Chemical Foundations of Anatomy & Physiology

Elements and Atoms

Understanding the basic building blocks of matter is essential for studying Anatomy & Physiology. Elements and atoms form the foundation of all biological molecules.

• Element: A pure substance consisting of only one type of atom. Elements cannot be broken down into simpler substances by chemical means.

• Most Common Elements in the Human Body: Oxygen (O), Carbon (C), Hydrogen (H), Nitrogen (N).

• Atom: The smallest unit of an element that retains its chemical properties. Atoms consist of a nucleus (protons and neutrons) and electrons orbiting the nucleus.

• Relationship: Elements are defined by the type of atoms they contain. Each element has atoms with a specific number of protons.

Atomic Structure

Atoms are composed of subatomic particles, each with distinct properties.

• Proton: Positively charged particle located in the nucleus.

• Neutron: Neutral particle located in the nucleus.

• Electron: Negatively charged particle orbiting the nucleus.

• Charge and Location: Protons and neutrons are found in the nucleus; electrons are found in energy levels around the nucleus.

Ions and Chemical Species

Chemical reactions often involve the transfer or sharing of electrons, resulting in the formation of ions.

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

• Anion: A negatively charged ion (gains electrons).

• Cation: A positively charged ion (loses electrons).

Organic vs. Inorganic Molecules

Molecules in living organisms are classified as organic or inorganic based on their composition.

• Organic Molecules: Contain carbon and hydrogen, often found in living organisms (e.g., carbohydrates, proteins, lipids, nucleic acids).

• Inorganic Molecules: Do not contain both carbon and hydrogen (e.g., water, salts, acids, bases).

Properties and Importance of Water

Water is vital for life due to its unique chemical properties.

• Polarity: Water molecules have a partial positive and negative end, allowing them to form hydrogen bonds.

• Universal Solvent: Water dissolves many substances, facilitating chemical reactions.

• High Heat Capacity: Water absorbs and retains heat, helping regulate body temperature.

• Importance: Water is essential for transport, temperature regulation, and chemical reactions in the body.

Acids, Bases, and pH

Acids and bases are important for maintaining homeostasis in the body.

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

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

• Comparison: Acids have higher H+ concentration; bases have higher OH- concentration.

pH Scale

The pH scale measures the concentration of hydrogen ions in a solution.

• Scale: Ranges from 0 (most acidic) to 14 (most basic).

• Neutral Solution: pH = 7 (equal H+ and OH-).

• Acidic Solution: pH < 7 (higher H+).

• Basic Solution: pH > 7 (higher OH-).

Equation:

Buffers

Buffers help maintain stable pH in the body by neutralizing excess acids or bases.

• Significance: Buffers prevent drastic changes in pH, which could disrupt cellular processes.

Salts and Electrolytes

Salts are ionic compounds that dissociate in water to form electrolytes, which are essential for physiological functions.

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

• Electrolyte: Substance that conducts electricity when dissolved in water (e.g., sodium, potassium, calcium ions).

• Examples: Sodium chloride (NaCl), potassium chloride (KCl), calcium phosphate (Ca3(PO4)2).

Biomolecules in Living Organisms

Organic molecules are classified into four major types, each with specific functions in the body.

• Carbohydrates

• Lipids

• Proteins

• Nucleic Acids

Monomers and Polymers

Biomolecules are often formed by linking smaller units (monomers) into larger chains (polymers).

• Monomer: Small, repeating unit that forms polymers (e.g., glucose, amino acid, nucleotide).

• Polymer: Large molecule made of many monomers (e.g., starch, protein, DNA).

Carbohydrates: Structure and Function

Carbohydrates are classified by the number of sugar units they contain.

• Monosaccharides: Single sugar units (e.g., glucose, fructose, galactose, ribose, deoxyribose).

• Disaccharides: Two sugar units (e.g., sucrose, lactose, maltose).

• Polysaccharides: Many sugar units (e.g., glycogen, cellulose, starch).

• Function: Provide energy and structural support.

Lipids: Structure and Function

Lipids are diverse molecules with roles in energy storage, membrane structure, and signaling.

• Triglycerides: Composed of glycerol and three fatty acids; main energy storage form.

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

• Steroids: Four fused carbon rings; include hormones like cholesterol.

Proteins: Structure and Function

Proteins are polymers of amino acids and perform a wide variety of functions in the body.

• Amino Acid: Building block of proteins; contains an amino group, carboxyl group, and side chain.

• Functions: Structural support, transport, enzymes (catalysts), defense, movement.

• Example: Hemoglobin (oxygen transport), collagen (structural support).

Nucleic Acids: DNA and RNA

Nucleic acids store and transmit genetic information.

• DNA (Deoxyribonucleic Acid): Double-stranded, found in the nucleus, stores genetic information.

• RNA (Ribonucleic Acid): Single-stranded, found in the nucleus and cytoplasm, involved in protein synthesis.

• Monomer: Nucleotide (composed of a sugar, phosphate, and nitrogenous base).

ATP: Cellular Energy

Adenosine triphosphate (ATP) is the primary energy carrier in cells.

• ATP Function: Provides energy for cellular work by releasing a phosphate group.

• Reaction: ATP is synthesized from ADP and inorganic phosphate; breakdown releases energy.

Equation:

Additional info: ATP is regenerated in cells through cellular respiration, ensuring a constant supply of energy for metabolic processes.