Chapter 2: Chemistry of Life – Study Notes for Anatomy & Physiology

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Water is a vital molecule in biological systems, playing a key role in maintaining homeostasis and supporting cellular functions.

Organic vs. Inorganic Compounds: Organic compounds contain carbon and are typically found in living organisms (e.g., carbohydrates, proteins, lipids, nucleic acids). Inorganic compounds do not contain carbon-hydrogen bonds (e.g., water, salts).
Universal Solvent: Water is called the universal solvent because it can dissolve a wide variety of substances due to its polarity.
Types of Ions from Water: Water can dissociate into hydrogen ions (H+) and hydroxide ions (OH-).

Acids and bases are substances that alter the concentration of hydrogen ions in a solution, affecting the pH and biological processes.

Difference Between Acid and Base: Acids release H+ ions in solution, while bases accept H+ ions or release OH- ions.
pH Measurement: pH is a measure of hydrogen ion concentration; it ranges from 0 (acidic) to 14 (basic), with 7 being neutral.
Acidic vs. Basic Solutions: Acidic solutions have higher concentrations of H+ ions, while basic solutions have lower concentrations.

Formula:

These are chemical reactions essential for building and breaking down organic molecules in living organisms.

Dehydration Synthesis: A process where two molecules are joined by removing a water molecule, forming larger molecules like polymers.
Hydrolysis: The breakdown of polymers into monomers by adding water.
Monomer and Polymer: A monomer is a single subunit; a polymer is a chain of monomers.
Example: Glucose (monomer) can be joined to form starch (polymer).

Carbohydrates are organic molecules that serve as energy sources and structural components in cells.

Building Blocks: Monosaccharides (simple sugars) are the monomers of carbohydrates.
Polymers: Polysaccharides (e.g., starch, glycogen, cellulose) are polymers of carbohydrates.
Functions: Provide energy, store energy, and serve as structural materials.

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

Classes of Lipids: Triglycerides, phospholipids, and steroids.
Triglycerides: Composed of glycerol and three fatty acids; main function is energy storage.
Saturated vs. Unsaturated Fatty Acids: Saturated fatty acids have no double bonds; unsaturated fatty acids have one or more double bonds.
Phospholipids: Have a hydrophilic (water-attracting) head and hydrophobic (water-repelling) tails, forming the basis of cell membranes.
Phospholipid Bilayer: The structure of cell membranes; hydrophilic heads face outward, hydrophobic tails face inward.

Lipid Class	Main Components	Function
Triglycerides	Glycerol + 3 Fatty Acids	Energy Storage
Phospholipids	Glycerol + 2 Fatty Acids + Phosphate Group	Membrane Structure
Steroids	Four Fused Carbon Rings	Hormones, Membrane Stability

Proteins are complex molecules that perform a wide range of functions in cells, including catalysis, transport, and structural support.

Monomers: Amino acids are the building blocks of proteins.
Levels of Protein Structure: Primary (amino acid sequence), secondary (alpha helices and beta sheets), tertiary (3D folding), and quaternary (multiple polypeptides).
Functions: Enzymes, transport proteins, structural proteins, signaling molecules.

Nucleic acids store and transmit genetic information. The two main types are DNA and RNA.

Monomers: Nucleotides, each consisting of a sugar, phosphate group, and nitrogenous base.
DNA vs. RNA: DNA contains deoxyribose sugar and is double-stranded; RNA contains ribose sugar and is single-stranded.
Bases in DNA: Adenine (A), Thymine (T), Cytosine (C), Guanine (G).
Bases in RNA: Adenine (A), Uracil (U), Cytosine (C), Guanine (G).
Functions: DNA stores genetic information; RNA is involved in protein synthesis.

Feature	DNA	RNA
Sugar	Deoxyribose	Ribose
Strands	Double	Single
Bases	A, T, C, G	A, U, C, G
Function	Genetic Information Storage	Protein Synthesis

ATP (adenosine triphosphate) is the primary energy carrier in cells, essential for metabolism and cellular activities.

ATP Hydrolysis: The breakdown of ATP releases energy for cellular processes.
Importance: ATP hydrolysis provides energy for muscle contraction, active transport, and biosynthesis.
Site of ATP Production: Most ATP is produced in the mitochondria via cellular respiration.

Formula:

Additional info: Some explanations and table entries were expanded for clarity and completeness.