Fundamental Concepts in Chemistry and Biochemistry for Anatomy & Physiology

Study Guide - Smart Notes

Tailored notes based on your materials, expanded with key definitions, examples, and context.

Understanding the structure and properties of atoms and elements is essential for grasping the chemical basis of physiological processes.

Atom: The smallest unit of an element that retains its chemical properties. A neutral atom has equal numbers of protons and electrons.
Simplest Atom: Hydrogen is the simplest atom, consisting of one proton and one electron.
Atomic Structure: Atoms are composed of a nucleus (protons and neutrons) and electrons in orbitals.
Atomic Nmber: The number of protons in the nucleus; defines the element.
Mass Number: The sum of protons and neutrons in the nucleus.
Atomic Mass: The weighted average mass of an atom's isotopes.
Isotopes: Atoms of the same element with different numbers of neutrons.
Ions: Atoms or molecules that have gained or lost electrons, acquiring a charge.
Valence Shell: The outermost electron shell; determines chemical reactivity.
Octet Rules; Atoms tend to gain, lose, or share electrons to achieve eight electrons in their valence shell.

Example: Carbon-12 and Carbon-14 are isotopes of carbon, differing in neutron number.

Chemical bonds form when atoms interact to achieve stable electron configurations.

Ionic Bond: Formed by the transfer of electrons from one atom to another, resulting in oppositely charged ions (e.g., NaCl).
Covalent Bond: Formed by the sharing of electron pairs between atoms (e.g., H2O).
Polar Covalent Bond: Electrons are shared unequally, creating partial charges (e.g., water molecule).
Nonpolar Covalent Bond: Electrons are shared equally (e.g., O2).
Hydrogen Bond: Weak attraction between a hydrogen atom and an electronegative atom (e.g., between water molecules).
Free Radical: An atom or molecule with an unpaired electron; highly reactive.
Compound:

Example: Sodium (Na) loses an electron to become Na+, while chlorine (Cl) gains an electron to become Cl-, forming NaCl. (IONIC)

Chemical reactions involve the making and breaking of bonds, often accompanied by energy changes.

Kinetic Energy: Energy of motion.
Potential Energy: Stored energy due to position or structure.
Activation Energy: The minimum energy required to initiate a chemical reaction.
Enzyme: A biological catalyst that lowers activation energy and increases reaction rate.
Reversible Reaction: A reaction that can proceed in both forward and reverse directions.
Irreversible Reaction: Proceeds in one direction only.

Example: The hydrolysis of ATP to ADP is an exergonic (energy-releasing) reaction.

Biological systems often involve mixtures and solutions.

Solution: A homogeneous mixture of solute dissolved in solvent (e.g., salt water).
Colloid: A mixture with larger particles that do not settle (e.g., cytoplasm).
Suspension: A mixture with large particles that settle out over time (e.g., blood cells in plasma).
pH: A measure of hydrogen ion concentration;
Acid: Substance that donates H+ ions.
Base: Substance that accepts H+ ions.
Buffer: A system that minimizes changes in pH.

Example: Blood is buffered to maintain a pH around 7.4.

Carbohydrates are organic molecules composed of carbon, hydrogen, and oxygen, serving as energy sources and structural components.

Monosaccharides: Simple sugars (e.g., glucose, fructose).
Disaccharides: Two monosaccharides joined (e.g., sucrose = glucose + fructose).
Polysaccharides: Long chains of monosaccharides (e.g., glycogen, starch, cellulose).
Glycogen: The primary storage form of glucose in animals.
Function: Provide energy, serve as structural materials, and participate in cell recognition.

Example: Glycogen is stored in liver and muscle cells.

Lipids are hydrophobic molecules important for energy storage, membrane structure, and signaling.

Triglycerides: Composed of glycerol and three fatty acids; main form of stored fat.
Phospholipids: Major component of cell membranes; amphipathic (hydrophilic head, hydrophobic tails).
Steroids: Lipids with a four-ring structure (e.g., cholesterol, hormones).
Saturated Fatty Acids: No double bonds; solid at room temperature.
Unsaturated Fatty Acids: One or more double bonds; liquid at room temperature.
Monounsaturated vs. Polyunsaturated: Mono = one double bond; Poly = multiple double bonds.
Function: Energy storage, insulation, cell membrane structure, hormone synthesis.

Example: Phospholipids form the bilayer of cell membranes.

Proteins are polymers of amino acids with diverse functions in structure, catalysis, transport, and regulation.

Amino Acids: Building blocks of proteins; 20 standard types.
Peptide Bond: Covalent bond linking amino acids.
Primary Structure: Sequence of amino acids.
Secondary Structure: Local folding (α-helix, β-sheet).
Tertiary Structure: 3D folding of a single polypeptide.
Quaternary Structure: Association of multiple polypeptides.
Enzyme: Protein that catalyzes biochemical reactions.
Denaturation: Loss of protein structure and function due to environmental changes.

Example: Hemoglobin is a quaternary protein that transports oxygen in blood.

Nucleic acids store and transmit genetic information; ATP is the primary energy currency of the cell.

Nucleotide: Monomer of nucleic acids; consists of a sugar, phosphate, and nitrogenous base.
DNA: Deoxyribonucleic acid; stores genetic information.
RNA: Ribonucleic acid; involved in protein synthesis.
Pyrimidines: Cytosine, thymine (DNA), uracil (RNA).
Purines: Adenine, guanine.
ATP (Adenosine Triphosphate): Molecule that stores and transfers energy for cellular processes.

Example: ATP hydrolysis releases energy:

Biomolecule	Monomer	Main Function	Example
Carbohydrate	Monosaccharide	Energy, structure	Glucose, glycogen
Lipid	Fatty acid, glycerol	Energy storage, membranes	Triglyceride, phospholipid
Protein	Amino acid	Catalysis, structure, transport	Enzyme, hemoglobin
Nucleic Acid	Nucleotide	Genetic information	DNA, RNA

Hydrophilic vs. Hydrophobic: Hydrophilic molecules interact with water; hydrophobic molecules do not.
Solubility: Polar and ionic substances dissolve in water; nonpolar substances do not.
Enzyme Specificity: Enzymes are specific to substrates due to their active site structure.
Cofactor: Non-protein component required for enzyme activity (e.g., metal ions, vitamins).

Example: Lactase is an enzyme that specifically catalyzes the hydrolysis of lactose.

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