Cell Membrane Structure and Function

Fluid mosaic model
a mixed composition or a mosaic of phospholipids.

Transport proteins
let specific solutes diffuse through a membrane spaning channel.

Receptor proteins
Bind extracellular substances.

Recognition proteins
Indentity tags for each specie.

Adhesion proteins
help cells of the same type to locate each other and remain the proper tissue.

Communication Proteins
form channels that match up across the plasma membranes of two cells.

Concentration gradient
diferrences in number per unit volume of moleculesof a substance between two adjoining regions.

Diffusion
is the name for the net movement of like molecules or ions down concentration gradient.

Electric gradient
is a difference in electric charge between adjoining regions.

Pressure gradient
Difference in pressure exerted per unit volume between two adjoinig regions.

Osmosis

the diffusion of water across a selectively permeable membrane.

Hypotonic solution

the one with fewer solutes.

Hypertonic solution
The one having more solutes.

Isotomic solution
no net osmotic movement.

Hydrostatic pressure
pressure against the wall or membrane that contains it.

Osmotic pressure
one measure of the tendency of water to follow its water concentration gradient.

Endocytosis
a small patch of plasma membrane.

Exocytosis
a vesicle moves to the cell surface and then the protein-studded lipid bilayer of its membrane.

Phagocytosis
is a common endocytic pathway.

Cell Structure and Function

Nucleoid

A region of the cytoplasm that is not enclosed in a membranous sac.

Lipid Belayer

Oily boundaries that preventes the free passage of wter-soluble substances across it.



Wavelenght

Is the distance from the peak of one wave to the peak behind it.

Electron microscopes

use magnetic lenses to bend and diffract beams of electrons which cannot be diffracted.

Transmission electron microscopes

electrons pass through a specimen and are used to make images of its internal details.

Scanning electron microscopes

direct a beam of electrons back and forth across a surface of a specimen.

Organelles

The nucelus and other membrane-bounded sacs.

Secretory pathway

Move new polypeptide chains for some ribosomes through rough ER and Golgi bodies.

Endocytic pathway 

Moves ions and molecules into the cytoplasm.

Vesicles

Move substances from one organelles to the next in line.

Nuclear envelope

Double membrane system in which two lipid bilayers are pressed against each other.

Chromatin

The cell's collection of DNA and all proteins associated with it.

Chromosome

Is a double-stranded DNA molecule.

Peroxisomes

Hold enzymes that digest fatty acids, amino acids, and hydrogen peroxide.

Cell junctions

are molecular structures where a cel sends or recieves

Basal body

An oraganellles that started out as a centriole the source of a 9+2 array of microtubules in a cilium of flagellum.

Pseudopods

False feet used by the macrophages and amoebas.