Chapter 6 Flashcards
what do cell membranes define?
the boundary of the cell
why are cell membranes considered fluid?
because the structure is not fixed and lets molecules in and out
why are cell membranes considered mosaic?
because they have different protein molecules embedded
cell membranes are made up primarily of what?
a bilayer of phospholipids
cell membranes are made up of mostly a bilayer of phospholipids with what?
embedded proteins, carbohydrates, glycolipids, glycoproteins, and cholesterol
is there cholesterol in the cell membrane of plants?
no, just animals
what are the two types of transport?
passive and active transport
does passive transport require atp for molecule movement?
no
does active transport require atp for molecule movement?
yes
in passive transport, molecules move…
from higher concentration to lower concentration
in active transport, molecules move…
against the gradient
the most direct forms of naturally occuring transport?
passive transport
membranes have hydropholic and hydrophobic regions, what does this do?
it helps the transport of some materials and hinders that of others
what kind of material can slip easily through the hydrophobic lipid core of the cell membrane?
lipid-soluble material
what are some examples of passive transport?
diffusion, facilitated diffusion, and osmosis
what is diffusion?
a material moves from an area with a high concentration to an area with low concentration until concentration is equal across the area
what is facilitated transport?
materials diffuse across the plasma membrane with the help of membrane proteins
does facilitated transport require energy?
no
does facilitated transport require concentration?
yes
what are transport proteins?
integral proteins involved in facilitated transport
what is osmosis?
a special type of diffusion of water from a higher concentration to a lower one through a semipermeable membrane
what does tonicity mean?
how an extracellular solution can affect the volume of the cell by affecting osmosis
what does hypotonic mean?
this means that the extracellular solution has a lower concentration of solutes
what does hypertonic mean?
this means that the extracellular solution has a higher concentration of solutes
what does isotonic mean?
this means that the extracellular solution has the same concentration as the cell’s cytoplasm
what form of energy does active transport typically use?
adenosine triphosphate, atp
ions move in and out of the cell membrane and proteins that do not move across the cell membrane are negatively charged. What happens as a result of this?
an electrical gradient, a difference of charge across the plasma membrane
what is the electrochemical gradient?
the combined gradient of concentration and electrical charge that affects an ion
what are some types of endocytosis?
pinocytosis, phagocytosis, and receptor-mediated endocytosis
what is endocytosis?
a type of active transport that moves large particles into the cell
what is the common characteristic that all types of endocytosis share?
the plasma membrane forms a pocket for the target particle then envelopes it in it.
what is phagocytosis?
the process by which large particles are taken in by the cell
what is pinocytosis?
the process by which cells take in molecules, including water, from extracellular fluid
what is another name for pinocytosis?
cell drinking
what is receptor-mediated endocytosis?
a type of endocytosis that employs receptor proteins in the plasma membrane that have a specific binding affinity for certain substances
what is exocytosis?
the opposite of endocytosis, expels material from the cell into the extracellular fluid
