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Mammalian Physiology 318 > Membrane Transport (1) > Flashcards

Membrane Transport (1) Flashcards

Exam 1

1
Q

How do cells communicate?

A

Cells communicate with each other by secreting chemical regulators into the extracellular environment

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2
Q

Cells receive nourishment from and release wastes into the ____ ____

A

extracellular environment

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3
Q

What does the extracellular environment include?

A

everything located outside the cells

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4
Q

What does body fluid refer to?

A

body fluid refers to the watery solution of dissolved substances (oxygen, nutrients, and wastes) present in the body

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5
Q

Intracellular Fluid Definition

A

fluid located inside the cells

~67% of all fluid in the body

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6
Q

Extracellular Fluid Definition

A

Fluid in the blood and in spaces surrounding the cells

remaining ~33%

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7
Q

What makes up extracellular fluid?

A

20-25% is in the fluid portion of blood (plasma)

75-80% lies around and between cells (interstitial fluid)

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8
Q

Interstitium Definition

A

space containing interstitial fluid

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9
Q

In membrane transport, what changes the conformation to move a molecule/ion?

A

carrier proteins

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10
Q

In membrane transport, what provides selective channels for the orient of specific substances (e.g., specific ions, water)?

A

Channel proteins

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11
Q

True or False:

The plasma membrane is selectively permeable

A

True

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12
Q

What are the two categories to enter membrane transport?

A
  1. Non-carrier mediated

2. Carrier mediated

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13
Q

What is non-carrier mediated?

A

simple diffusion, osmosis (filtration capillaries)

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14
Q

What type of transport happens in non-carrier mediated and what is the definition of that transport?

A

Active Transport- no energy, moved down gradient (high to low concentration)
Random molecular motion eventually evens things out

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15
Q

What type of transport occurs in carrier mediated and what is the definition of that transport?

A

Active Transport- against gradient (low to high concentration)
needs transport protein and ATP

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16
Q

Simple Diffusion Definition?

A

net movement of particles from high concentration to lower concentration
(down the gradients, spontaneous motion)

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17
Q

Does simple diffusion require a membrane?

A

No, simple diffusion does not require a membrane

if there is a membrane, substances will diffuse is the membrane in permeable

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18
Q

What are diffusion rates?

A

How quickly a cell can acquire or eliminate wastes

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19
Q

What factors effect simple diffusion rate through a membrane?

A
  • temperature (higher temp, faster particle motion)
  • molecular weight (larger molecular size, slower diffusion)
  • concentration gradient steepness (higher gradient, faster rate)
  • Membrane Surface Area (higher SA, faster rate-places like intestines/lungs/kidneys)
  • membrane permeability (higher permeability, faster rate)
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20
Q

Osmosis Definition

A

the net flow of water through a selectively permeable membrane

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21
Q

Osmosis moved from __ concentration to __ water concentration

A

high

low

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22
Q

What are aquaporins?

A

allows water to move across the membrane

  • -specialized channel proteins
  • -different by cell (install channels based on conditions)
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23
Q

What is osmotic pressure?

A

pressure required to stop osmosis

measure of how strongly a solution draws water

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24
Q

___ solute concentration the __ the pressure

A

greater

greater

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25
What is molarity?
number of molecules of solute per liter of a solution | same molecule number
26
Physiological impact of a chemical depends on how many ___ of it are present in a given ___
molecules | volume
27
How many molecules are in a mole?
6.022 x10^23 molecules in a mole
28
What is osmolarity?
the number of osmoles per liter of solution (the total number of solute particles (concentration) in a solution
29
one osmole (osm) = __ ___ of dissolved particle
1 mole
30
___ osmolarity = ___ water concentration
higher | lower
31
What is tonicity?
ability of a surrounding solution (bath) to affect fluid volume and pressure in a cell
32
concentration of ___ vs ___ causes water to move in or out of a cell
solutes | water
33
Effect of osmosis on cells in isotonic solution
- no change in cell volume - concentrations of non permeating solutes in bath of ICF are the same - 0.9% saline isotonic to red blood cells
34
Effect of osmosis on cells in hypotonic solution
- concentration of water outside the cell is greater than inside the cell - cell gains water - lysis (cells may burst) (blood hemolysis)
35
Effect of osmosis on cells in hypertonic solution
- causes cell to lose water and shrivel (crenate) | - ECF has a higher concentration of non permeating solutes than ICF
36
Ligand Definition and what determines it
Chemical that binds (reversibly) to a receptor site on a protein --charges/shapes must be complementary Determined by conformational shape of the protein
37
Chemical Specificity Definition and what does it determine
ability of a protein-binding site to bind specific ligands determines what can actually bind to the binding site
38
What is the shape of proteins determined by?
determined by amino acid sequence | different amino acid sequences are going to lead to different shapes which will lead to different binding sites
39
True or False | All protein sites only bind to one ligand
False some protein sites only bind to one ligand; others bind to many
40
Affinity Definition and what does it determine
strength of ligand-protein binding determines how likely that the particular bound ligand will leave
41
Chemical specificity depends on the ___; affinity depends on the ____ of the liquid and protein attraction
- shape | - strength
42
What equals a high affinity?
Opposite charges + ligand shape + binding site shape
43
Saturation definition
fraction of total binding sites that are occupied at any given time
44
Why is there competition among different ligands for binding sites?
influenced by the affinity this then impacts the saturation
45
What is carrier-mediated transport?
use a membrane protein to transport substances across membrane
46
What are the three kinds of carriers in carrier- mediated transport?
1. uniport (carries one type of solute) 2. . symport (two or more solutes, moving in the same direction at the same time) 3. antiport (two or more solutes, moving in opposite directions)
47
What is an example of uniport?
calcium pump
48
What is an example of symport?
sodium-glucose transporters
49
What is an example of antiport?
sodium-potassium pump
50
What do the three mechanisms of carrier-mediated transport use?
- facilitated diffusion - primary active transport - secondary active transport
51
Facilitated diffusion is where.....
a carrier moves a solute from hight to low concentration (down the gradient)
52
Primary active transport is where...
a substance moves through a membrane against the gradient
53
Secondary active transport is where...
the carrier moves solute through a membrane (uses ATP indirectly) (uses a combination of facilitated diffusion [symport] with primary active transport [antiport])
54
What does each cycle of the sodium-potassium pump consume?
1 ATP and exchanges 3 sodium for one potassium
55
What is the purpose of the sodium-potassium pump?
-keep potassium concentration higher and sodium concentration lower inside the cell
56
___ ___ influences osmosis which influences ____ ___
solute concentration | cell volume
57
Carrier-mediated transport is a process where....
solute particles move through a membrane by means of a transport protein (uniport, symport, antiport)
58
ATP is not necessary in ___ ___
facilitated diffusion
59
ATP is necessary in ____ ___ ____
Primary active transport
60
What are the three things included in endocytosis?
1. pinocytosis 2. phagocytosis 3. receptor-mediated endocytosis
61
What is pinocytosis?
"cell drinking" - droplets of ECF containing molecules
62
What is Phagocytosis?
"cell eating" - cell surround, engulfs, and digests particle
63
What is receptor-mediated endocytosis?
particles bind to specific receptors on plasma membrane
64
What happens in Exocytosis?
- Discharges material | - Replaces plasma membrane removed by endocytosis
65
What is transcytosis?
transport of material across the cell | capture on one side; release on the other
66
What do receptor- mediated endocytosis and exocytosis do in transcytosis?
receptor-mediated endocytosis moved it into the cell and exocytosis moves it out the other side

Mammalian Physiology 318 (11 decks)

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