Basic Chemistry Concepts for Anatomy & Physiology

Basic Chemistry Concepts

Atomic Structure

Chemistry forms the foundation for understanding biological processes in Anatomy & Physiology. The structure and behavior of atoms and molecules are essential for grasping how the body functions at a molecular level.

• Atomic Number: The atomic number represents the number of protons in the nucleus of an atom. It determines the element's identity.

• Atomic Mass: The atomic mass is the sum of protons and neutrons in the nucleus. Electrons have negligible mass.

• Subatomic Particles: Atoms are composed of protons (positive charge), neutrons (neutral), and electrons (negative charge).

• Isotopes: Isotopes are atoms of the same element with different numbers of neutrons, resulting in different atomic masses.

• Charges and Masses:

  • Proton: +1 charge, mass ≈ 1 amu

  • Neutron: 0 charge, mass ≈ 1 amu

  • Electron: -1 charge, mass ≈ 0 amu

• Nucleus: The nucleus contains protons and neutrons; electrons orbit the nucleus.

• Element: An element is a substance made of only one type of atom, defined by its atomic number.

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

Chemical Bonds and Compounds

Atoms interact to form molecules through chemical bonds, which are crucial for the structure and function of biological molecules.

• Atomic Bonds: Atoms form bonds by sharing or transferring electrons to achieve stability.

• Covalent Bonds: Covalent bonds involve the sharing of electron pairs between atoms.

• Ionic Bonds: Ionic bonds result from the transfer of electrons from one atom to another, creating charged ions.

• Valence Electrons: Electrons in the outermost shell; involved in bond formation.

• Negatively Charged Ions: Called anions; formed when atoms gain electrons.

• Positively Charged Ions: Called cations; formed when atoms lose electrons.

• Compounds: Substances made of two or more elements chemically combined in fixed ratios. Example: $\text{H}_2\text{O}$ (water).

• Chemical Formula: Represents the elements and their ratios in a compound.

Properties of Matter

Matter is anything that has mass and occupies space. Understanding its properties is essential for studying biological systems.

• Matter: Anything that has mass and takes up space.

• Smallest Stable Unit: The atom is the smallest unit of matter that retains the properties of an element.

Enzymes and Chemical Reactions

Enzymes are biological catalysts that speed up chemical reactions in the body without being consumed.

• Role of Enzymes: Lower activation energy, increase reaction rates, and regulate metabolic pathways.

Acids, Bases, and pH

The balance of acids and bases is vital for physiological processes. The pH scale measures the concentration of hydrogen ions in solution.

• Acid: Substance that donates hydrogen ions ($\text{H}^+$) in solution.

• Base: Substance that accepts hydrogen ions or releases hydroxide ions ($\text{OH}^-$).

• pH Scale: Ranges from 0 (most acidic) to 14 (most basic). Lower pH = higher $\text{H}^+$ concentration.

• Buffer System: Maintains pH stability by neutralizing excess acids or bases.

• Hydrogen Ion Concentration: $\text{pH} = -\log_{10}[\text{H}^+]$

Organic Molecules and Macromolecules

Organic molecules are the building blocks of life. They include carbohydrates, lipids, proteins, and nucleic acids.

• Monomers: Single subunits that join to form polymers.

• Carbohydrates: Monomer is monosaccharide (e.g., glucose). Glycogen and starch are polysaccharides.

• Lipids: Building blocks are fatty acids and glycerol. Steroids are derived from cholesterol.

• Proteins: Monomers are amino acids. Each amino acid has a unique side group (R group).

• Nucleic Acids: Monomers are nucleotides, composed of a phosphate group, nitrogenous base, and sugar (ribose or deoxyribose).

• ATP: Adenosine triphosphate; provides energy for cellular processes.

Chemical Reactions in Biology

Chemical reactions are essential for metabolism and energy transfer in cells.

• Dehydration Reaction: Joins monomers by removing water.

• Hydrolysis: Breaks polymers into monomers by adding water.

Comparison Table: Covalent vs. Ionic Bonds

Bond Type	Electron Behavior	Example	Strength in Water
Covalent	Electrons shared	$\text{H}_2\text{O}$ (water)	Strong
Ionic	Electrons transferred	NaCl (table salt)	Weak (dissociates)

Key Terms and Definitions

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

• Salt: Ionic compound formed from acid-base reactions.

• Inorganic Compound: Compound not containing both carbon and hydrogen.

• Organic Compound: Compound containing carbon and hydrogen, often found in living organisms.

Additional info:

• These chemistry concepts are foundational for understanding physiological processes such as cellular respiration, muscle contraction, and nerve impulse transmission.