Question | Answer |
Definintion of "plasma" | Something formed |
Definition of "lemma" from the word plasmalemma | Husk |
Another name for Plasma membrane | Cell membrane |
Glycocalyx | An external carbohydrate coat found on the plasma membrane |
Lipids | Materials that are insoluble in water-fats, oils, and steroids. (3 kinds in the plasma membrane) |
Phospholipids | Highest in number. Contain phosphate. And are polar. |
Hydophobic | Term used to describe the non-charged, water repelling tails of the phospholipids |
Hydrophilic | Term used to describe the charged, water loving head of the phospholipids. |
Phospholipid bilayer | Formed because of the way the charged and non charged ends of the phospholipids associate w/eachother. |
Intracellular fluid ICF | Fluid within the cell |
Extracellular fluid ECF | Fluid outside the cell |
Cholesterol | Type of lipid called a steroid. Also amounts to about 20% of plasma membrane lipids |
Located in the bilayer. Strenghtens the membrane and stabilizes membrane at temp extremes | Cholestrol |
Glycolipids | Make up about 5-10% of all lipids. Located only on the outer layer. Involved in intracellular adhesion, and cell to cell recognition and communications |
Proteins | Complex diverse molecules composed of chains of smaller molecules called amino acids |
Make up about 1/2 the plasma membrane by weight. And is responsible for most of the membrane's specific functions. | Protiens |
Integral proteins | These are embedded within, and extend across, the phospholipid bilayer |
These act ac membrane channels, providing a pore through which specific substances pass | Integral proteins |
Receptors | Serves as binding sites for molecules outside the cell. |
Integral proteins are similiar to phospholipids in that they- | Have hydrophobic and hydrophillic regions. |
Perifpheral proteins | Are attached loosely to either the external or internal surface of the membrane. They float about the bilayer. |
Enzymes | Both integral and peripheral proteins may serve as catalysts and are known by this term. |
Change the rate of a metabolic reaction without being affected by the reaction itself. | Enzymes |
Glycoproteins | An integral protein with an attached carbohydrate group. |
This type of protein together with another type of lipid form the fuzzy glycocalyx on external surface of the plasma membrane. | Glycoproteins |
ATP | Adenosine triphosphate |
Function of ATP | Provides energy for some transports by releasing energy when the third bond in the molecule is broken. |
This function of the plasma proteins is responsible for junctions that form btwn some neighboring cells when proteins in the membranes attach. | Intercellular connection |
This function of the plasma proteins maintains the cell shape by the attachment of structural proteins inside the cell. | Anchor for the cytoskelton |
This function of plasma proteins is the catalyst that changes metaboli rates of reactions. | Enzyme activity |
This function of plasma proteins has carb components of glycoproteins and glycolipids that aid in _____. | Cell to cell recognition. |
This is a plasma protein function that sends messages from a molecule outside the cell to a molecule inside the cell. | Signal transduction |
Factors that influence membrane permeability-these _____ bind to specific carbs and helps them move across the membrane. | Transport proteins |
Factors that influence membrane permeability-______ differs which enables some molecules to cross the bilayer and others to not pass. | Plasma membrane structure |
Factors that influence membrane permeability-Materials tend to move more rapidly when their ______ is signficicantly different btwn the two compartments. | Concentration gradient |
Factors that influence membrane permeability-
Permeability depends on the ______, which determines attractiveness. | Ionic charge |
Factors that influence membrane permeability-Materials that are ______ easily disovlve to pass through the bilayer. ex, nonpolar fatty acids. Whereas, complex sugars are non_______, and do not pass through. | Lipid soluble (solubility) |
Factors that influence membrane permeability-Some molecules and ions move continuosly across the bilayer because of _____. | Molecular size |
Concentration Gadient | The flow of materials from a region of higher concentration to a region of lower concentration. |
Passive transport processes include: | Osmosis, simple diffusion, Facilitated diffusion, and bulk filtration. |
