Cell Membrane and Function Flashcards
Why do phospholipids form a bilayer
the hydrophobic tails buried in the interior of the membrane and the polar head groups exposed on both sides, in contact with water
process of simple diffusion
molecules pass between the phospholipids to enter or leave the cell, moving from areas of high concentration to areas of low concentration
process of facilitated diffusion
molecules diffuse across the plasma membrane with assistance from membrane proteins, such as channels and carriers.
process of osmosis
the movement of molecules from a region of higher concentration to lower concentration until the concentrations become equal on either side of the membrane.
do molecules move down or up in the concentration gradient in passive transport?
down a concentration gradient, meaning they move from areas of high concentration toward areas of lower concentration.
do molecules move down or up in the concentration gradient in active transport?
against the concentration gradient, from an area of low concentration to an area of high concentration.
Is energy needed in passive transport?
no energy is necessary
is energy needed in active transport?
energy is necessary
What are some examples of passive transport
Simple Diffusion.
Facilitated Diffusion.
Filtration.
Osmosis
what are some examples of active transport?
Exocytosis.
Endocytosis; Pinocytosis & phagocytosis
describe the process of endocytosis
capturing a substance or particle from outside the cell by engulfing it with th e cell membr ane
describe the process of exocytosis
a process for moving large molecules out of the cell to the cell exterior.
define a hypotonic solution
Solutions that contain a lower concentration of water and solutes
define a isotonic solution
Solutions that contain the same concentration of water and solutes as the cell cytoplasm
define hypertonic solution
Solutions that contain a higher concentration of water and solutes as the cell cytoplasm
