Foundations of Chemistry and Cell Biology for Anatomy & Physiology

Chemistry Fundamentals for Anatomy & Physiology

Basic Chemistry Terminology

Chemistry provides the foundation for understanding biological processes in Anatomy & Physiology. Key terms and concepts are essential for describing matter and its interactions.

• Matter: Anything that has mass and occupies space. Examples include solids, liquids, and gases.

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

• Atoms: The smallest units of elements, composed of protons, neutrons, and electrons.

• Proton: Positively charged particle in the nucleus.

• Neutron: Neutral particle in the nucleus.

• Electron: Negatively charged particle orbiting the nucleus.

• Ion: Atom or molecule with a net electric charge due to 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 retain their individual properties.

• Solutions: Homogeneous mixtures where solutes are dissolved in solvents (e.g., salt water).

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

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

Chemical Bonds

Chemical bonds hold atoms together in molecules and compounds.

• Ionic Bonds: Formed by the transfer of electrons from one atom to another, resulting in oppositely charged ions (e.g., NaCl).

• Covalent Bonds: Formed by the sharing of electrons between atoms (e.g., H2O).

• Hydrogen Bonds: Weak attractions between polar molecules, important in water and DNA structure.

Chemical Reactions

Chemical reactions involve the making and breaking of bonds, resulting in new substances.

• Types of Reactions: Synthesis, decomposition, exchange.

• Energy Release: Exergonic reactions release energy; endergonic reactions absorb energy.

• Rate of Reaction: Influenced by temperature, concentration, particle size, and catalysts.

Properties of Inorganic Compounds

Inorganic compounds are essential for physiological processes.

• Water: Universal solvent, high heat capacity, high heat of vaporization, cushioning agent.

• Acids: Release H+ ions in solution. $\text{Acid} \rightarrow \text{H}^+ + \text{anion}$

• Bases: Release OH- ions in solution. $\text{Base} \rightarrow \text{OH}^- + \text{cation}$

• Salts: Ionic compounds that dissociate into ions other than H+ or OH-.

• pH Scale: Measures acidity or alkalinity. $\text{pH} = -\log_{10}[\text{H}^+]$

• Acidic: pH < 7; Neutral: pH = 7; Basic: pH > 7

Organic Compounds in Physiology

Monomers, Polymers, and Reactions

Organic compounds are built from monomers joined to form polymers via dehydration synthesis; hydrolysis breaks them down.

• Monomer: Single subunit (e.g., glucose).

• Polymer: Chain of monomers (e.g., starch).

• Dehydration Synthesis: Removal of water to join monomers.

• Hydrolysis: Addition of water to break polymers into monomers.

Carbohydrates

Carbohydrates are energy sources and structural components.

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

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

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

• Formation/Breakdown: Formed by dehydration synthesis; broken down by hydrolysis.

Lipids

Lipids are hydrophobic molecules important for energy storage and membrane structure.

• Triglycerides: Neutral fats; composed of glycerol and three fatty acids.

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

• Phospholipids: Have polar heads and nonpolar tails; form the plasma membrane.

• Steroids: Four-ring structure; includes cholesterol, vitamin D, hormones.

Proteins (Polypeptides)

Proteins perform diverse functions and have complex structures.

• General Characteristics: Made of amino acids; function depends on structure.

• Levels of Organization:

  • Primary: Sequence of amino acids.

  • Secondary: Alpha helices and beta sheets.

  • Tertiary: 3D folding.

  • Quaternary: Multiple polypeptide chains.

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

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

• Enzymes: Biological catalysts; lower activation energy. Three steps: substrate binding, transition state, product release.

Nucleic Acids

Nucleic acids store and transmit genetic information.

• DNA: Double helix; stores genetic code.

• RNA: Single-stranded; involved in protein synthesis.

• ATP: Adenosine triphosphate; main energy currency of the cell.

• ATP Function: Provides energy for cellular processes.

Cell Biology (Cytology)

Plasma Membrane

The plasma membrane is a selectively permeable barrier that regulates the movement of substances into and out of the cell.

• General Functions: Protection, communication, transport, cell recognition.

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

Membrane Proteins

Proteins within the plasma membrane serve various roles.

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

• Peripheral Proteins: Attached to the surface; involved in signaling.

Cell Junctions

Cell junctions connect cells and facilitate communication.

• Tight Junctions: Prevent leakage between cells.

• Desmosomes: Provide mechanical strength.

• Gap Junctions: Allow passage of ions and small molecules.

Membrane Transport

Transport across the plasma membrane is essential for homeostasis.

• Passive Transport: No energy required.

  • Simple Diffusion: Movement of molecules from high to low concentration.

  • Facilitated Diffusion: Uses carrier or channel proteins.

  • Osmosis: Diffusion of water across a membrane.

• Active Transport: Requires energy (ATP).

  • Primary Active Transport: Direct use of ATP (e.g., Na+/K+ pump).

  • Secondary Active Transport: Uses energy from ion gradients.

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

Table: Comparison of Membrane Transport Mechanisms

Transport Type	Energy Required	Example
Simple Diffusion	No	O2 movement
Facilitated Diffusion	No	Glucose transport
Osmosis	No	Water movement
Primary Active Transport	Yes (ATP)	Na+/K+ pump
Secondary Active Transport	Yes (ion gradient)	Glucose-Na+ co-transport
Vesicular Transport	Yes (ATP)	Endocytosis, exocytosis

Additional info: Academic context and definitions have been expanded for clarity and completeness. Table entries inferred for completeness.