Factors influencing membrane permeability: | Transport proteins, Plasma membrane structure, Concentration gradient, ionic charge, lipid solubilty, and molecular size. |
Definition of Diffusion | To pour in different directions |
Simple diffusion: | The tendency of molecules to move down their concentration gradient. |
Equilibrium: | A point where the concentration gradient no longer exhists. |
Net movement: | A result of the concentration gradient, and coninues until molecules are evenly distributed. |
Osmosis: | Simple diffusion in which WATER diffuses from one side of the selectivlely permeable membrane to the other, continues until equilibrium is established. |
Facilitated diffusion: | Requires a specific transport protein to help certain large molecules and nonlipid soluble molecules cross the bilayer. |
How facilitated diffusion occurs. | By binding the molecules to the transport protein, which alters the size and shape of both, allowing molecules to pass |
Hydrostatic pressure: | Fluid pressure exerted by blood pushing against the inside wall of a blood vessel |
Bulk filtration: | Involves the diffusion of solvents and solutes together. |
Solutes: | Liquids that have solutes disolved in them. |
How bulk filtration works. | When hydrostatic pressure forces water ans small solutes from the blood across the plasma membranes th |
Active transport: | The movement of a substance across a plasma membrane against the concentration gradient. |
Types of Active transport: | ion pumps and Bulk transport |
Ion pumps: | Active transport process that moves ions across the membrand. |
Sodium-potassium pump: | Moves one ion into the cell while removing another type of ion from the cell. |
Some human cells require,or have, higher concentrations of potassium and lower sodium. What process is used to maintain this steep concentration gradient. | Sodium-potassium pump |
Bulk transport: | Occurs because/when macromolecules (large proteins) and polysaccharides cannot move across the plasma membrane. |
Exocytosis: | Large molecules are secreted from the cell. |
How exocytosis occurs | When vesicles and plasma membrane come into contact; and lipid molecules from the vesicle and the bilayers rearrange to fuse. The macromolecule is then released to the outside of the cell. This process requires the use of ATP. |
Endocytosis: | Large paticulate substances and macromolecules are taken into the cell |
How endocytosis occurs | Extracellualr macromolecules and large particulates are packed in a vesicle that forms at the cell surface, a pocket is formed then the bilayer fuses, forming a new vesicle containing the material to be brought into the cell. |
types of bulk transport: | exocytosis, endocytosis: phagocytosis, pinocytosis, receptor-mediated endocytosis |
Invagination: | A small area of plasma membrane folds inward to form a pocket. |
Phagocytosis: | Cellular eating |
Psuedopodia: | A membrane extension formed during phagocytosis. |
How phagocytosis occurs | When a cell engulfs an external particle then membrane extensions are formed and particle is packaged within. Contents then digested after fusion w/a lysome |
Pinocytosis: | Cellular drinking |
How pinocytosis occurs: | Occurs when the cell internalizes small droplet of extracellular fluid into tiny vesicles. This process is non specific because all solutes are dissolved and taken in by the cell. |
Receptor-mediated endocytosis: | The movement of specific molecules from teh extracellular environment into a cell by way of anewly formed vesicle. |
How receptor-mediated endocytosis occurs | This is a specific mechanism. the Endocytosis is stimulated by binding of specific molecules to their specific membrane receptors. A pocket is formed, then pinced off, bilayer fuses, then incoming molecule is taken into the cell. ATP is used. |
Example of receptor-mediated endocytosis | Cholestrol bound proteins called LDL receptors(low-density lipoproteins) |
Example of pinocytosis | Cells from capillary wall, vesicles fill w/fluid containing solutes from blood, then carry it to other side of cell then expel its contents outside the capillary wall |
Example of phagocytosis | White blood cell engulfs and digests a bacterium |
Example of Simple diffusion | Oxygen continually moves from the lung air sacs into the blood, while carbon dioxide moves in the opposite direction |