Ch. 3 Cells: The Living Units

Front 1

Define Cell

Back 1

A cell is the basic structural and functional unit of living organisms

Front 2

List 3 major regions in a cell and their function

Back 2

plasma membrane-a fragile barrier, is the outer boundary of the cell
cytoplasm-intracellular fluid that is packed with organelles
nucleus-controls cellular activities and typically it lies near the cell's center

Front 3

Describe the chemical compostion of the plasma membrane and relate it to membrane functions

Back 3

It defines the extnet of a cell, therby separating two of the body's major fluid compartments; the intracellular fluid within cells and the extracellular fluid outside cell. cell membrane---plasma membrane

Front 4

comapare the structure and function of tight junctions, desomones, and gap junctions

Back 4

tight junctions-intergral protein molecules in the plasma membranes of adjacent cells fuse together,forming an impermeable junction that encircles the cell
desomones-binding bodies are anchoring juctions-mechanical coupling scattering like rivets alon the sides of abutting cells that prevent their separation
gap junctions-is a communicating junction between adjacent cells

Front 5

active transport

Back 5

the cell provides the energy to move substances across the cell membrane

Front 6

passive transport

Back 6

substances cross the membrane without any energy input from the energy from the cell

Front 7

simple diffusion

Back 7

nonpolar and lipidsoluble substances diffuse directly thru the lipid bilayer. O concentration is always higher in the blood than in the tissue cells, O contiously diffuses from the blood into the cells

Front 8

facillitated diffusion

Back 8

binds to protein carriers in the membrane and is ferried across r moves thru water filled protein channels

Front 9

Osmosis

Back 9

the diffusion of a solvent, such as h2o thru a selectively permeable membrane is osmosis

Front 10

primary active transport

Back 10

hydrolysis of ATP results in the phosphorylation of the transport protein. This step causes the protein to change its shape in such a manner that it "pumps" the bound solute across the membrane

Front 11

Secondary Active Transport

Back 11

a singel ATP powered pump, such as Na+ - K+ pump, can indirectly drive the secondary active transport of several other solutes

Front 12

Exocytosis

Back 12

vesicular transport processes that eject substances from the cell interior into the extracellular fluidare called exocytosis( out of the cell)

Front 13

Endocytosis

Back 13

Those which the cell ingests small patches of the plasma membrane and moves substances from the cell exterior to the interior are called endocytosis

Front 14

Pinocytosis

Back 14

(cell drinking) also called fluid-phase endocytosis, a bit of infolding plasma membrane ( which beginsas a clathrin-coated pit) surrounds a very small volume of extracellular fluid containing dissolved molecules

Front 15

Phagocytosis

Back 15

(cell eating) is the type of endocytosis in which the cell engulfs some relatively large or solid material, such as a clump of bacteria, cell debris, or inanimate particles (asbestos fibers or glass)

Front 16

Receptor mediated endocytosis

Back 16

is the main mechanism for the specific endocytosis and transcytosis and transcytosis of most macromolecules by body cells and its exquistely selective

Front 17

membrane potential

Back 17

(voltage) across the membrane. voltage is electrical potential energy resulting from the separtion of oppositely charged particles

Front 18

cytosol

Back 18

is the viscous semitransparent fluid in which the other cytoplasmic elements are suspended. it is a complex mixture with properties of both a colloid and a true solution. dissolved in the cytosol, which is largely water, are proteins, salts, sugars, and a variety of other solutes

Front 19

mitchondria

Back 19

are threadlike or lozenge shaped membranous organelles. in living cells they squirm, elongate, and change shape almost contiously

Front 20

inclusions

Back 20

are chemical substances that may or may not be present, depending on cell type. ex include; stored nutrients, such as glycogen granules abudant in the liver and muscle cells; lipid dropelts common in fat cells; pigment (melanin) granules; seen in certain cells of skin and hair; water-containing vacuoles; and crystals of various types

Front 21

ribosomes

Back 21

are small, dark-staining garnules composed of proteins and a variety of RNAs called ribosomal RNAs.Ribosomes are sites of protein synthesis

Front 22

endoplasmic reticulum

Back 22

(network w/in the cytoplasm) is an extensive system of interconnected tubes and parallel membranes enclosing fluid-filled cavities or cisternae. accounts for half of the cell's membrane

Front 23

golgi apparatus.

Back 23

consists of stacked and flattened membranous sacs, shaped like hollow dinner plates, associated with swarms of tiny membranous vesicles. it is the traffic director for cellular proteins