ch 3 plasma membrane and membrane potential

What are the main components of a cell membrane?

phospholipids embedded w proteins, small amt of carbs and cholesterols

What is one function of the cell membrane?

Controls movement of molecules between the cell and its environment

What are the main components of a cell membrane?

phospholipids embedded w proteins, small amt of carbs and cholesterols

What is one function of the cell membrane?

Controls movement of molecules between the cell and its environment

How does the cell membrane contribute to tissue formation?

It joins cells to form tissues and organs

What role does the cell membrane play in environmental response?

It plays an important role in the ability of a cell to respond to changes in the environment

cell membrane proteins

attached to or inserted wi the bilayer that form channels, serve as carrier molecules, docking marker acceptors, membrane bound enzymes, receptor sites, cell adhesion molecules, and recognize self

function of lipid bilayer

structure, hydrophillic barrier, fluidity

membrane carbohydrates

serve as self identity markers

cell to cell adhesions

bind cells into tissues and package them into organs.

extracellular matrix

biological glue, has collagen, elastin, fibronectin,

Specialized cell junctions

desmosoms, tight junctions, gap junctions

Desmosomes

Anchoring junctions that prevent cells from being pulled apart

tight junctions

firmly bond, seal off the passageway bw two cells, found in epithelial tissue, stops leaks

gap junctions

small connecting tunnels formed by connexons, cardiac and amooth musce, permits unrestricted passage of small nutrients bw cells, serves as a method of direct transfer of small signaling molecules from one cell to the next

unassisted membrane transport

diffusion and osmosis

assisted membrane transport

Carrier-mediated transport

Facilitated transport

Active transport

diffusion

high to low, found in exchange of o2 and co2, movement of substances across kidney tubules

ficks law of diffusion

diffusion through a membrane is directly proportional to the surface area and concentration gradient and inversely proportional to the thickness of the membrane and its resistance

osmosis

net diffusion of water down its own concentration gradient

isotonic

when the concentration of two solutions is the same

hypotonic

Having a lower concentration of solute than another solution

hypertonic

Having a higher concentration of solute than another solution.

carrier mediated transport

The type of transport in which proteins bind to ions or substrates and carry them across the plasma membrane

assisted membrane transport

facilitated diffusion, active transport, vesicular transport

facilitated diffusion

high to low, uses a carrier molecule, how glucose travels

Active transport

against concentration gradient, uses carrier molecule

primary active transport

requires direct use of ATP

secondary active transport

Form of active transport which does not use ATP as an energy source; rather, transport is coupled to ion diffusion down a concentration gradient established by primary active transport.

vesicular transport

material moves in/out of cell wrapped in membrane, endo and exocytosis

endocytosis

substances move into cell

pinocytosis

nonselctive uptake of ecf

phagocytosis

selective uptake of multimolecular particle

exocytosis

mechanism to secrete large polar molecules, enables cell to add specific comp to membrane

membrane potential

The voltage across a cell's plasma membrane, sep of opp charges across a plasma membrane, due to diff in concentration and permeability of key ions

nerve and muscle cells

are excitable aka they can make rapid changes in their membrane potential when excited

resting membrane potential

the constant membrane potential of both excitable and non excitable at rest