Cellular Transport

Question	Answer
Semi-permeable Membrane	regulates substances permitted to enter cell
Concentration Gradient	difference between concentration inside the membrane and outside the membrane
Passive Transport	Processes to move substances from an area of high concentration to an area of low concentration in and out of the cell without an input of energy (diffusion, osmosis, and facilitated diffusion)
Diffusion	Net movement of ions from an area of high concentration to an area of low concentration (until concentrations in both areas are equal)
Factors Affecting Diffusion	-temperature (higher temp=more energy=faster rate of diffusion) -pressure(higher pressure=molecules forced to diffuse=increase rate of diffusion) -molecule polarity (polar molecules have it harder than non-polar molecules, so rate of diffusion is lower for polar molecules) -molecule charge (charged ions and molecules cannot diffuse across membrane) -molecule size (larger the size, rate of diffusion slows down as difficulty to diffuse increases)
Osmosis	Movement of water molecules, from an area of high concentration to an area of low concentration through a semi-permeable membrane
Hypotonic	Solution that has lower concentration (water enters the cell, and it might burst) (in plant cells, central vacuole fills, pressure increases and chloroplasts against cell wall)
Hypertonic	Solution that has higher concentration (water leaves the cell, and it shrivels (crenation)) (in plant cells, and central vacuole shrinks which leads to plasmolysis) if a solvent in continuously added outside a cell, the water will leave ie. fertilizer and roots of plant, dog pee
Isotonic	Both solutions have equal concentration of the substance (in animal cells, there is no net movement of water)
Lysis	Cell bursts (when there is more solvent in the cell than outside, then water goes in and bursts the cell)
Plasmolysis	Cytoplasm shrinks away from cell wall/membrane (ie. when there is more water inside the cell than outside, so water moves out of the cell and it shrivels up)
Facilitated Diffusion	A membrane protein assists diffusion along the concentration gradient (facilitated by proteins)
Channel Protein	-have hydrophilic interior -provides aqueous channel for specific molecules to cross membrane (ie. polar molecule) -tube, helix, gates Permit passage of ions or polar molecules Ie. sodium channel allows sodium ions to go across membrane
Carrier Proteins	-binds to and transports an ion or molecule(s) from outside of cell to inside of cell along concentration gradient -can change shape will transporting -sometimes more than one particle is transported therefore rate of diffusion usually lower compared to channels also perform active transport PACMAN
Details Carrier Proteins	Can transport larger molecules ie. glucose and amino acids Directional passage as tied to energy
Active Transport	transport of a solute across membrane AGAINST gradient, using a protein carrier that requires energy ie. ATP
Primary Active Transport	uses ATP directly to move molecules or ions from one side of membrane to the other (CARRIER PROTEIN)
Secondary Active Transport	uses electrical gradient as a source of energy to transport molecules across membrane
Primary Active Transport Details	Ie. ion pumps Sodium-potassium pump transports sodium out of cell, and transports potassium inside cell occurs against concentration gradient
Secondary Active Transport Details	*electrical gradient-combination of concentration gradient and electrical potential across membrane (stores energy that can be used by the cell) Ie. hydrogen-sucrose pump (hydrogen particles pumped out of cell, gradient by hydrogen ions allows sucrose ions to bind to carrier protein pump and go inside cell) AGAINST GRADIENT
Membrane Assisted Transport	process used to transfer too large molecules for membrane through carrier or channel protein
Endocytosis (vesicle formation)	Cell engulfs extracellular material by folding membrane around it, and then pinching to form a vesicle inside cell
Pinocytosis	Endocytosis involving liquid particles (Cell drinking)
Phagocytosis	Endocytosis involving solid particles (Cell eating) (ie. fragments of an organism)
Receptor mediated endocytosis	Use of receptor proteins on a portion of the membrane that bind with specific outside molecules (coated pit=that portion of the membrane, and this pit folds inward during endocytosis form a vesicle)
Exocytosis (vesicle fusion)	Exit of particles from membrane to the outer environment Vacuole joins membrane and releases its contents outside the cell (taking out the trash)
Exocytosis Examples	Means of secreting hormones, digestive enzymes (in intestines) and neurotransmitters Sebum that lubricates human skin

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	Created by gina_sweetangel0 about 8 years ago