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55 Cards in this Set

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A basic unit of living matter separated from its enviornment by a plasma membrane; the fundamental strctural unit of life.
A short appendage that propels some protists through the water and moves fluids across the surface of many tissue cells in animals.
Cilium (plural, cilia)

In common with eukaryotic flagella, cilia have a 9 + 2 arrangement of microtubles covered by the cell's plasma membrane.
A protective layer exernal to the plasma membrane in plant cells, bacteria, fungi, and some protists; protects the cell and helps maintain its shape.
Cell wall
A structure in an animal cell composed of microtubule triplets arranged in a 9 + 0 pattern.

An animal cell usually has a pair of centrioles within each of its centosomes.
An organelle found in plants and photosynthetic protists. Enclosed by two concentrated membrane, it absorbs sunlight and uses it to power the synthesis of organic food molecules (sugars).
The combination of DNA and proteins that constitutes chromosomes; often used to refer to the diffuse, very extended form taken by the chromosomes when a eukaryotic cell is not dividing.
A threadlike, gene-carrying structure found in the nucleus of a eukaryotic cell and the most visible during mitosis and meiosis; also, the main gene-carrying structure of a prokaryotic cell.

Chromosomes consist of chromatin.
An increase or decrease in the density of a chemical substance in an area.
Concentration gradient

Cells often maintain concentration gradients of ions across their membranes.
A meshwork of fine fibers in the cytoplasm of a eukaryotic cell, includes microfilaments, intermediate filaments, and microtubules.
Everything inside a cell between the plasma membrane and the nucleus; consists of a semifluid medium and organelles.
An organism with eukaryotic cells.
A type of cell that has a membrane-enclosed nucleus and other membrane-enclosed organelles. All organisms except bacteria and archaea are composed of these.
Eukaryotic cells
The domain of eukaryotes, organisms made of eukaryotic cells' includes all of the protists, plants, fungi, and animals.
An extensive membranous network in a eukaryotic cell, continuous with the outer nuclear membrane and composed of ribosome-studded (rough) and riblsome-free (smooth) regions.
Endoplasmic Reticulum (ER)
A network of interconnected membranous sacs in a eukaryotic cell's cytoplasm.
Rough endoplasmic reticulum (rough ER)

Rough ER membranes are studded with riblsomes that make membrane proteins and secretory proteins. The rough ER constructs membrane from phospholipids and proteins.
A network of interconnected membranous tubules in a eukaryotic cell's cytoplasm.
Smooth endoplasmic reticulum (smooth ER)

Smooth ER lacks ribosomes. Enzymes embedded in the smooth ER membrane function in the synthesis of certain kinds of molecules, such as lipids.
A substance in which the cells of an animal tissue are embedded, consists of protein and polysaccharides.
Extracellular matrix
The movement of materials out of the cytoplasm of a cell via membranous vescles or vacuoles.
The movement of materials into the cytoplasm of a cell via membranous vesicles or vacuoles.
A description of membrane structure, depicting a cellular membrane as a mosaic of diverse protein molecules embedded in a fluid bilayer made of phospholipid molecules.
Fluid mosaic
The passage of a substance across a biological membrane down its concentration gradient, aided by specific transport proteins.
Facilitated diffusion
An organelle in eukaryotic cells consisting of stacks of membranous sacs that modify, store, and ship products of the endoplasmic reticulum.
Golgi apparatus
A digestive organelle in eukarytoic cells; contains hydrolytic enzymes that digest the cell's food and wastes.
An organelle in eukaryotic cells where cellular respiration occurs. Enclosed by two concentric membranes, it is where most of the cell's ATP is made.
Mitochondrion (plural, mitochondria)
(1) An atom's central core, containing protons and neutrons. (2) The genetic control center of a eukaryotic cell.
Nucleus (plural, nuclei)
A structure within the nucleus of a eukaryotic cell where the ribosomal RNA is made and assembled with proteins to make ribosomal subunits; consists of parts of the chromatin DNA, RNA transcribed from the DNA, and proteins imported from the cytoplasm.
Nucleolus (plural, nucleoli)
A double membrane, perforated with pores, that encloses the nucleus and separates it from the rest of the eukaryotic cell.
Nuclear envelope
The diffusion of a substance across a biological membrane, without any input of energy.
Passive transport
The process by which plants, autotrophic protists, and some bacteria use light energy to make sugars and other organic food molecules from carbon dioxide and water.
Cellular "eating"; a type of endocytosis whereby a cell engulfs macromolecules, other cells, or particles into its cytoplasm.
Cellular "drinking"; a type of endocytosis in which the cell takes fluid and dissolved solutes into small membranous vesicles.
The thin layer of lipids and proteins that sets a cell off from its surroundings and acts as a selective barrier to the passage of ions and molecules into and out of the cell; consists of a phospholipid bilayer in which are embedded molecules of protein and cholesterol.
Plasma (cell) membrane
A temporary extension of an amoeboid cell.
Pseudopodium (plural, pseudopodia)

