Cell Membrane And Membrane Transport Mechanisms

Front 1

plasma membrane

Back 1

a fluid structure which functions as the cell's protective boundary

Front 2

integral proteins

Back 2

transmembrane proteins: embedded in the lipid layer for mainly transport functions

Front 3

peripheral proteins

Back 3

found on the inside or outside of cell membrane.

Front 4

glycocalyx

Back 4

coating on outside of cell membrane. functions are anchoring, locomotion, lubrication, and recognition.

Front 5

MHC protein

Back 5

major histocompatablity complex. "cellular ID card"

Front 6

diffusion

Back 6

molecular movement of solutes. direction of movement is determined by the concentration of solute. Always moves from high to low.

Front 7

rate of diffusion depends on

Back 7

1. size of gradient
2. size of molecule
3. charge
4. lipid solubility
5. temperature

Front 8

simple diffusion

Back 8

diffusion without the use of a membrane channel. molecules that can travel through a membrane without membrane channels are lipid soluble compounds (alcohols, fatty acids, steroids, O2, CO2)

Front 9

osmosis

Back 9

movement of water molecules from a higher concentration to a lower concentration across a semipermiable membrane.

Front 10

factors affecting the rate of osmosis

Back 10

1. concentration gradient
2. opposing osmotic or hydrostatic pressure

Front 11

osmotic pressure

Back 11

force of water movement into the solution of higher solute concentrations.

Front 12

hydrostatic pressure

Back 12

opposes osmotic pressure. the heart generates hydrostatic pressure by pushing blood and its components into tissues of the body.

Front 13

examples of hydrostatic pressure

Back 13

gravity
heart pumping
blood pressure

Front 14

tonicity

Back 14

the ability of a solution to change the tone or shape of a cell by altering their internal water volume

Front 15

isontonic

Back 15

solution with concentrations of nonpenetrating solutes equal to those found in cells (.9% saline or 5% glucose) cell retains normal shape

Front 16

hypotonic

Back 16

more dilute solution, lower concentration of nonpenetrating solutes. cells will swell and burst as water rushes in.

Front 17

hemolysis

Back 17

RBC's bursting

Front 18

hypertonic

Back 18

solutions that contain a higher concentration of nonpenetrating solutes. when a cell is immersed in such solutions it will lose water causing it to shrink.

Front 19

crenation

Back 19

RBC's shrinking

Front 20

filtration

Back 20

movement of water usually with solute by hydrostatic pressure or gravity. requires a filtration membrane. important in kidney function.

Front 21

facilitated diffusion

Back 21

carrier proteins passively transport solutes across a membrane gradient. facilitated diffusion is needed when the molecules are lipid insoluble or too large to pass through the lipid membrane. glucose and AA's can be transported this way.

Front 22

carrier proteins

Back 22

integral proteins that can carry substances through membranes. facilitated diffusion is limited by number of carrier proteins available. if saturated then no more can be transported.

Front 23

active transport

Back 23

carrier proteins actively (use ATP) transport solutes across a membrane regardless of concentration gradient.

Front 24

factors affecting rate of active transport

Back 24

availablity of carrier protein
availability of substance
enzyme to cleave ATP

Front 25

substances involved in active transport

Back 25

Na, K, Ca, Mg (all cells)
other substances by specialized cell.

Front 26

K and Na in cells and interstitial fluid.

Back 26

cell is high in K and low in Na
interstitial fluid is low in K and high in Na.

Front 27

for every ATP cleaved ___intracellular Na get pumped out while ___ extracellular K get pumped in.

Back 27

3,2
Na-K exchange pump

Front 28

secondary active transport

Back 28

two solutes are cotransported (glucose or AA riding in with the diffusion force of sodium) or counter transported (sodium in and calcium out) at the same time. the diffusion gradient of one solute drives the second solute through. Now the cell needs an active solute pump to correct for all the extra solute coming into the cell

Front 29

vesicular transport

Back 29

material move in and out of the cell by little vesicles. large volumes of materials can be packaged and transported this way.

Front 30

endocytosis

Back 30

bulk transport into a cell. creation of a membranous vesicle containing fluid or solid material.

Front 31

receptor mediated endocytosis

Back 31

receptors on membrane's surface bind to specific ligands. bond receptors cluster together. a vesicle is formed and endocytosed to become an endosome or coated vesicle.

Front 32

phagocytosis

Back 32

cell eating

Front 33

pseudopodia

Back 33

cytosplasmic extentions that engulf extracellular mass.

Front 34

pinocytosis

Back 34

cell drinking

Front 35

exocytosis

Back 35

fusion of vesicles containing fluids and/ or solids within the cell membrane to the cell membrane and exporting vesicle contents outside of the cell (secretion)

Front 36

transmembrane potential

Back 36

slight charge differences between inside the cell membrane (-) and outside the cell membrane (+). the influx and outflow of ions via active transport mechanisms and selective cell membrane permiability cause these charge differences.

Front 37

potential difference

Back 37

positive and negative charges are held apart or polarized.

Front 38

transmembrane difference

Back 38

potential difference across a cell membrane.

Front 39

resting potential

Back 39

transmembrane potential of a resting cell. each cell has a naturally negative characteristic resting potential
the greater the resting potential of a cell the greater the ability of that cell to do work.

Front 40

characteristics of polarization

Back 40

when charges are separated across the cell membrane- polarized
when charges mix (influx of Na)- depolarized
Na-K exchange pump- repolarized