Chemical Foundations of Anatomy & Physiology

Subatomic Particles and Atomic Structure

Understanding the basic structure of atoms is essential for grasping how elements interact in the human body.

• Subatomic Particles: Atoms are composed of protons (positively charged), neutrons (neutral), and electrons (negatively charged).

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

• Example: Hydrogen has 1 proton and 1 electron; carbon has 6 protons, 6 neutrons, and 6 electrons.

Isotopes

Isotopes are variants of elements with the same number of protons but different numbers of neutrons.

• Definition: Isotopes have identical atomic numbers but different mass numbers.

• Example: Carbon-12 and Carbon-14 are isotopes of carbon.

Elements in the Human Body

The human body is primarily composed of a few key elements.

• Most Abundant Elements: Oxygen, Carbon, Hydrogen, Nitrogen.

• Trace Elements: Elements required in small amounts, such as iron, iodine, and zinc, are vital for physiological processes.

• Examples: Iron is essential for hemoglobin; iodine is needed for thyroid hormones.

Ions and Chemical Bonds

Atoms interact through the transfer or sharing of electrons, forming ions and chemical bonds.

• Cation: An ion with a positive charge (e.g., Na+).

• Anion: An ion with a negative charge (e.g., Cl-).

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

• Covalent Bonds: Formed by the sharing of electron pairs between atoms.

• Comparison Table:

Polar and Nonpolar Molecules

Molecules can be classified based on the distribution of electrical charge.

• Polar Molecules: Have regions of partial positive and negative charge due to unequal sharing of electrons (e.g., water).

• Nonpolar Molecules: Have an even distribution of charge (e.g., oxygen gas).

Hydrogen Bonds and Water Properties

Hydrogen bonds are weak attractions between polar molecules, crucial for water's unique properties.

• Hydrogen Bond: Attraction between a hydrogen atom (attached to O or N) and another electronegative atom.

• Properties of Water:

Chemical Reactions and Enzymes

Activation Energy and Enzymes

Chemical reactions require energy to proceed, known as activation energy. Enzymes are biological catalysts that lower activation energy, speeding up reactions.

• Activation Energy (): The minimum energy required for a reaction to occur.

• Enzyme Function: Enzymes bind substrates and facilitate their conversion to products.

pH and Buffers

pH measures the concentration of hydrogen ions in a solution, indicating its acidity or alkalinity.

• pH Scale: Ranges from 0 (acidic) to 14 (basic); 7 is neutral.

• Formula:

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

Organic Macromolecules

Types and Functions

Four major classes of organic macromolecules are essential for life.

• Carbohydrates: Provide energy and structural support (e.g., glucose, starch).

• Lipids: Store energy, form cell membranes (e.g., triglycerides, phospholipids).

• Proteins: Perform a wide range of functions, including catalysis (enzymes), transport, and structure (e.g., hemoglobin, collagen).

• Nucleic Acids: Store and transmit genetic information (e.g., DNA, RNA).

Enzyme Structure and Function

Enzymes are proteins with specific three-dimensional structures that determine their function.

• Structure: Made of amino acids folded into a unique shape; active site binds substrates.

• Function: Catalyze biochemical reactions by lowering activation energy.

• Example: Amylase breaks down starch into sugars.

Key Tables and Diagrams

Elemental Composition Table

pH Scale Diagram

• Acidic: pH < 7 (e.g., stomach acid)

• Neutral: pH = 7 (e.g., pure water)

• Basic: pH > 7 (e.g., blood)

Organic Compound Classification

Summary

• Atoms and molecules form the basis of all matter in the body.

• Chemical bonds and interactions determine the structure and function of biological molecules.

• Water's properties, pH, and buffers are critical for maintaining homeostasis.

• Organic macromolecules perform essential roles in energy, structure, and information storage.

Additional info: Some explanations and examples have been expanded for clarity and completeness.