vocabulary # 5

Fluid Mosaic Model

A mixed composition or a mosaic of phospholipids, glycolipids, sterols and proteins.

Transport Proteins

Passively let specific solutes diffuse through a menbrene-spanning channel in their interior or actively pump them through.

Recetor Proteins

Are designed so special molecules can bind to them, and send messages to the cell that trigger some sort of reaction within the cell.

Recognition Proteins

Indentify the type of substances that enter the cell.

Adhesion Proteins

Join cells to form a tissue.

Comunication Proteins

Comunicate a cell to another

Diffusion

The process by which molecules spread from areas of high concentratiion, to areas of low concentration. When the molecules are even throughout a space

Electric Gradient

Is a spatial variation of both electrical potential and chemical concentration across a membrane.

Pressure Gradient

Is a physical quantity that describes in which direction and at what rate the pressure changes the most rapidly around a particular location.

Osmosis

 Is the movement of solvent molecules through a selectively-permeable membrane into a region of higher solute concentration, aiming to equalize the solute concentrations on the two sides.

Hypotonic Solution

 Is the same as the solute concentration of another solution with which it is compared.

Hypertonic Solution

 Is a solution having a lesser solute concentration than the cytosol.

Isotonic Solution

 Solutions that have equal osmotic pressure, such as the isotonic environment.

Hydrostatic Pressure

 Is the pressure exerted by a fluid at equilibrium due to the force of gravity.

Osmotic Pressure

Is the pressure which needs to be applied to a solution to prevent the inward flow of water across a semipermeable membrane.

Endocytosis

A small patch of plasma menbrane balloons inward and pinchesoff inside the cytoplasm.

Exocytosis

A vesicle moves to the cell surface, and then the protein-studded lipid bilayer of  its menbrane.

Phagocytosis

 ("cell eating")

Cell Structure and Function

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-soulable substances across it .

Wavelenght : 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 , wich cannot be diffracted through a glass lenses.

Transmission Electrons Microscope : electron pass through a specimen and are used to make images of its internal detail.

Scanning electron microscope : direct a beam of electrons back and forth across a surface of specimen , which has been given a thin metal coating.

Organelles : membrane bounded sacs.

Secretory Pathway : moves new polypeptide chains from some ribosomes through ER and golgi bodies , the on to the plasma membrane for release from the cell.

Endocytic Pathway : moves ions and molecules into the cytoplasm .

Vesicles : move substances from one organelle to the next in line .

Nuclear envelope : is a 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 and its associated proteins , regardless of whether it is in dispersed or condensed form.

Peroxisomes : hold enzymes that digest fatty acids, amino acids , and hydrogen peroxide , a toxic metabolic product.

Cell Junction : are molecular structures where a cell sends or receives signals or materials , or recognizes and glues itself to cells of the same type.

Basal body : microtubules into the 9+2 array, then it remains below the finish array.

Pseudopods : False feet.