A closer look Cell Membrane

Fluid mosaic model:make the cell membrane has a mixed composition on a mosaic a shorphol, gluolysen , sterol and proteins.

Receptor proteins: a bend extrcellular substance suchs as hormones that can  triggern change in cell activity.

 Recognition protein: identify tags for each species.

 Adhesion protein: help cells of the same type locate each other and remaijns in the proper tissue.



Concentration gradient: a difference in the number per unit volume molecules of a substance between two adjoining regions.

 Phagocytosis:is a common endocytic pathway.

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

Endocytosis: a small patch of plasma membrane balloons inward and pinches off inside the cytoplasm.

 

Osmotic pressure: one measure of the of the tendency of water to follow its water concentration gradient and move into that fluid.

Hydrostatic pressure: fluid exerts against the wall or membrane that contains it.

 

  Isotonic solution: show no net osmotic movement.

Osmosis: is the diffusion of water across the selectively permeable membrane to a region where the water concentration is lower.

Hypertonic solution: the one having more solute.

 

Hypotonic solution: it’s the one with fewer solutes.

 

 Pressure gradient: is a difference in pressure exerted per unit volume between two adjoining regions.

 

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

 

Diffusion: the net movement of like molecules or ions down the concentration gradient.

 

Active transporters: pump a solute across the membrane to the sides where it is more concentrated and less likely to move on its own.

Transport protein: let specific solute diffuse through a membrane-spanning channel in their interior or actively pump them through.

Cell Structure and Fuctions

Cell: smallest unit of life.

Nucleoid:a region of the cytoplasm that is not enclosed in a membrane sac.

Lipid Bilayer:is a continuous, oily boundary that prevents the free passage of water-solute substance across it.

Wavelength: is the distance from the peak of one wave to the peak behind it.

Electron microscope:use magnetic lenses to bend and diffract beams of electrons, which cannot be diffracted thought glass lens.
 
transmission electron microscope:electrons pass throught and specimen and are used to make images of its internal message.

Scanning Electron Microscope: direct a beam of electron back and forth across the surface of a specimen.

Organelles: Start out life with a nucleus and a membrane bounded sac.
 
Secretory Pathway: moves new polypeptide chains fom some ribosomes to ER or golgi bodies.

Endocytic Pathway: Moves ions and molecules into cytoplasm.



Vesicles: move substance fom one organelles to the next in life.


Nuclear Envelope: double-membrane system in which to lipid bilayers are press against each other.

Chromosomes: is a DNA molecules and its associated with proteins.

Chromatin: collection of DNA and all protein associated with it.

Cell Junction: molecules structue whee a cell send and recives signals.

Basal Body: barrel-shaped structue produces and organize microtubules into the 9+2 array,then it remains below the finished array.