membrane transport/osmolarity/tonicity/osmotic pressure

list 2 molecules that move through a cell membrane by simple diffusion

oxygen & carbon dioxide

list 2 molecules that move through a cell membrane by facilitate diffusion

glucose & amino acids

List one molecule that moves through a cell membrane through aquaporin

water

What factors can influence the rate the diffusion?

temperature, surface area, distance, size of molecule

Diffusion

the movement of a substance from an area of high concentration to an area of low concentration

In simple diffusion, the GREATEST net movement of a substance across a membrane will occur if…

the available surface area is large

______ is the transport of a substance through the membrane by a protein CARRIER and this type of transport requieres NO ENERGY input by the cell

facilitated diffusion

Diffusion is important to body fluids because it tends to….

eliminates local concentration gradients

what can freely diffuse through the plasma membrane

non-charged & hydrophobic molecules

faciliated diffusion differs from regular diffusion in that…

the rate of molecular movement is limited by the number of available carrier molecules

The phospholipid bilayer is…

composed of 2 layers of phospholipids oriented so that the head groups point to the intracellular and extracellular fluid

The Na+/K+ ATPase (pump) moves____into the cell and _____out of the cell

K+ & Na+

The movement of an amino acid from an area of its high concentration to an area of its low concentration would most likely be…

facilitate diffusion

What is the Na+/K+ATPase involved in?

active transport

Define enzyme

catalyze chemical reactions (speed up)

Na+/K+ATPase (ion pump) is an enzyme because…

it speeds up hydrolysis of ATP

Cell membrane (plasma membrane) are composed of..

phospholipids (proteins) & cholesterol

The 4 functions of the cell membrane

1. physical isolation

2. regulate exchange w/environment

3. sensitive to environment

4. structural support

glycocalyx

carbohydrate coat on OUTSIDE of cells

4 functions of glycocalyx

• protection & lubrication

• locomotion & anchor/binding

• specifity in receptor

• recognize self from non-self

Passive diffusion

• NO ENERGY required

• includes simple diffusion, osmosis, and facilitated diffusion

what substances can diffuse across the membrane

water, oxygen, carbon dioxide, and lipid soluable substances

Osmosis

diffusion of WATER across cell membrane

How does water move?

from an area of low conc to an area of high conc; water will move towards solution with more solute

How do substance in simple diffusion and facilitated diffusion move?

area of high conc to low conc

facilitaed diffusion

• for large molecules

• can transport more than one particle at a time

• used for glucose and amino acids

• requires concentration gradient

osmotic pressure

• force of water movement into solution as result of solute concentration

• water moves towards HIGH______

osmotic pressure

low solute conc=low osmotic pressure

high solute conc=high osmotic pressure

osmolarity

molarity multiplied by number of particles

tonicity

• refers to solution

• describes the movement of water

• isotonic, hypotonic, hypertonic

isotonic

solution concentration outside of cell is equal to solute concentration inside the cell

hypotonic

A greater concentration of solutes inside the cell than outside the cell

hypertonic

a greater concentration of solutes of outside the cell then inside

hypotonic

hemolysis (swelling) of the cell

hypertonic

shrinking of the cell

Active transport

• uses ENERGY (ATP) to move against the conc. gradient

• requires specific carrier molecules

exocytosis

• requires ATP

• move something out of the cell

endocytosis

• moving something inside the cell by engulfment

• phagocytosis, pinocytosis, receptor mediated

Phagocytosis

cell eating; solid into the cell

Pinocytosis

cell drinking; liquid into the cell

receptor mediated

materials bind to surface receptor —> receptors cluster —> membrane pinches inward —> endocytosis of receptor bound compounds