Term
|
Definition
- transport method
- passive movement of substances down their concentration gradient from an area of high concentration to low
- requires no energy
|
|
|
Term
|
Definition
- transport method
- energy is required
- substances move from a region of low concentration into a region of higher concentration
|
|
|
Term
|
Definition
- Form of diffusion that does not involve membrane proteins
- Other than carbon dioxide and oxygen, only lipids can cross the membrane by simple diffusion
|
|
|
Term
|
Definition
- chemicals that are not lipid-soluble move down their concentration gradients by this
- their transport is facilitated by the integral membrane proteins
|
|
|
Term
|
Definition
- watery tunnels through the cell membrane
- have different shapes, which permit the passage of specific substances
|
|
|
Term
|
Definition
- other substances, most importantly glucose, diffuse across the membrane through these
- only allow passage of specific solutes
- they change shape in order to enable transport
|
|
|
Term
|
Definition
- the movement of water across a semipermeable membrane from the area of low solute osmolarity to an area of higher solute osmularity
- changes the volume of a solution, and in confined spaces volume changes change the pressure
|
|
|
Term
|
Definition
- Have a greater solute concentration than the intracellular fluid, which means that the water concentration is higher inside the cell than outside
- cells placed in a hypertonic solution will lose water and shrink, because water will exit the cell into the solution
|
|
|
Term
|
Definition
- just right
- the solute concentration is equivalent between the solution and the cell, and the cell volume will stay the same
- cells placed in isotonic solutions neither gain nor lose water by osmosis
|
|
|
Term
|
Definition
- have lower solute concentration than the intracellular fluid, which means that water is in higher concentration ourside the cell than inside.
|
|
|
Term
|
Definition
- literally meaning, "out of a cell"
- method by which a cell expels material in bulk
|
|
|
Term
|
Definition
- literally meaning, into a cell
- begins as the cell membrane bulges inward
- the membrane fuses and closes around a trapped substance, forming a vesicle in which the substance is enclosed in a sac of cell membrane
- The vesicle then emerges with lysosome, whose enzymes digest the sac's contents.
|
|
|
Term
|
Definition
- some cells combine endocytosis and exocytosis to move substances across the cell
- endocytosis brings the substance into the cell, which is subsequently transferred to another vesicle for exocytosis.
- example: HIV, and herpes
|
|
|
