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The basic unit of all living things

cell theory

idea that all living things are composed of cells, cells are the basic units of structure and function in living things, and new cells are produced from existing cells


the center of the atom which contains the protons and neutrons; in cells, structure that contains the cell's genetic material (DNA) and controls the cell's activities

nuclear envelope

layer of two membranes that surrounds the nucleus of a cell

Nuclear Pors

located in the envelope, controls the passage of molecules


dense masses of RNA and protein that manufacture ribosomes, several of these are located in the nucleus.


long strands of DNA found in the eukaryotic cell nucleus; condense to form chromosomes


threadlike structures made of DNA molecules that contain the genes

Plasma Membrane

thin outer boundary of a cell that regulates the traffic of chemicals between the cell and its surroundings


attracts water molecules


avoids water molecules

Tight Junctions

Membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid


specialized junctions that hold adjacent cell together, consist of dense plate at point of adhesion plus extracellular cementing material

Gap Junctions

cell junctions that allow cells to act as one whole unit


the tiny, fluid-filled tunnels characteristic of gap junctions that connect neighboring cells


The region of the cell between the cell membrane and the nucleus


the semifluid portion of the cytoplasm


tiny structures that carry out functions necessary for the cell to stay alive


Powerhouse of the cell, organelle that is the site of ATP (energy) production


non membrane bounded organelles responsible for protein synthesis

Rough ER

That portion of the endoplasmic reticulum studded with ribosomes.

Smooth ER

That portion of the endoplasmic reticulum that is free of ribosomes.

Transport Vesicles

vesicles in transit from one part of the cell to another

Golgi Appartus

a cell organelle that helps make and package materials to be transported out of the cell

Secretory Vesicles

carries proteins to the cell membrane so that they can be released into the extracellular fluid


An organelle containing digestive enzymes


membranous sacs containing enzymes used to break down hydrogen peroxide


A network of fibers that holds the cell together, helps the cell to keep its shape, and aids in movement


fine, threadlike proteins found in the cell's cytoskeleton


Spiral strands of protein molecules that form a tubelike structure


two tiny structures located in the cytoplasm near the nuclear envelope


short numerous hair like projections that move in a wavelike motion


whip-like structure used for motility


projections that increase the cell's surface area


A homogeneous mixture of two or more substances


substance in which a solute is dissolved to form a solution


substances dissolved in a liquid

Inracellular Fluid

Within the cell, are composed of water plus concentration of potassium and phosphates

Interstitial Fluid

liquid found between the cells of the body that provides much of the liquid environment of the body

Selective Permeability

a process in which a membrane allows some molecules to pass through while keeping others out


the process by which molecules move from an area of higher concentration to an area of lower concentration

Concentration Gradient

the difference in the concentration of molecules across a distance


diffusion of water through a selectively permeable membrane

Facilitated Diffusion

the transport of substances through a cell membrane along a concentration gradient with the aid of carrier proteins

Pressure Gradient

the rate at which atmospheric pressure declines over a given distance

Active Transport

the movement of materials through a cell membrane using energy

Solute Pumps

are protein carriers energized by ATP

Sodium-Potassium Pump

a carrier protein that uses ATP to actively transport sodium ions out of a cell and potassium ions into the cell

Vesicular Transport

transport of large particles and macromolecules across plasma membranes


process by which vesicles release their contents outside the cell


A membrane bound sac that contains materials involved in transport of the cell.


process by which a cell takes material into the cell by infolding of the cell membrane


process in which extensions of cytoplasm surround and engulf large particles and take them into the cell


process by which a cell takes in liquid from the surrounding environment


the first stage of the cell cycle


part of eukaryotic cell division during which the cell nucleus divides


division of the cytoplasm during cell division


the first stage of mitosis or meiosis in eukaryotic cell division, during which the nuclear envelope breaks down and strands of chromatin form into chromosomes


one of two identical "sister" parts of a duplicated chromosome


area where the chromatids of a chromosome are attached


second phase of mitosis, during which the chromosomes line up across the center of the cell


a phase of mitosis and meiosis in which the chromosomes separate


The phase of cell division during which the nuclear membrane re- appears and the chromosomes disappear

Cleavage Furrow

The first sign of cleavage in an animal cell; a shallow groove in the cell surface near the old metaphase plate.


sequence of DNA that codes for a protein and thus determines a trait


proteins that act as biological catalysts

Ribonucleic Acid


Transfer Ribonucleic Acid

RNA that translates mRNA to amino acids

Ribosomal Ribonucleic Acid

rRNA in full

Messenger Ribonucleic Acid

a transcription of a gene that combines with ribosomal RNA (rRNA) and transfer RNA (tRNA


process in which part of the nucleotide sequence of DNA is copied into a complementary sequence in RNA


3 line stanza


three-nucleotide sequence of mRNA that codes for a single amino acid


decoding of a mRNA message into a polypeptide chain


group of three bases on a tRNA molecule that are complementary to an mRNA codon

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