Human Anatomy 1 Concepts

Monosaccharide

Definition: Single sugar unit (e.g., glucose, fructose) | Reason: Serves as the fundamental monomer building block for larger carbohydrates | Concept: Carbohydrate Monomers

Disaccharide

Definition: Two sugar units linked together (e.g., sucrose, lactose) | Reason: Formed when two monosaccharides combine via dehydration synthesis | Concept: Sugar Dimerization

Polysaccharide

Definition: Long chains of linked monosaccharides (e.g., glycogen, starch, cellulose) | Reason: Function as complex energy storage or structural support molecules | Concept: Carbohydrate Polymerization

Dehydration Synthesis

Definition: Chemical reaction joining monomers by removing a water molecule | Reason: An OH group from one monomer and an H from another form water, forging a covalent bond | Concept: Anabolic Polymerization

Hydrolysis

Definition: Chemical breakdown of polymers into monomers by adding water | Reason: Water molecules are consumed to break covalent bonds within macromolecular chains | Concept: Catabolic Cleavage

Peptide Bond

Definition: Covalent bond linking two adjacent amino acids | Reason: Joins the carboxyl group of one amino acid to the amino group of another in a polypeptide chain | Concept: Protein Primary Structure

Denaturation

Definition: Unfolding of a protein's 3D structure, losing its functional activity | Reason: Disrupts chemical interactions (hydrogen bonds, ionic bonds) holding tertiary structure together due to extreme pH or heat | Concept: Protein Structure and Function

Amphipathic

Definition: Molecule containing both hydrophilic (water-loving) and hydrophobic (water-fearing) regions | Reason: Enables molecules like phospholipids to self-assemble into biological membrane bilayers | Concept: Molecular Dual Polarity

Fluid Mosaic Model

Definition: Model describing the cell membrane as a dynamic phospholipid bilayer embedded with proteins | Reason: Phospholipids move laterally while proteins float within the layer like mosaic tiles | Concept: Membrane Dynamics

Selective Permeability

Definition: Property of membranes allowing only specific substances to pass through | Reason: Nonpolar core blocks large polar/charged substances, controlling cell entry and exit | Concept: Dynamic Homeostasis

Isotonic

Definition: Solution having equal solute concentration compared to the cell cytoplasm | Reason: Osmotic pressure is equal, resulting in no net movement of water across the membrane | Concept: Equilibrium Osmosis

Hypotonic

Definition: Solution having a lower solute concentration than the cell cytoplasm | Reason: Higher water concentration outside causes water to rush in, leading to cell swelling or lysis | Concept: Osmotic Influx

Hypertonic

Definition: Solution having a higher solute concentration than the cell cytoplasm | Reason: Lower water concentration outside causes water to exit the cell, leading to cell crenation/shriveling | Concept: Osmotic Efflux

Facilitated Diffusion

Definition: Passive transport across a membrane using specific channel or carrier proteins | Reason: Allows large or charged molecules to move down their concentration gradient without energy | Concept: Protein-Assisted Passive Transport

Active Transport

Definition: Transport of molecules against their concentration gradient requiring energy (ATP) | Reason: Transmembrane pumps use ATP to move substances from low to high concentration areas | Concept: Cellular Energy Utilization

Passive Transport

Definition: Movement of substances across a membrane down their concentration gradient without cellular energy | Reason: Driven purely by thermal kinetic energy and diffusion rules | Concept: Spontaneous Transport

Endocytosis

Definition: Bulk transport process moving large materials into a cell via membrane vesicles | Reason: Plasma membrane invaginates around extracellular material and pinches off internally | Concept: Inward Vesicular Transport

Phagocytosis

Definition: Type of endocytosis where a cell engulfs solid particles ("cell eating") | Reason: Form of bulk transport used by immune cells to engulf bacteria or cell debris | Concept: Cellular Ingestion

Pinocytosis

Definition: Type of endocytosis where a cell ingests extracellular fluid ("cell drinking") | Reason: Non-specific uptake of surrounding liquid and dissolved solutes into small vesicles | Concept: Fluid Uptake

Exocytosis

Definition: Bulk transport process releasing vesicle contents outside the cell | Reason: Intracellular vesicles fuse with the plasma membrane to export proteins or waste | Concept: Outward Vesicular Secretion

Cytosol

Definition: Fluid, gel-like matrix contained within the cell membrane | Reason: Composes the liquid portion where dissolved ions, enzymes, and nutrients reside | Concept: Intracellular Fluid Phase

Cytoplasm

Definition: Everything inside the plasma membrane including the cytosol and organelles, excluding the nucleus | Reason: Represents the total cellular contents within the outer boundary | Concept: Internal Cell Compartment

Rough Endoplasmic Reticulum

Definition: Membrane network studded with ribosomes that processes proteins | Reason: Ribosomes synthesize proteins directly into the lumen for folding and packaging | Concept: Protein Synthesis & Modification

Smooth Endoplasmic Reticulum

Definition: Membrane network lacking ribosomes that synthesizes lipids and detoxifies chemicals | Reason: Contains enzymes for steroid production, carbohydrate metabolism, and drug clearance | Concept: Lipid Synthesis & Detoxification

Golgi Apparatus

Definition: Stack of flattened membranes that modifies, sorts, and packages proteins | Reason: Receives transport vesicles from the ER and tags proteins for final cellular or extracellular destinations | Concept: Endomembrane Processing Center

Lysosome

Definition: Membrane-bound organelle containing acidic digestive enzymes | Reason: Performs autophagy by breaking down cellular waste, damaged organelles, and foreign material | Concept: Cellular Waste Degradation

Cytoskeleton

Definition: Network of microfilaments, intermediate filaments, and microtubules within the cell | Reason: Provides structural framework, organizes organelles, and facilitates intracellular transport | Concept: Structural Integrity & Motility

Cilia

Definition: Short, numerous hair-like projections on cell surfaces made of microtubules | Reason: Beat in coordinated waves to move fluids or mucus across tissue surfaces | Concept: Surface Fluid Transport

Flagella

Definition: Long, single tail-like projection made of microtubules | Reason: Rotates or undulates to propel the entire cell through fluid (e.g., sperm cells) | Concept: Whole-Cell Locomotion

Tight Junctions

Definition: Impermeable cell-cell junctions that seal adjacent membranes together | Reason: Form a leak-proof barrier preventing fluids and solutes from leaking between epithelial cells | Concept: Intercellular Sealing

Desmosomes

Definition: Anchoring cell junctions that rivet cells tightly together | Reason: Anchored to intermediate filaments to help tissues resist strong mechanical pulling forces | Concept: Structural Cell Anchoring

Gap Junctions

Definition: Communicating cell junctions made of protein channels (connexons) | Reason: Allow direct passage of ions, water, and small signaling molecules between adjacent cells | Concept: Intercellular Communication