Chapter 4 Part 2: Osmosis Flashcards
Define diffusion.
The spontaneous movement of a substance from a region where it is more concentrated to a region where it is less concentrated .
Define concentration gradient.
A solute is more concentrated in one region than in a neighboring region.
What factors affect the rate of simple diffusion?
Temperature, size of molecule, type of medium.
How do cells maintain concentration gradients?
By consuming the substance as they diffuse or by producing more of the substance as they diffuse out.
Define osmosis.
Simple diffusion of water across a selectively permeable membrane.
What factors affect the rate of osmosis?
Temperature, because a faster temperature a faster reaction.
the distance the molecules have to move across, so the more distance between the two sides the slow the rate of osmosis.
Concentration of water potential and lower water potential sides
Define turgor pressure?
It is the resulting force of water against the cell wall.
Compare diffusion and osmosis.
Diffusion is the spontaneous movement of a substance from a region where it is more concentrated to a region where it is less concentrated. Osmosis is the simple diffusion of water across a selectively permeable membrane . Both move across water.
Define facilitated diffusion.
It is a form of passive transport in which a membrane protein assists the movement of a polar solute along its concentration gradient.
Define active transport.
Transport protein moves substances against its concentration gradient; requires energy input, often from ATP.
Compare active transport and facilitated diffusion.
Facilitated diffusion is substances to which the membrane is not permeable across the membrane with assistance of transport proteins.
Active transport is transport protein moves substances against its concentration gradient requires energy input, often from ATP.
They both use proteins to transport substances.
Define endocytosis.
Allows cells to engulf fluids and large molecules and bring them into the cell.
Define phagocytosis?
The cell captures and engulfs large particles, such as debris or even another cell.
Define Exocytosis.
The opposite of endocytosis, uses vesicles to transport fluids and large particles out of cells.
Explain how the sodium-potassium pump is important to the normal functioning of the cell.
This pump is a protein embedded in the cell membrane. It uses energy released in ATP hydrolysis to move potassium ions into the cell. In each case, the ions move from where they are less concentrated to where they are more concentrated.
How do plant cells keep their shapes?
By regulating diffusion
What are the type of cell junctions?
Tight junction fuses cells together, forming an impermeable barrier between them.
Anchoring junction connects adjacent cells by linking their intermediate filaments in one spot.
Gap junction is a protein channel that links the cytoplasm of adjacent cells, allowing of exchange of ions, nutrients, and other small molecules.
What is non competitive inhibition?
A substrate binds to an enzyme in a place other than the active site, changing the shape of the protein.
What is a competitive inhibitor?
Physically blocks the active site of an enzyme.
What factors affect the rate of active transport?
Concentration of oxygen, concentration of glucose temperature. Surface area also affects.
How are vesicles used in endocytosis and Exocytosis?
In endocytosis the vesicles traps whatever was outside the membrane. Then brings the particles in the cell. Then the vesicles surrounds the imported particles.
In Exocytosis the vesicles surrounds the particles to be exported. Then the vesicles moves to the cell membrane. And then the vesicles merges with the membrane releasing particles to the outside.
What is Exocytosis?
Uses vesicles to transport fluids and large particles out of the cell.
