Fundamental Chemistry Concepts for Anatomy & Physiology

Introduction to Chemistry in Anatomy & Physiology

Chemistry forms the foundation for understanding biological processes in Anatomy & Physiology. This section covers essential chemical principles, including the structure of matter, atomic theory, chemical bonding, and the major classes of biomolecules.

Basic Concepts of Matter and Elements

• Matter: Anything that has mass and occupies space. The smallest unit of matter is the atom.

• Element: A pure substance consisting of only one type of atom, defined by its number of protons. Examples include hydrogen (H), carbon (C), oxygen (O), nitrogen (N), calcium (Ca), sodium (Na), and potassium (K).

• Major Elements in the Human Body: The most common elements by mass are oxygen, carbon, hydrogen, and nitrogen.

Atomic Structure

• Atom: Composed of three subatomic particles:

  • Protons: Positively charged, located in the nucleus.

  • Neutrons: No charge, located in the nucleus.

  • Electrons: Negatively charged, orbit the nucleus.

• Atomic Number: Number of protons in the nucleus; defines the element.

• Atomic Mass: Sum of protons and neutrons.

• Charge: Atoms are neutral when protons = electrons; ions form when this balance is disrupted.

Ions and Isotopes

• 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.

Types of Bonds and Molecules

• Ionic Bond: Formed when electrons are transferred from one atom to another, creating oppositely charged ions.

• Covalent Bond: Formed when two atoms share one or more pairs of electrons.

• Molecule: Two or more atoms held together by covalent bonds.

• Compound: A substance formed from two or more different elements chemically bonded together.

• Organic Compound: Contains carbon and hydrogen, often found in living organisms (e.g., glucose).

• Inorganic Compound: Generally does not contain both carbon and hydrogen (e.g., water, salts).

Solutions, Solvents, and Solutes

• Solution: A homogeneous mixture of two or more substances.

• Solvent: The substance present in the greatest amount; dissolves the solute (e.g., water in the human body).

• Solute: The substance dissolved in the solvent.

• Concentration: The amount of solute in a given volume of solution.

Chemical Reactions and Bonds

• Chemical Bond: The force that holds atoms together in a molecule or compound.

• Chemical Reaction: The process by which chemical bonds are formed, rearranged, or broken.

• Types of Chemical Bonds: Ionic, covalent, and hydrogen bonds.

• Acid: Substance that releases hydrogen ions (H+) in solution.

• Base: Substance that accepts hydrogen ions or releases hydroxide ions (OH-).

• Salt: Compound formed from the reaction of an acid and a base.

pH and Buffers

• pH: A measure of hydrogen ion concentration; scale ranges from 0 (acidic) to 14 (basic), with 7 being neutral.

• Buffer: A substance that minimizes changes in pH by accepting or donating H+ ions.

Biomolecules: Carbohydrates, Lipids, and Proteins

Biomolecules are essential for structure and function in living organisms. The major classes include carbohydrates, lipids, and proteins.

Carbohydrates

• Definition: Organic molecules composed of carbon, hydrogen, and oxygen, typically in a 1:2:1 ratio.

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

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

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

• Functions: Provide energy, store energy, and serve as structural components.

• Storage: Glycogen is the main storage form in animals; starch in plants.

Lipids

• Definition: Hydrophobic organic molecules, including fats, oils, phospholipids, and steroids.

• Triglycerides: Composed of glycerol and three fatty acids; main form of stored energy in animals.

• Phospholipids: Major component of cell membranes; consist of glycerol, two fatty acids, and a phosphate group.

• Steroids: Lipids with a four-ring structure; examples include cholesterol and hormones.

• Functions: Energy storage, insulation, cell membrane structure, and hormone production.

Proteins

• Definition: Polymers of amino acids linked by peptide bonds.

• Amino Acids: Building blocks of proteins; 20 different types in humans.

• Structure: Proteins have four levels of structure:

  • Primary: Sequence of amino acids.

  • Secondary: Local folding (e.g., alpha-helix, beta-sheet).

  • Tertiary: Three-dimensional shape.

  • Quaternary: Association of multiple polypeptide chains.

• Functions: Enzymes, structural support, transport, signaling, and immune response.

ATP (Adenosine Triphosphate)

• Definition: The primary energy carrier in cells.

• Function: Stores and transfers energy for cellular processes.

• Structure: Composed of adenine, ribose, and three phosphate groups.

• Energy Release: Energy is released when ATP is hydrolyzed to ADP (adenosine diphosphate) and inorganic phosphate: $ATP \rightarrow ADP + P_i + \text{energy}$

Summary Table: Major Biomolecules

Biomolecule	Monomer	Main Functions	Examples
Carbohydrates	Monosaccharides	Energy source, storage, structure	Glucose, starch, glycogen
Lipids	Fatty acids, glycerol	Energy storage, membranes, hormones	Triglycerides, phospholipids, cholesterol
Proteins	Amino acids	Enzymes, structure, transport, signaling	Hemoglobin, enzymes, antibodies

Additional info:

• Students should also review laboratory material corresponding to this chapter for a comprehensive understanding.