Cell Biology

cell theory

all living organisms are composed of 1 or more cells

prokaryotes

nucleotid, non membrane bound

eukaryotes

nucleous, nuclear envelope

cytoplasm

all ions, nutrients needed to carry out cellar activties(cytosol)

plasma membrane

An enclosed cell is separated from the surroundings. composed of a phospholipid bilayer with/embedded proteins

ribosome

to synthesis proteins

prokaryote cells

-no membrane bound

-no/minimal membrane bound organelles

-plasma membrane enclosed in rigid cell wall

gram positive

thick single layer (purple when stained)

gram negative

multilayer cell wall (pink or red when stained)

flagellum

-wip-like protein structure, rotates like scr

-for motion

endosymbiont theory

-2 free living cells

-1 cell (prokaryote) engulfed by other (endo part-endocytosis)

-engulfed prokaryote provided host with special metabolic abilities (symbiosis part)

evidence of endosymbiont theory

mitochondria and chloroplasts have two membrane (inner engulfed prokarytoe, outer from host cell)

biological membranes

-sheets of phospholipid molecules

-all biological membranes composed of them

phospholipid layer

-flexible matrix with selective permability

-animal membranes contain cholestrol-moderates the fluity of the membrane

intergated membrane proteins

-float in bilayer, many not in fixed position

-different membranes have different # of proteins

interior protein network these protein:

-reinforce membrane shape w/cytoskeleton
-some anchor proteins to cytoskeleton to prevent lateral movement

cell surface marker

-carbohydrates on the extracellular surface

-can be attached to lipids directly (called glycolipids)

Lipids are diverse

-vary in structure-length, polar head group, saturated, unsaturated fatty acids

-spontaneously form bilayers in water

transport

increase selectiveness of membrane (only certain substance pass)

enzymes

rxns are carried out on the interior surface of the membrane w/attached enzyme

surface receptor

extremly sensitive to chemical message

idenitiy

glycoproteins ID cells; ad in self recognition

adhesive

hold cells together, temporary or permament

attachment to cytoskeleton

surface proteins in need of anchoring to prevent movement or involved in cell-cell attachment

passive transport-diffusion

diffusion requires a concentration gradient

passive transport-selective (facilitated) diffusion

-requires protein channels

-Camer proteins, open to the exterior of the cell, fit a certain molecule

-channel and carrier proteins are molecule-specific, so selective diffusion

osmosis

movement of free h20 molecules, water moves in direction of solute

extrusion

single cell organism use contracile vacule to pump out h20

active transport

uses engery to move substances againest concentration gradient

sodium potassium pump

maintains low cytoplasmic na+ and high cytoplasmic k+

coupled transport

uses energy of one substance moving down its gradient to move another againest ist concentration gradient

contransport

-antiporter

-inward movement of na+ (down gradient) coupled outward movement of something againest gradient

bulk transport

-endo and exocytosis

-large polar molecules thta can not move through bilayer

endocytosis

plasma mem. envelops foods particles and fluids

exocytosis

-ejecting materials from cell

-reverse of endocytosis