BIOS-150: Human Cells -

Vocabulary practice flashcards covering basic cell anatomy, organelle functions, passive and active transport mechanisms, cell cycle stages, cell division, and cellular pathology concepts.

Cell

The smallest living unit that carries out all life functions; the human body contains approximately $37\text{ trillion}$ cells.

Cytology

The study of cell structure, function, and behavior.

Robert Hooke

Scientist who first used the term "cell" in 1665 after observing cork under a microscope.

Schwann & Schleiden

Scientists who proposed the Cell Theory in the 1800s, stating that all living things are made of cells.

Rudolf Virchow

Scientist known as the Father of Modern Pathology who showed that cells come only from pre-existing cells.

Cell Theory

The core biological principle stating that all living things are made of cells, cells are the basic units of structure and function, and all cells come from pre-existing cells.

Plasma Membrane

A thin, flexible, selectively permeable barrier composed of a phospholipid bilayer, proteins, cholesterol, and carbohydrates that separates the cellular interior from the external environment.

Phospholipid Bilayer

The main structural framework of the plasma membrane, consisting of two layers with hydrophilic heads facing outward and hydrophobic tails facing inward.

Passive Transport

Cellular movement of substances down their concentration gradient (from high to low concentration) without requiring energy.

Active Transport

Movement of substances against their concentration gradient (from low to high concentration) requiring energy in the form of ATP.

Diffusion

The passive movement of solute molecules from an area of high concentration to low concentration until equilibrium is reached.

Osmosis

The diffusion of solvent (water) molecules across a semi-permeable membrane toward a higher solute concentration.

Hypotonic Solution

A solution with a lower solute concentration than the inside of a cell, causing water to enter the cell and leading to cell swelling or lysis.

Hypertonic Solution

A solution with a higher solute concentration than the inside of a cell, causing water to leave the cell and leading to cell shrinking or shriveling.

Isotonic Solution

A solution with an equal solute concentration relative to the inside of the cell, resulting in equal water movement and normal cell shape.

Endocytosis

An active bulk transport process where cells engulf large external substances into the cell using vesicles.

Phagocytosis

A type of endocytosis commonly called "cell eating," where a cell engulfs large particles such as bacteria or cellular debris.

Pinocytosis

A type of endocytosis commonly called "cell drinking," where a cell takes in external fluid and dissolved substances.

Receptor-Mediated Endocytosis

A targeted form of endocytosis where specific molecules bind to cell surface receptors before being enclosed in coated vesicles.

Cytoplasm

The workspace inside the cell comprising cytosol, organelles, and the cytoskeleton.

Cytosol

The watery fluid contained within the cytoplasm containing dissolved nutrients, ions, proteins, and enzymes.

Nucleus

The control center of the cell that contains DNA and directs cell growth, division, repair, and protein production.

Nucleolus

A specialized region inside the nucleus responsible for manufacturing ribosomes.

Endoplasmic Reticulum (ER)

A continuous membrane network near the nucleus that is involved in protein and lipid synthesis.

Rough ER

Part of the endoplasmic reticulum studded with ribosomes that modifies and folds proteins for intracellular or extracellular use.

Smooth ER

Part of the endoplasmic reticulum lacking ribosomes that synthesizes lipids and detoxifies harmful substances.

Ribosomes

Structures found free in cytosol or bound to rough ER that assemble amino acids into proteins according to DNA instructions.

Golgi Complex

The organelle that modifies, packages, and routes proteins and lipids into vesicles for intracellular transport or exocytosis.

Lysosome

A membrane-bound organelle containing digestive enzymes that breaks down cellular waste, worn-out cell components, and foreign pathogens.

Mitochondria

Double-membraned organelles that produce ATP through cellular respiration using oxygen and glucose.

Cristae

The inner membrane folds of mitochondria that increase surface area for energy production.

Cell Cycle

The orderly sequence of events that a cell undergoes to grow, replicate its DNA, and divide.

Interphase

The non-dividing, longest phase of the cell cycle where the cell grows, replicates DNA, and prepares for cell division.

G1 Phase

The first growth stage of interphase where the cell increases in size and performs normal cellular functions.

S Phase

The synthesis stage of interphase in which DNA is completely replicated.

G2 Phase

The second growth stage of interphase where the cell conducts error checks on replicated DNA and prepares for mitosis.

Mitosis

The process of nuclear division in somatic cells divided into prophase, metaphase, anaphase, and telophase to form two identical daughter nuclei.

Cytokinesis

The division of the cytoplasm that follows mitosis to create two distinct, independent daughter cells.

Meiosis

A specialized cell division process involving two rounds of division that yields four genetically unique haploid gametes.

Apoptosis

Programmed cell self-destruction that eliminates damaged or unnecessary cells.

Cancer

A group of diseases characterized by uncontrolled cell division and resistance to normal cell cycle controls and apoptosis.

Metastasis

The process by which malignant cancer cells break away and spread to distant body sites through blood or lymphatic vessels.

Angiogenesis

The physiological process through which new blood vessels form from pre-existing vessels, often stimulated by tumors to supply nutrients.

Benign Tumor

A non-cancerous, slow-growing cell mass that remains localized and does not invade surrounding healthy tissue.

Malignant Tumor

A cancerous, rapidly growing tumor that invades nearby tissues and possesses the ability to metastasize.