties of Organic Compounds

Monomers, Polymers, and Reactions

• Monomers: Small building blocks (e.g., glucose, amino acids).

• Polymers: Large molecules made from monomers (e.g., starch, proteins).

• Dehydration Synthesis: Joins monomers by removing water.

• Hydrolysis: Breaks polymers into monomers by adding water.

Carbohydrates

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

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

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

• Storage: Animals store carbohydrates as glycogen; plants as starch.

Lipids

• Triglycerides: Neutral fats used for energy storage and insulation.

• Saturated Fats: No double bonds; solid at room temperature.

• Unsaturated Fats: One or more double bonds; liquid at room temperature.

• Phospholipids: Major component of cell membranes; have hydrophilic heads and hydrophobic tails.

• Steroids: Include cholesterol, vitamin D, and hormones.

Proteins (Polypeptides)

• General Characteristics: Made of amino acids; perform structural, enzymatic, and regulatory functions.

• Levels of Organization:

  • Primary: Sequence of amino acids

  • Secondary: Alpha helices and beta sheets

  • Tertiary: 3D folding

  • Quaternary: Multiple polypeptide chains

• Categories:

  • Fibrous: Structural (e.g., collagen)

  • Globular: Functional (e.g., enzymes)

• Enzymes: Biological catalysts that speed up reactions. Three steps: substrate binding, transition state, product release.

Nucleic Acids and ATP

• Nucleic Acids: DNA and RNA; store and transmit genetic information.

• ATP (Adenosine Triphosphate): Main energy currency of the cell; used for cellular work.

Cytology: The Study of Cells

Plasma Membrane

The plasma membrane is a selectively permeable barrier that surrounds the cell, controlling the movement of substances in and out.

• General Functions: Protection, communication, and transport.

• Structure: Phospholipid bilayer with hydrophilic heads facing outward and hydrophobic tails inward.

Membrane Proteins

• Integral Proteins: Span the membrane; involved in transport and signaling.

• Peripheral Proteins: Attached to the membrane surface; involved in support and cell recognition.

Cell Junctions

• Tight Junctions: Seal cells together to prevent leakage.

• Desmosomes: Anchor cells together, providing mechanical strength.

• Gap Junctions: Allow communication between cells via channels.

Membrane Transport

• Passive Transport: Movement of substances without energy input.

  • Simple Diffusion: Movement from high to low concentration.

  • Facilitated Diffusion: Uses carrier or channel proteins.

  • Osmosis: Diffusion of water across a membrane.

• Active Transport: Requires energy (ATP) to move substances against their concentration gradient.

  • Primary Active Transport: Direct use of ATP.

  • Secondary Active Transport: Uses energy from ion gradients.

  • Vesicular Transport: Endocytosis (into cell) and exocytosis (out of cell).

Example: The sodium-potassium pump (Na+/K+ ATPase) is a primary active transport mechanism that maintains cellular ion balance.

Additional info: Some explanations and examples were expanded for clarity and completeness based on standard Anatomy & Physiology curriculum.