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Physiology > Cell Membrane Transport > Flashcards

Cell Membrane Transport Flashcards

(53 cards)

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1
Q

What is diffusion

A

Process of moving solute molecules away from an area of high concentration towards area of low concentration

Down the concentration gradient

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2
Q

No external energy just kinetic energy of molecules is what type of diffusion

A

Passive

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3
Q

How long does diffusion occur for

A

Until equilibrium is reached

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4
Q

Explain the rate of diffusion

A

Fast over short distances
Slow over long distances
Distance squared relationship

Rate of diffusion is faster at high temp
Rate of diffusion is faster for small molecules
Rate of diffusion is slower across a membrane

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5
Q

Simple diffusion

A

Across no membrane means diffusion is fast

Across a semipermeable membrane allows selected solutes to pass but more slowly
And some solutes can’t pass

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6
Q

What affects the diffusion of Solutes across a cell membrane

A

The type of molecule

Concentration gradient

Temperature

Surface area

Composition of membrane

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7
Q

How does the type of molecule affect its diffusion rate

A

Size (two big)
Polar or non polar

Hydrophobic non polar = pass through

Small uncharged polar molecules = pass

Large uncharted polar molecules = no pass

Charged molecules = no pass

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8
Q

What are hydrophobic non polar molecules

A 
O2
CO2
Lipids
Steroids
Fat soluble molecules
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9
Q

What are small uncharged polar molecules

A

Urea

H2O

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10
Q

Large uncharged polar molecules

A

Glucose
Proteins
Amino acids

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11
Q

What are charged molecules

A

Ions

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12
Q

How does the composition of membrane affect diffusion

A

Simple bilayer vs many proteins and extracellular matrix

Types of phospholipids and sphingolipids

Presence of cholesterol

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13
Q

What is ficks law of diffusion

A

Rate of diffusion

Surface area x concentration gradient x membrane permeability

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14
Q

What is liposomal drug delivery

A

Some drugs may have low bioavailability due to poor solubility

Some drugs may be toxic at useful doses and must be targeted to a specific cell type

Liposomal drug delivery is an emerging technology that may help address these issues

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15
Q

Body fluids are in two compartments ____

A

Extracellular fluid

Intracellular fluid

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16
Q

Intracellular fluid

A

Is 2/3 of the total body water volume. Material moving into and out of the ICF must cross the cell membrane

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17
Q

Extracellular fluid

A

Includes all fluid outside the cells. The ECF is 1/3 of the body fluid volume

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18
Q

The extracellular fluid consists of

A

Interstitial fluid
- which lies between the circulatory system and the cells is 75% of the ECF volume

Plasma
- the liquid matrix of blood is 25% of the ECF volume

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19
Q

Define osmosis

A

The diffusion of water

Water can have a concentration gradient and will diffuse down the gradient

Pure water has the highest concentration of water
Solutes lower the concentration of water

Movement of water can cause pressure

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20
Q

How to compare osmolarities

A

1 glucose = 1 OsM

2 glucose = 2 OsM

1 NaCl = OsM

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21
Q

Higher OsM means ____

Lower OsM means _____

A

hyperosmotic

Hyposomotic

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22
Q

Why is osmolarity important

Study These Flashcards
A

Changing osmolarity of the extracellular solution causes redistribution of water and some solutes in cells

This causes cells to shrink or swell

23
Q

The ability of a solution to shrink or swell cells is its

24
Q

What is the difference between osmolarity and tonicity

Study These Flashcards
A

Osmolarity describes only the number of solute molecules in a cell
Osmolarity can compare any two solutions
Does not tell if a cell swells or shrinks

Tonicity is a comparative term describes whether a cell changes volume
Tonicity compares a solution to a cells intracellular solution
Specifically tells if a cell swells or shrinks

25
Tonicity depends on _____
Concentration of penetrating and non penetrating solutes
26
Penetrating solutes
Small polar and non polar molecules For example urea glycerol ethanol
27
Non penetrating solutes
Ions and larger polar molecules For example Na+ glucose amino acids
28
Hyposmotic solutions are always ____
Hypotonic
29
Intracellular solutes are _____
Non penetrating
30
Water will flow into the compartment that contains the ___ concentration of ____ solutes
Higher Nonpenetrating
31
A _____ is a water filled pore. Can open to both sides
Channel protein
32
What are two examples of channel proteins
Water channels | Ion channels
33
What are two types of channel proteins
Gated | Open
34
____ NEVER form an open channel between the two sides of the membrane
Carrier proteins
35
What are three types of carrier proteins
Uniport (one molecule through) Symport (two molecules through same direction) Antiport (two molecules through different directions)
36
Describe carrier protein process
Passage open to one side Conformational changes occur Transition stage with both gates closed Conformational changes Passage open to other side
37
What are the three categories of energy carrier proteins
Facilitated diffusion Primary active transport Secondary active transport
38
Moving a molecule across the membrane via a carrier protein
Facilitated diffusion
39
True or false | Facilitated diffusion requires ATP
False does not require ATP
40
What's another name for facilitated diffusion
Passive transport
41
True or false | Facilitated diffusion cannot accumulate solute against a concentration gradient
True
42
What is an example of facilitated diffusion
Glucose transporter
43
explain the facilitated diffusion of glucose
High concentration of glucose outside of the cell | Glucose moves through FD Into the cell from high to low
44
Explain primary active transport
Uses ATP Establishes gradients Sometimes called pumps
45
What are the most common molecules to pass through the primary active transport
Na K ATPase (Ca H as well)
46
Describe primary active transport steps
3 Na from the ICF moves into the protein and fits in the walls ATP is used to close the gates turns to ADP Protein changes and 3 Na released into ECF 2 K from the ECF moves into the protein and fits in the walls ATP and protein changes 2 K is released into ICF
47
What is the Na K ATPase pump
Pumps 2 K ions INTO THE CELL Removes 3 Na ions OUT OF THE CELL Hydrolyses ATP This pump accounts for 20 watts of the 100 watts the body produces
48
Secondary active transport
Active transport Does not directly utilize ATP as a source of energy Uses the concentration gradient of one molecule/ions to move another AGAINST its gradient
49
What's an example of a secondary active transporter
Na glucose
50
Explain secondary active transport
Na binds to the carrier from the ECF Na binding creates a site for glucose The glucose binding changes the carrier conformation and opens the protein to the inside Na is released into the cytosol of the cell and glucose follows
51
Epithelial transport utilizes what types of transport
Facilitated diffusion Primary active transport Secondary active transport
52
Transport of material from the lumen of an organ to the ECF is called ____
Absorption
53
Describe the trans-epithelial absorption of glucose
Na glucose symporter brings glucose into the cell AGAINST its gradient using energy stored in the NA concentration gradient (Primary active transport) GLUT transporter transfers glucose to ECF by facilitated diffusion (Secondary active transport) Na K ATPase pumps Na out of the cell keeping ICF Na concentration low (Facilitated diffusion)

Physiology (15 decks)

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