miércoles, 20 de abril de 2011

Cell structure and Function

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


Lipid Bilayer
Is a continouse, oily boundary that prevent the free passage of water-soluble substance across it.

Wavelength
Is the destance from the peak of one wave to the peak beheing


Electron Microscope
Use magnet lenses to bend and of electrons, which cannot be different throught a glass lense

Transmission Elecron Microscope
Electron pass throught  a speciment and are used to make images
efect internal details

Scanning electron microscope
Direct a bean of electron back and foth across a surface



Organelle
membrane-bound compartment that carry out specialized metabolic function



Secretory pathway
moves new polypeptide chain from some ribosomes throughout ER and golgi body

Endocytic pathway
moves ion and molecules into the cytoplasm

vesicles
act like taxyand moves substances from one organelle to the nextç





-nucleus envelope
is a doble membrane 

Chromosome
is a doble stand for DNA
Peroxyne
hold enzymes theht digest fatty acids

                                                             

A close look to the Cell Membrane

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.