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Anatomy & Physiology Exam 1
Cellular Transport Mechanisms
20
Anatomy
Undergraduate 2
02/11/2010

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Cards

Term
What are the types of cellular transport?
Definition

Passive and Active

 

1) passive - facilitated diffusion, osmosis, simple diffusion

2) active - primary active trasnsport (Na+/K+ ATPase pump)

Term

passive transport

movement of what?

concentration gradient?

Definition

does not require ATP

-movement of solutes from an area of HIGHER concentration to LOWER 

-move DOWN a concentration gradient

Term

simple diffusion

rate of diffusion with temperature?

rate of diffusion with molecular size?

Definition

type of passive transport

 

-rate of diffusion INCREASES as temp. INCREASES

-rate of diffusion DECREASES as molecule size INCREASES

Term

facilitated diffusion

 

Definition

type of passive transport

-diffusing substance binds with CARRIER protein on the inner or outer surface of plasma protein)

-binding causes a conformational change in carrier protein: it flips upside down

-after changes, substance is then released into intra/extracellular fluid

Term

Osmosis

terms of solutions across a membrane?

Definition

type of passive transport

 

-the movement of WATER from an area where there are LESS solutes to where there are MORE solutes.

-terms: hypertonic, hypotonic, isotonic

 

Term
hypertonic
Definition
the solution with more solutes "more salt"
Term

hypotonic

how does water move?

Definition

the solution with less solute particles

-water will always move from a hypotonic solution to a hypertonic solution

Term
suppose a cell with 5 g NaCl is dropped into a beaker containing 15 g NaCl. Which solution is hypertonic? hypotonic? where will water go?
Definition

-beaker is hypertonic

-cell is hypotonic

-water will move out of the cell into the beaker

-cell will shrink (crenate)

Term
in facilitated diffusion, what type of proteins are used as carrier proteins?
Definition
peripheral
Term

Suppose a cell with 11 g NaCl is dropped into a beaker that contains 11 g NaCl. 

Which solution is hypertonic?

hypotonic?

where will water go?

Definition

-the 2 solutions are isotonic

-no osmosis will occur, no movement of water

Term

Active transport

concentration gradient?

Definition

requires ATP and involves movement of solutes from an area of LOWER concentration to HIGHER

 

-solutes move UP or AGAINST the concentration gradient

Term
How does the K+/Na+ ATpase pump move the ions against their concentration gradient?
Definition

through energy derived from enzymatically splitting ATP into ADP and an inorganic phosphate group

 

-this splitting releases energy

Term

There is there more Na+? k+?

Where does the pump move them? how many?

Definition

More Na+ outside the cell and more K+ inside the cell

-the pump moves 3Na+ outside the cell toward a HIGHER Na+ concentration

-the pump moves 2K+ inside the cell toward a higher K+ concentration

Term
membrane potential
Definition

the generation of "voltage" (energy) in the form of electricity by the separation of oppositely charged particles across the membrane

 

 

Term

resting membrane potential

what is the usual RMP?

why is this value negative?

Definition

the charge on an excitable nerve/muscle cell's membrane when it is at REST (inactive)


-90 mv to -70 mv 

-negative because the intracellular fluid is more negative than extracellular fluid

 

Term
At rest, is the cell polarized or non-polarized?
Definition
polarized (due to separation of charges)
Term
Why is the inside of the cell negative?
Definition

1) at rest, the membrane is more permeable to K+ than to Na+

2) due to large concentration of intracellular negatively charged proteins that are IMPERMEABLE

3) lots of K+ moves passively out of cell because of its ion channel, taking the + with it

Term
At rest, where does the Na+ go?
Definition
a little Na+ moves passively into cell because of its ion channel (but not as much as K+ leaves cell)
Term
How is K+ and Na+ kept at an equilibrium?
Definition
the passive and active movements occur simultaneously (at the same time)
Term
What are the 3 main roles of the Na+/k+ ATPase pump?
Definition

1) actively kicks some Na+ out of cell

2) actively pulls some in K+ to inside the cell

3) maintains differential concentration gradients for Na+ and K+ (they STORE ENERGY for nerve and muscle cell formation)

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