A Closer Look At Cell Membrames

Fluid Mosaic Model
A cell membrane has a miad composition of lipids and proteins

Adhesion Proteins
help cells of the same type locate each other and remain in the proper tissue

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

Receptor Proteins
bind extracellular substance ,such as hormones , that can trigger change in cell activities

Recognition Proteins
that are unique identity tags for each species

Passive Transporter
have a channel throught their

Active Transporter
movement with pump them throught

Concentration Gradient
is a difference in the number per unit volume of molecules of a substance between two adjaining regions

Diffusion
is the name for the net movementof like molecules or ions down a concentartion gradient

Electric Gradient
is simply a difference in electric charge between adjaining regions

Pressure Gradient
is a difference in pressure exterd per unit volume between two adjaining regions

Hypotonic Solution
is the one with fewer solute

Hypertonic Solution
the one having more solutes

Isolotonic Solution
show no net osmotic movement

Osmatic pressure
one measure of the tendence of water to follow its water

Endocytosis
a small patch of plasma membrane

Exocytosis
a vesicles moves to the cells surface

Phagocytosis
is a common endocytic pathway

Cell structure&Fuction

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

lipid bilayer
is a continuous,oily boundary that prevents the free passage of water-soluble substance.
Wavelength
is the distance from the peak of one wave to the peak behind it.

Electron microscopes
use magnetic lenses to bend and diffract beans of electrons,which cannot be diffracted hrough a glass lense.

Transmission electron microscopes
electron pass through a specimen and are used to make images of its internal details.
Scanning electron microscopes
direct a beam of electron back and forth across a surface of a specimen.

Organelles
they all start out life with a nucleus and other membrane bounded sacs.

Secretory pathway
moves new polypeptide chains from some ribosomes thriught ERand Golgi bodies.

Endocytic pathway
moves ions and molecules into the cytoplasm.

Nuclear envelope
is a double-membrane system in which two lipid bilayers are pressed against each other.

nucleolus

the construction site.

Chromatin
collection of DNA and all proteins associated with it-


Chromosomes
is double-stranted DNA molecule.


Endoplasmic Reticulum
is a flattened channel that starts at the nuclear envelope and folds back on itself repeatedly in cytoplasm.


Golgi Bodies
organelles in which the membrane channel folds bak on itself

Mitochodrion
is a type of organelle that specializes in ATP formation


Cell Junctions
are molecule structure where cell sends or receives signals .

Basal Body
finished array


pseudopods
false feet