Pseudopodia function in moving cells and engulfing food.
A structure with a specialized function within a cell.
The diffusion of water across a selectively permeable membrane.
The control of the gain and loss of water and dissolved solutes in an organism.
A cell organelle consisting of RNA and protein organized into two subunits and functioning as the site of protein synthesis in the cytoplasm.

The ribosomal subunits are constructed in the nucleolus.
The type of ribonuleic acid that, together with proteins, makes up ribosomes; the most abundant type of RNA.
Ribosomal RNA (rRNA)
On or in a cell, a specific protein molecule whose shape fits that of a specific molecular messenger, such as a hormone.
A property of biological membranes that allows some substances to cross more easily than others and blocks the passage of other substances altogether.
Selective permeability
The spontaneous movement of particles of any kind from where they are more concentrated to where they are less concentrated.
Diffusion (simple)
A membrane protein that transports sodium ions out of, and potassium ions into, a cell against their concentration gradients. The process is powered by ATP.
Sodium-potassium (Na+ -K+) pump.
(1) The discharge of molecules synthesized by a cell. (2) In the vertebrate kidney, the discharge of wastes from the blood into the filtrate from the nephron tubules.
The ability of a solution to cause a cell within it to gain or lose water.
In comparing two solutions, the one with the lower concentration of solutes.
Hypotonic solution
In comparing two solutions, the one with the greater concentration of solutes.
Hypertonic solution
A solution having the same solute concentration as another solution.
Isotonic solution
A membrane-enclosed sac, part of the endomembrane system of a eukaryotic cell, having diverse functions.
The movement of a substance across a biological membrane against its concentration gradient, aided by specific transport proteins and requiring input of energy (often as ATP)
Active transport
The thickest of three main kinds of fibers making up the cytoskeleton of a eukaryotic cell; a straight, hollow tube made of globular proteins called tubulins.

Microtubules form the basis of the structure and movement of the cilia and flagella.
A phenomenon that occurs in plants in a hypertonic solution. The cell loses water and shrivels, and its plasma membrane pulls away from the cell wall, usually killing the cell.
Meaning "nucleus-like" in a prokaryotic cell.

A prokaryotic cell lacks a nucleus (its name comes from the Greek pro meaning before, and karyon, meaning kernel- referring to the nucleus. So prokaryotic means before there was a nucleus.
The region in a prokeryotic cell consisting of a concentrated mass of DNA that is NOT membrane bound!
Nucleoid region
A long surface projection that propels a prokaryotic cell through its liquid enviornment.
Prokaryotic flagellum (plural, flagella)

It is completely different from the flagellum of a eukaryotic cell.
A short projection on the surface of a prokaryotic cell that helps the prokaryote attach to other surfaces.
Pilus (plural, pili)

Specialized sex pili are used in conjugation to hold the mating cells together.