Fundamental Concepts in Chemistry and Biochemistry for Anatomy & Physiology

Chemistry Foundations

Definitions and Basic Concepts

• Chemistry: The scientific study of matter, its properties, composition, and the changes it undergoes during chemical reactions.

• Matter: Anything that has mass and occupies space.

• Mass: A measure of the amount of matter in an object, typically measured in grams or kilograms.

Subatomic Particles

• Protons: Positively charged particles found in the nucleus of an atom.

• Neutrons: Neutral particles (no charge) also located in the nucleus.

• Electrons: Negatively charged particles that orbit the nucleus in electron shells.

• Charge of Subatomic Particles:

  • Proton: +1

  • Neutron: 0

  • Electron: -1

Atomic Structure

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

• Isotope: Atoms of the same element with different numbers of neutrons.

• Radioisotope: An isotope with an unstable nucleus that emits radiation as it decays.

• Atomic Weight: The average mass of atoms of an element, accounting for isotopes.

• Electron Shells: Energy levels where electrons are found; shells fill in a specific order.

Chemical Bonds and Molecules

Chemical Bonds

• Chemical Bond: The force that holds atoms together in molecules and compounds.

• Molecule: Two or more atoms chemically bonded together.

• Compound: A substance formed from two or more different elements bonded together.

Types of Ions

• Cation: An ion with a positive charge (lost electrons).

• Anion: An ion with a negative charge (gained electrons).

Bonding Types

• Ionic Bond: Formed when electrons are transferred from one atom to another, creating oppositely charged ions that attract.

• Covalent Bond: Formed when atoms share electrons.

• Hydrogen Bond: A weak bond between a hydrogen atom (attached to an electronegative atom) and another electronegative atom.

Properties of Water and Energy Concepts

Surface Tension

• Surface Tension: The cohesive force at the surface of a liquid that makes it behave as if covered by a stretched elastic membrane.

• Example: Water droplets forming beads on a surface.

Energy Types

• Kinetic Energy: Energy of motion.

• Potential Energy: Stored energy due to position or structure.

Chemical Reactions

Decomposition and Synthesis Reactions

• Decomposition Reaction: A chemical reaction where a compound breaks down into simpler substances.

• Synthesis Reaction: A reaction where two or more substances combine to form a more complex compound.

• Hydrolysis: Decomposition reaction involving water to break bonds.

• Dehydration Synthesis: Synthesis reaction where water is removed to form a bond.

Enzymes and Metabolism

Role of Enzymes

• Enzyme: Biological catalyst that speeds up chemical reactions without being consumed.

Endergonic and Exergonic Reactions

• Endergonic Reaction: Absorbs energy; products have more energy than reactants.

• Exergonic Reaction: Releases energy; products have less energy than reactants.

Nutrients and Metabolites

• Nutrient: Substance required for growth, maintenance, and repair of the body.

• Metabolite: Any substance produced or used during metabolism.

Organic and Inorganic Compounds

Classification

• Organic Compounds: Contain carbon and hydrogen; examples include carbohydrates, lipids, proteins, and nucleic acids.

• Inorganic Compounds: Do not contain both carbon and hydrogen; examples include water, salts, acids, and bases.

Acids, Bases, and Buffers

Definitions

• Acid: Substance that releases hydrogen ions ($H^+$) in solution.

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

• Electrolyte: Substance that dissociates into ions in solution and conducts electricity.

• Buffer: Substance that minimizes changes in pH by accepting or donating $H^+$ ions.

pH Scale

• pH: A measure of hydrogen ion concentration; scale ranges from 0 (acidic) to 14 (basic).

• Formula: $pH = -\log[H^+]$

Biological Macromolecules

Carbohydrates

• Carbohydrates: Organic molecules composed of carbon, hydrogen, and oxygen; primary energy source.

• Example: Glucose ($C_6H_{12}O_6$)

Lipids

• Lipids: Hydrophobic organic molecules including fats, oils, and fatty acids; used for energy storage and cell membranes.

• Fatty Acids: Long hydrocarbon chains with a carboxyl group; building blocks of lipids.

Proteins

• Proteins: Polymers of amino acids; perform structural, enzymatic, and regulatory functions.

Nucleic Acids

• Nucleic Acids: DNA and RNA; store and transmit genetic information.

• DNA: Deoxyribonucleic acid; double helix structure.

• RNA: Ribonucleic acid; single-stranded.

ATP and Cellular Energy

ATP: Adenosine Triphosphate

• ATP: The primary energy carrier in cells; provides energy for cellular processes.

• Importance: ATP stores energy in its high-energy phosphate bonds and releases it when needed for biological work.

• ATP Hydrolysis Equation: $ATP + H_2O \rightarrow ADP + P_i + \text{energy}$

Summary Table: Key Chemical Concepts

Concept	Definition	Example
Atom	Smallest unit of matter	Hydrogen atom
Isotope	Atom with same number of protons, different neutrons	Carbon-12, Carbon-14
Ionic Bond	Transfer of electrons	NaCl (sodium chloride)
Covalent Bond	Sharing of electrons	H2O (water)
Enzyme	Biological catalyst	Amylase
ATP	Cellular energy molecule	ATP hydrolysis