CYTOLOGY

Cytology

The study of cells.

Cell Theory

The three principles that describe the properties of cells: 1. All living things are composed of cells, 2. All cells come from pre-existing cells, 3. Cells are the smallest units of life that perform all vital physiological functions.

Prokaryotic cells

Cells that lack a nucleus and membrane-bound organelles, typically single-celled, found in the domains Bacteria and Archaea.

Eukaryotic cells

Cells that have a nucleus and membrane-bound organelles, can be single or multicellular, found in the domain Eukarya.

Phospholipid Bilayer

A double-layered membrane formed by phospholipids with hydrophobic tails facing inward and hydrophilic heads facing outward.

Fluid Mosaic Model

The model describing the structure of the cell membrane as a mosaic of diverse protein molecules embedded in a fluid phospholipid bilayer.

Selectively Permeable

A property of the cell membrane that allows it to regulate the movement of substances in and out of the cell.

Passive Transport

Processes that move substances into or out of a cell without the use of energy.

Diffusion

The movement of molecules from an area of high concentration to an area of low concentration.

Facilitated Diffusion

A type of diffusion that uses carrier or channel proteins to help molecules cross the membrane without energy.

Osmosis

The diffusion of water across a selectively permeable membrane.

Hypotonic solution

A solution with a lower solute concentration compared to another solution.

Hypertonic solution

A solution with a higher solute concentration compared to another solution.

Isotonic solution

A solution with equal solute concentration compared to another solution.

Osmoregulation

The process by which organisms regulate the water and solute concentrations in their bodies.

Channel Proteins

Proteins that form pores in the cell membrane to allow specific ions or molecules to pass in and out.

Carrier Proteins

Proteins that bind to specific molecules and change shape to transport them across the cell membrane.

Active Transport

Processes that require energy (ATP) to move substances against their concentration gradient.

Bulk Transport

Movement of large amounts of materials into or out of the cell using vesicles.

Exocytosis

The process by which materials are expelled from the cell via vesicles.

Endocytosis

The process by which materials are brought into the cell via vesicles.

Phagocytosis

A form of endocytosis where cells engulf solid particles.

Pinocytosis

A form of endocytosis where cells take in liquid droplets.

Receptor-mediated Endocytosis

A selective form of endocytosis involving the binding of molecules to receptors on the cell surface.

Cytoplasm

The material within a cell, excluding the nucleus, that contains cytosol and organelles.

Ribosomes

Cell structures that synthesize proteins, found in both eukaryotic and prokaryotic cells.

Cytoskeleton

A network of protein fibers that provide structure and support to the cell.

Cilia

Short, hair-like structures that protrude from the cell membrane and are involved in movement.

Flagellum

A long, whip-like structure that enables mobility in cells.

Endoplasmic Reticulum (ER)

An organelle that modifies, synthesizes, and packages proteins and lipids.

Rough ER

Endoplasmic reticulum with ribosomes attached, involved in protein synthesis.

Smooth ER

Endoplasmic reticulum without ribosomes, involved in lipid synthesis and detoxification.

Golgi Apparatus

An organelle that modifies, sorts, and packages proteins for secretion.

Lysosomes

Organelles containing digestive enzymes for breaking down waste materials and cellular debris.

Peroxisomes

Organelles that contain enzymes for breaking down fatty acids and detoxifying harmful substances.

Mitochondria

Organelles that produce ATP through cellular respiration, known as the powerhouse of the cell.

Chloroplasts

Organelles in plant cells that carry out photosynthesis, converting sunlight into energy.

Nucleus

The organelle that houses the cell's DNA and is the control center of the cell.

Chromatin

The form of DNA in the nucleus that is loosely packed and translates into proteins.

Nuclear Pore

Protein channels in the nuclear membrane that allow the passage of materials in and out of the nucleus.

ATP (Adenosine Triphosphate)

The primary energy carrier in all living organisms.

Concentration Gradient

A difference in the concentration of a substance across a distance.

Homeostasis

The process by which living organisms regulate their internal environment to maintain stable conditions.

Cell Membrane

The outer boundary of the cell that separates interior from the external environment.

Hydrophobic

Refers to molecules that do not mix well with water.

Hydrophilic

Refers to molecules that readily interact with water.

Ion

An atom or molecule that has a net electric charge due to the loss or gain of one or more electrons.

Osmotic Pressure

The pressure required to prevent the flow of water across a semipermeable membrane.

Net Negative Charge

A condition where the overall charge within a cell is more negative than outside the cell.

Membrane-bound organelles

Cellular structures surrounded by membranes that perform specific functions.

Transport Vesicles

Small membrane-bound sacs that transport materials within the cell.

Cell Division

The process by which a parent cell divides into two or more daughter cells.

Cellular Respiration

The metabolic process by which cells convert glucose and oxygen into energy (ATP), carbon dioxide, and water.

Chromosomes

Structures within the nucleus that contain DNA, organized into a compact form.

Protein Synthesis

The process by which cells create proteins based on genetic instructions.

Cytosol

The gel-like substance within the cytoplasm that holds organelles in place.

Metabolic Pathways

Series of chemical reactions in a cell that lead to the synthesis or breakdown of molecules.

Plasma Membrane

Another term for the cell membrane that surrounds and protects the cell.

Vesicles

Small membrane-bound sacs that transport materials within the cell.

Cell Wall

A rigid outer layer of some cells, providing structural support and protection.

Intracellular Fluid (ICF)

The fluid contained within cells, differing in composition from extracellular fluid.

Extracellular Fluid (ECF)

The fluid outside of cells, which includes blood plasma and interstitial fluid.

Hydronium Ion

A positively charged ion formed when water accepts a proton (H+).

Chlorophyll

The green pigment found in chloroplasts, crucial for photosynthesis.

Nucleolus

A structure within the nucleus where ribosome production occurs.

Vacuole

A membrane-bound sac within a cell that stores substances.

Gene Expression

The process by which information from a gene is used to synthesize a functional gene product, usually a protein.

Protein Folding

The process where a protein structure assumes its functional shape or conformation.

Metabolism

The set of life-sustaining chemical reactions in organisms that involve energy transformation.

Signal Transduction

The process by which a chemical or physical signal is transmitted through a cell as a series of molecular events.

Glycoproteins

Proteins with carbohydrate chains attached that function in cell-cell recognition and signaling.