Basic Chemistry for Anatomy & Physiology: Foundations of Matter, Energy, and Chemical Bonds

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Basic Chemistry for Anatomy & Physiology

Introduction

This study guide covers foundational chemistry concepts essential for understanding Anatomy & Physiology. Topics include matter and energy, atomic structure, chemical bonds, mixtures and compounds, and the role of electrons in chemical reactions.

Matter and Energy

Definitions and Properties

Matter: Anything that has mass and occupies space. Matter can be seen, smelled, and felt.
Energy: The capacity to do work or put matter into motion. Energy does not take up space or have mass.
Weight: Mass plus the effects of gravity.

States of Matter

Solid: Definite shape and volume.
Liquid: Definite volume, changeable shape.
Gas: Changeable shape and volume.

Types of Energy

Kinetic Energy: Energy in action (e.g., movement).
Potential Energy: Stored energy (e.g., chemical bonds, ATP).
Energy can be transformed from potential to kinetic and vice versa.
Energy conversions are inefficient; some energy is lost as heat.

Forms of Energy

Chemical Energy: Stored in bonds of chemical substances.
Electrical Energy: Results from movement of charged particles (ions, electrolytes).
Mechanical Energy: Directly involved in moving matter.
Radiant/Electromagnetic Energy: Travels in waves (e.g., heat, visible light, UV light, X-rays).

Atoms and Elements

Elements

Element: A substance that cannot be broken down into simpler substances by ordinary chemical means.
There are 118 known elements; 92 occur naturally.
Four elements make up 96% of the body: Carbon, oxygen, hydrogen, nitrogen.
Other elements (calcium, phosphorus, potassium, etc.) are present in smaller amounts.

Atoms

Atom: The smallest unit of an element that retains its properties.
Atoms are made up of subatomic particles: protons, neutrons, and electrons.
Protons: Positive charge, mass = 1 amu.
Neutrons: No charge, mass = 1 amu.
Electrons: Negative charge, virtually no mass (0 amu).
Protons and neutrons are located in the nucleus; electrons orbit around the nucleus.

Atomic Number, Mass Number, and Isotopes

Atomic Number: Number of protons in the nucleus (also equals the number of electrons in a neutral atom).
Mass Number: Total number of protons and neutrons in the nucleus.
Isotopes: Atoms of the same element with different numbers of neutrons (different mass numbers).
Atomic Weight: Average of mass numbers of all isotope forms of an atom.
Radioisotopes: Unstable isotopes that decompose, releasing energy (radioactivity). Used in medical imaging (e.g., PET scans) and cancer treatment.

Atomic Symbols

One- or two-letter abbreviations for each element (e.g., O for oxygen, C for carbon).
Some symbols are derived from Latin names (e.g., Na for sodium, K for potassium).

Combining Matter: Molecules, Compounds, and Mixtures

Molecules and Compounds

Molecule: Two or more atoms bonded together (e.g., O2).
Compound: Molecule with two or more different kinds of atoms bonded together (e.g., H2O, C6H12O6).

Mixtures

Physical combinations of two or more substances.
Three types: Solutions (homogeneous), Colloids (heterogeneous, do not settle), Suspensions (heterogeneous, particles settle).

Table: Types of Mixtures

Type	Homogeneous/Heterogeneous	Particle Size	Settling	Example
Solution	Homogeneous	Very small (molecules, ions)	No	Salt water, blood plasma
Colloid	Heterogeneous	Intermediate	No	Jell-O, cytosol
Suspension	Heterogeneous	Large	Yes	Blood (whole), sand in water

Differences Between Mixtures and Compounds

Mixtures do not involve chemical bonding; compounds do.
Mixtures can be separated by physical means; compounds require chemical means.
Mixtures can be homogeneous or heterogeneous; compounds are always homogeneous.

Solutions: Concentration and Measurement

Solvent: Substance present in greatest amount (usually water in the body).
Solute: Substance dissolved in solvent (e.g., glucose in blood).
Concentration can be expressed as percent, milligrams per deciliter (mg/dL), or molarity (M).
Molarity (M): Number of moles of solute per liter of solvent.
1 mole = molecules (Avogadro's number).

Structure of Atoms and Chemical Bonds

Electron Shells and Energy Levels

Electrons occupy regions called electron shells or energy levels.
Each shell holds a specific number of electrons:
- First shell: 2 electrons
- Second shell: 8 electrons
- Third shell: 18 electrons
Outermost shell is called the valence shell.
Electrons in the valence shell are involved in chemical reactions and bonding.

Octet Rule

Atoms tend to gain, lose, or share electrons to achieve 8 electrons in their valence shell (octet rule).
Exceptions: Small atoms (e.g., H, He) are stable with 2 electrons in their shell.

Types of Chemical Bonds

Ionic Bonds: Transfer of electrons from one atom to another, resulting in charged ions (e.g., NaCl).
Covalent Bonds: Sharing of electrons between atoms (e.g., O2, H2O).
Hydrogen Bonds: Weak attractions between a hydrogen atom and an electronegative atom (important in water and biological molecules).

Summary Table: Subatomic Particles

Particle	Charge	Location	Relative Mass (amu)
Proton	+1	Nucleus	1
Neutron	0	Nucleus	1
Electron	-1	Electron shell	0

Key Formulas and Equations

Number of Neutrons:
Molarity:
Avogadro's Number: molecules per mole

Applications in Anatomy & Physiology

Chemical reactions in the body are often irreversible and are influenced by the properties of atoms and molecules.
Understanding chemical bonds and energy is essential for studying metabolism, cellular respiration, and physiological processes.
Radioisotopes are used in medical imaging and cancer treatment.

Additional info: Some explanations and examples have been expanded for clarity and completeness based on standard Anatomy & Physiology curriculum.