Cell Biology: Structure, Transport, and Specialization

Practice vocabulary flashcards covering prokaryotes, eukaryotes, cell membrane structure, passive and active transport, cellular specialization, and the history and principles of cell theory.

Cell Membrane

A selectively permeable fluid mosaic structure made of phospholipids, proteins, and carbohydrates that separates the living cell from its non-living surroundings and controls traffic in and out of the cell.

Phospholipid

A lipid containing phosphorus with a hydrophilic phosphate group head that likes water and hydrophobic fatty acid tails that do not like water.

Amphiphilic

A term describing a molecule that has both a polar part and a non-polar part, such as a phospholipid.

Prokaryotic Cell

A cell type with no nucleus or membrane-bound organelles that reproduces using binary fission and contains circular DNA, ribosomes, and sometimes a cell wall.

Eukaryotic Cell

A cell type found in plants, fungi, and animals that contains a nucleus and membrane-bound organelles and reproduces using mitosis.

Peripheral Proteins

Proteins loosely bound to the surface of the membrane that help identify cells by their outer surface like a cell nametag (antigens).

Integral Proteins

Proteins that penetrate the lipid bilayer and usually span across the whole membrane, primarily functioning to transport substances.

Cholesterol (in membrane)

A component of the cell membrane that helps keep it from getting too firm or too fluid, such as during winter.

Unsaturated Fatty Acids (in membrane)

Fatty acids in phospholipids that make the membrane more fluid and flexible.

Saturated Fats (in membrane)

Lipids that cause membrane phospholipids to become more packed and solid.

Cell-Cell Recognition

The ability of a cell to distinguish one cell from another, aided by membrane carbohydrates and antigens, which is important in organ and tissue development and immune rejection of foreign cells.

Passive Transport

The cellular process of moving molecules and other substances across membranes from an area of high to low concentration using little to no energy.

Diffusion

The movement of molecules in a solution from an area of high concentration to an area of low concentration until the concentration is the same throughout (equilibrium).

Osmosis

The diffusion of water through a selectively permeable membrane from an area of high water concentration to low water concentration.

Selectively Permeable

A characteristic of a membrane that allows only certain materials to pass through while blocking others (such as allowing water but not sugar).

Hypertonic

A solution with more solute and less water (concentrated); cells placed in a hypertonic environment lose water and shrink.

Hypotonic

A solution with more water and less solute (dilute); cells placed in a hypotonic environment take in water and swell.

Isotonic

A solution where the concentration of solute and water is the same inside and out; the cell stays the same size.

Osmotic Pressure

Pressure on the hypertonic side of a selectively permeable membrane caused by osmosis.

Turgor Pressure

The main force exerted outward against the cell wall by the water and cell contents in plant cells and bacteria, resulting from osmotic pressure.

Plasmolysis

The loss of water from a cell, evident when the cell contents pull away from the rigid cell wall as water moves out by osmosis.

Facilitated Diffusion

The movement of specific molecules across cell membranes through protein channels with the aid of a carrier protein, passing through an integral protein.

Channel Diffusion

Passive diffusion involving channel proteins where materials move through an aqueous pore and ions move through ion gates from high to low concentration.

Active Transport

The movement of chemical substances across the cell membrane against the concentration gradient (from low to high concentration), involving carrier proteins and requiring energy.

Sodium Potassium Pump

A carrier protein mechanism that uses energy to pump sodium ions out of the cell and pump potassium ions into the cell.

Endocytosis

The active process in which the cell membrane surrounds a particle or fluids and encloses the target in a vesicle, bringing it into the cell.

Pinocytosis

A form of endocytosis in which the cell takes in extracellular fluids.

Phagocytosis

A form of endocytosis in which a cell engulfs a large particle, such as a white blood cell engulfing harmful bacteria for food or defense.

Exocytosis

The process by which large amounts of material or substances are released from the cell through a vesicle that fuses to the cell surface membrane.

Unicellular Organism

An organism made up of only one cell; these dominate life on Earth.

Multicellular Organism

An organism made up of many cells that are specialized to perform different tasks.

Cell Specialization

The process by which cells throughout an organism develop in different ways to perform different tasks.

Red Blood Cells

Specialized animal cells that carry oxygen and have no nucleus in order to maximize surface area.

Neurons

Specialized animal cells that transmit signals, equipped with a long axon to carry information quickly.

Root Hair Cell

A specialized plant cell that absorbs water from the soil, featuring a long extension to maximize surface area.

Xylem Cell

A specialized plant cell that carries water throughout the plant, having no ends to allow faster transport.

Levels of Organization

The organizational hierarchy of living things progressing from individual cell to tissues, organs, organ systems, and organism.

Cell Theory

The foundational biological principle stating that: 1) All living things are made of cells, 2) Cells are the basic unit of structure and function of living things, and 3) New cells are produced from living cells.

Roberte Hook

The scientist who discovered cells in 1665 by looking at a thin slice of cork, describing them as tiny boxes and believing they only existed in plants and fungi.

Anton van Leuwenhoek

The scientist who in 1673 used a hand-made microscope to observe pond scum, discovered single-celled organisms called "animalcules", and established that cells exist in animals too.

Matthais Schlieden

The scientist who concluded in 1838 that all plant parts are made of cells.

Theodor Schwann

The scientist who stated in 1839 that all animal tissues are made of cells.

Rudolf Virchow

The scientist who concluded in 1858, after extensive study of cellular pathology, that cells must arise from pre-existing cells.