Fundamental Chemistry Concepts for Anatomy & Physiology

Chemistry Foundations in Anatomy & Physiology

Matter and Its Properties

Matter is anything that occupies space and has mass. Understanding matter is essential for studying the chemical basis of life in anatomy and physiology.

• Mass vs. Weight: Mass is the amount of matter in an object; weight is mass affected by gravity.

• States of Matter:

  • Solids: Definite shape and volume (e.g., bone, teeth)

  • Liquids: Changeable shape, definite volume (e.g., blood plasma, water)

  • Gases: Changeable shape and volume (e.g., respiratory gases such as O2 and CO2)

Energy: Forms and Types

Energy is the capacity to do work or cause change. It is crucial for physiological processes.

• Potential Energy: Stored energy, inactive (e.g., energy stored in chemical bonds)

• Kinetic Energy: Energy in motion, active (e.g., muscle contraction)

• Forms of Energy:

  1. Chemical: Stored in bonds of chemical substances (e.g., ATP)

  2. Electrical: Movement of charged particles (e.g., nerve impulses)

  3. Mechanical: Movement of matter (e.g., muscle movement)

  4. Radiant/Electromagnetic: Energy traveling in waves (e.g., visible light)

Conversion of Energy: Energy can be converted from one form to another, but some is lost as heat.

Elements and Atoms

Elements: Definition and Properties

Elements are pure substances that cannot be broken down by ordinary chemical means. They are the building blocks of matter.

• Physical Properties: Detectable with senses (e.g., color, texture)

• Chemical Properties: How atoms interact (e.g., bonding, reactivity)

• Major Elements in the Human Body: Oxygen, carbon, hydrogen, nitrogen (make up 96% of body mass)

Element	Approx. % of Body Mass	Function
Oxygen	65	Component of water; needed for ATP synthesis
Carbon	18.5	Component of all organic molecules
Hydrogen	9.5	Component of water and most organic molecules
Nitrogen	3.2	Component of proteins and nucleic acids

Structure of Atoms

Atoms are the smallest units of elements, composed of subatomic particles: protons, neutrons, and electrons.

• Protons: Positive charge, mass = 1 amu

• Neutrons: No charge, mass = 1 amu

• Electrons: Negative charge, negligible mass

Protons and neutrons are found in the nucleus; electrons orbit the nucleus.

Atomic Number, Mass Number, and Isotopes

• Atomic Number: Number of protons in the nucleus

• Mass Number: Number of protons plus neutrons

• Isotopes: Atoms of the same element with different numbers of neutrons

Example: Oxygen has atomic number 8 (8 protons), mass number 16 (8 protons + 8 neutrons).

Formula:

$\text{Mass Number} = \text{Number of Protons} + \text{Number of Neutrons}$

Molecules, Compounds, and Mixtures

Molecules and Compounds

Molecules are two or more atoms bonded together. Compounds are molecules composed of two or more different elements.

• Molecule: O2, H2

• Compound: H2O, CO2

Homogeneous vs. Heterogeneous: Homogeneous mixtures are uniform throughout; heterogeneous mixtures are not.

Mixtures: Solutions, Colloids, and Suspensions

Mixtures are combinations of two or more components physically intermixed.

• Solution: Homogeneous mixture (e.g., salt water)

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

• Suspension: Heterogeneous mixture with large particles that settle out (e.g., blood)

Type	Particle Size	Settling	Example
Solution	Small	No	Salt water
Colloid	Intermediate	No	Cytoplasm
Suspension	Large	Yes	Blood

Solute and Solvent

In a solution, the solute is the substance dissolved, and the solvent is the substance doing the dissolving (usually water in biological systems).

Periodic Table and Chemical Properties

Periodic Table Trends

The periodic table organizes elements by increasing atomic number and groups elements with similar chemical properties.

• Physical Properties: Malleability, luster, hardness, conductivity

• Chemical Properties: Reactivity, toxicity, pH

Classification: Organic vs. Inorganic Compounds

Compounds in the body are classified as organic (contain carbon, usually large and complex) or inorganic (do not contain carbon, usually small and simple).

• Organic Compounds: Carbohydrates, lipids, proteins, nucleic acids

• Inorganic Compounds: Water, salts, acids, bases

Summary Table: Key Chemistry Concepts

Concept	Definition	Example/Application
Matter	Anything that occupies space and has mass	Bone, blood, air
Energy	Capacity to do work	ATP, muscle contraction
Atom	Smallest unit of an element	Oxygen atom
Molecule	Two or more atoms bonded	O2, H2O
Compound	Molecule with different elements	CO2, NaCl
Mixture	Physical combination of substances	Blood, cytoplasm

Additional info: These chemistry concepts form the foundation for understanding physiological processes, molecular interactions, and the structure and function of biomolecules in anatomy and physiology.