Cell Transport

pre and post

These things can move through biological membranes without any help

small and or hydrophobic molecules

These things cannot move through biological membranes on their own without help.

large and or hydrophilic molecules

Tonicity is a comparison of the solute levels of two locations. (blank) means that the two locations are equal in solute concentration.

Isotonic

identifies the location that has the higher solute level

Hypertonic

identifies the location that has the lower solute level.

Hypotonic

Choose all of the following terms and concepts that are associated with Active Transport.

Needs an energy source - endergonic. Carrier proteins called pumps. Movement from low gradient to high gradient

Choose all of the following that can be true of the movement (transport) of water.

Water travels using osmosis. Water will move from a hypotonic area to a hypertonic area. Water can move through aquaporin channels - a type of facilitated diffusion. Water can only move from high concentration to low concentration.

K+

-94mV 

Ca2+

+135 mV

Cl-

-88 mV

Na+

+60 mV

Which of the following are found at relatively higher concentrations in the ECF?  Choose all that apply.

Ca2+, Na+, Cl-, Mg2+, HCO3- (bicarbonate)

Considering the Nernst equation, which of the following are true?  Choose all that apply.

z is the charge of the ion, The Nernst equation calculated the point of equilibrium for a particular ion which means the point at which the chemical and electrical gradients are both equal and opposite, The symbol E denotes the equilibrium potential.

The major constituent of the cell membrane, they are amphipathic molecules

phospholipids

A steroid that acts to help maintain the fluidity of the cell's membrane

cholesterol

A measurement of the solute concentration inside and/or outside of a cell

tonicity and osmolarity

The Diffusion of water from high concentration to low concentration

osmosis

Transmembrane protein(s) that act to form a tunnel in the membrane. Some of these have one or more gates

channels

Transmembrane protein(s) that change their shape to move a substance across the membrane

carriers 

The use of membrane bound vesicles to move a substance either into or out of the cell

bulk transport

The movement of a large and/or hydrophilic substance against its gradient using an ATPase carrier to do it

primary/direct active transport

The movement of a substance through the membrane, with a carrier protein, against its gradient using the energy provided by an ion moving with its gradient

secondary/indirect active transport

The movement of a substance through the cell's membrane, without any protein assistance, with its gradient

simple diffusion

The movement of a substance with its gradient through the cell's membrane with the assistance of either a protein carrier or channel

facilitated diffusion

A vesicle engulfing a substance on one side of an epithelial layer and being trasported through the cell and being dumped out of the vesicle on the other side

transcytosis

The movement of a substance through an epithelial cell layer - through the cell itself - without the use of a vesicle for transport

transcellular movement 

The movement of a substance around the cells of an epithelial layer - outside of the cells themselves

paracellular movement

The amino acid Valine is an uncharged (nonpolar) amino acid.  If it is at a relatively high concentration in the ICF and a low concentration in the ECF what transport would the cell have to use if it wanted to move valine from the ECF to the ICF?

Secondary Active Transport

If you have an "average" cell, the direction of the chemical force on K+ in that cell is

from the ICF to the ECF

In this same cell, the direction of the electrical force in that cell is

from the ECF to the ICF

The direction and magnitude of the electrochemical gradient for K+ in this same cell would be

24 mV from the ICF to the ECF

If you had another cell whose Vm = +30 mV, the vector for Ca2+ would be

105 mV from ECF to ICF

The concentration of glucose in the lumen of the duodenum is 1300 mM

The concentration of glucose in the epithelial ICF is 50 mM

The concentration of glucose in the blood is 150 mM.

If you moved one molecule of glucose from the lumen to the ICF your cell would use

facilitated diffusion 

This movement is across the (blank) membrane of the epithelial cell.

apical

Now that one glucose molecule is inside of the cell, the cell would then need to use

secondary active transport

This movement is across the (blank) membrane of the epithelial cell.

basolateral