Basic Chemistry for Anatomy & Physiology: Study Notes

Basic Chemistry for Anatomy & Physiology

Learning Outcomes

• Define the relationship between matter and energy, and distinguish between potential and kinetic energy.

• Describe the three states of matter and their characteristics.

• Define elements and atoms, and list the four elements that form the bulk of body matter.

• Describe the structure of atoms, including subatomic particles, atomic number, mass number, isotopes, and atomic weight.

• Explain how elements differ from each other and how isotopes of an element differ.

• Define radioisotopes and their medical uses.

• Describe how elements combine to form molecules and compounds.

• Explain the importance of chemical bonds in biological molecules.

• Describe mixtures and how they differ from compounds.

• Discuss the importance of water, salts, acids, and bases in the body.

• Describe the concept of pH and its importance in physiology.

• Describe the major classes of organic molecules: carbohydrates, lipids, proteins, and nucleic acids.

• Describe the structure and function of ATP.

• Describe factors that affect chemical reaction rates.

Matter and Energy

Matter

Matter is anything that has mass and occupies space. All living and non-living things are composed of matter.

• Mass: The amount of matter in an object; remains constant regardless of location.

• Weight: The effect of gravity on mass; can change with location.

States of Matter

Matter exists in three primary states:

• Solid: Definite shape and volume (e.g., bones).

• Liquid: Definite volume, changeable shape (e.g., blood, plasma).

• Gas: Changeable shape and volume (e.g., air in lungs).

Energy

Energy is the capacity to do work or put matter into motion. It does not have mass or occupy space, but it can be measured by its effects on matter.

• Kinetic Energy: Energy in action (e.g., movement of muscles).

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

Energy can be transformed from potential to kinetic energy. Stored energy can be released, resulting in action.

Forms of Energy

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

• Electrical Energy: Results from movement of charged particles (e.g., nerve impulses).

• Mechanical Energy: Directly involved in moving matter (e.g., muscle contraction).

• Radiant (Electromagnetic) Energy: Travels in waves (e.g., light, X-rays).

Energy Transformations

• Energy can be converted from one form to another (e.g., chemical energy from food converted to mechanical energy for movement).

• Some energy is lost as heat during conversions, which contributes to maintaining body temperature.

Atoms and Elements

Elements

An element is a substance that cannot be broken down into simpler substances by ordinary chemical means. Each element is composed of atoms unique to that element.

• Four elements make up about 96% of body weight: Carbon (C), Hydrogen (H), Oxygen (O), and Nitrogen (N).

• Other important elements: Calcium (Ca), Phosphorus (P), Potassium (K), Sulfur (S), Sodium (Na), Chlorine (Cl), Magnesium (Mg), and Iron (Fe).

Atoms

An atom is the smallest unit of an element that retains the properties of that element.

• Atoms are composed of subatomic particles: protons (positive charge), neutrons (no charge), and electrons (negative charge).

Subatomic Particles

Particle	Charge	Location	Mass
Proton	+1	Nucleus	1 atomic mass unit (amu)
Neutron	0	Nucleus	1 amu
Electron	-1	Electron cloud (orbitals)	~0 amu

Atomic Structure

• Nucleus: Central core containing protons and neutrons.

• Electron cloud: Electrons orbit the nucleus in energy levels (shells).

Identifying Elements

• Atomic Number: Number of protons in the nucleus; unique to each element.

• Mass Number: Sum of protons and neutrons in the nucleus.

• Isotopes: Variants of an element with the same number of protons but different numbers of neutrons.

• Atomic Weight: Average of mass numbers of all isotopes of an atom.

Radioisotopes

• Unstable isotopes that decompose to more stable forms, releasing energy (radioactivity).

• Used in medical imaging and cancer treatment.

Atomic Symbols

• One- or two-letter chemical shorthand for each element (e.g., C for carbon, Na for sodium).

• Some symbols come from Latin names (e.g., Na from natrium).

Periodic Table

• Organizes elements by increasing atomic number and similar chemical properties.

• Groups (columns) have similar properties; periods (rows) indicate increasing atomic number.

Summary Table: Key Atomic Terms

Term	Definition
Atomic Number	Number of protons in the nucleus
Mass Number	Number of protons + neutrons
Isotope	Atoms of the same element with different numbers of neutrons
Atomic Weight	Average mass of all isotopes of an element
Radioisotope	Unstable isotope that emits radiation

Additional info:

• Table 2.1 (referenced in the notes) likely lists major elements of the human body and their functions.

• ATP (adenosine triphosphate) is the primary energy carrier in cells; energy is released when ATP is hydrolyzed to ADP.

• Electrons are arranged in shells; the outermost shell (valence shell) determines chemical reactivity.