Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

From Flashcardlet > Physiology: Membrane Transport Mechanisms > Flashcards

Physiology: Membrane Transport Mechanisms Flashcards

0
Q

Carrier mediated transport

A

Transport mediated by membrane proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

Transport proteins embedded in the plasma membrane facilitate the movement of ___ and ___ between the ____ and ____

A
  • Ions and solutes

- Cytoplasm and extracellular fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why is the movement of all physiologically important solutes across cell membranes mediated by transport proteins?

A

Because most molecules of biological importance are only sparingly soluble in the lipid core of cell membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Passive transport

A
  • Transport toward equilibrium

- Requires no input of energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Passive transport is carried out by

A
  • Channels

- Transporters (carriers)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Active transport

A
  • Transport away from electrochemical equilibrium

- Requires input of energy that is usually obtained directly or indirectly from the hydrolysis of ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Types of gated ion channels

A
  • Voltage gated

- Ligand gated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Driving forces for passive ion or solute movement are

A
  • Concentration differences

- Voltage differences

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Passive biological transport mechanisms include

A
  • Facilitated diffusion carriers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Primary active transport pathways include

A
  • Plasma membrane and intracellular ion pumps that directly couple ATP hydrolysis to ion movement
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Secondary active transport pathways include

A

sodium-solute cotransport proteins that utilize the potential energy stored in the sodium gradient across the plasma membrane of cells to move Na+ and some other solute across the membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Transporters operate using an _____ mechanism

A

alternate access

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Solute transport by facilitated diffusion are similar to

A
  • Michaelis Menten kinetics of enzyme activity

- Stereospecific recognition reaction between solute and transport protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Example of facilitated diffusion transporters

A

GLUT1- GLUT4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Facilitated diffusion carriers vs ion channels

A
  • Ion channels work faster

- Ion channels do not saturate under physiological conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Intracellular sodium vs extracellular sodium levels in cells

A 
Intracellular = 10mM
Extracellular = 140 mM
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Intracellular vs extracellular potassium levels in cells

A

Intracellular: 140 mM
Extracllular: 3.5-5 mM

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Levels of sodium and potassium in cells represent

A

A balance between the passive leak of ions through the various proteins that facilitate movement across the cell membrane and active transport of these ions by Na,K ATPase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Na,K-ATPase overall process

A
  • Hydrolyzes intracellular ATP
  • For every ATP molecule that is hydrolyzed, the sodium-potassium pump pumps 3 Na+ ions OUT of the cell and 2 K+ INTO the cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What contributes to the negative resting membrane potential in cells?

A

Difference in stoichiometry of NaK transport (3 Na+ out, 2 K+ in)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Why is the sodium potassium pump said to be electrogenic

A

Because it contributes to the negative resting membrane potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

By establishing and maintaining a gradient for sodium across the plasma membrane, the sodium potassium pump ___

A

Essentially stores the energy obtained from ATP hydrolysis in a different from

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Na,K ATPase is inhibited by

A

Cardiac glycosides (digitalis and ouabain)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

V-type ATPases are responsible for

A

Transporting H+ ions into small cytoplasmic vesicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

F-type ATPases are responsible for

A

ATP synthesis in mitochondria

25
Q

Protein kinases

A

Phosphorylate ion channels or transporters

26
Q

Protein phosphatases

A

Dephosphorylation of proteins

27
Q

Insulin-dependent recruitment of GLUT 4 is critical for

A

Returning serum glucose to normal concentrations after feeding

28
Q

What is impaired in type I and type II diabetes

A

trafficking of GLUT 4 transporters

29
Q

Osmosis is

A

the movement of water across a permeable membrane in response to the presence of dissolved solutes

30
Q

Ratio of water molecules to solute molecules (i.e. effective osmotic concentration of plasma)

A

55: 0.29

31
Q

Osmotic strength depends on

A

The number of independent solute species in solution

32
Q

Intracellular volume is affected by

A

The presence of molecules in extracellular fluid

33
Q

Hypotonic solutions contain

A
  • Less than 0.29 mOsM of impermeant solutes
  • Cells swell
  • Water enters the cell down its concentration gradient
34
Q

Hypertonic solutions contain

A
  • Greater than 0.29 mOsM of impermeant solutes

- Cells will shrink

35
Q

Steady state volume of a cell is determined by

A
  • Concentration of impermeant solutes in solution
  • Concentration of solutes such as sodium which are unable to attain concentration equilibrium because of active transport
36
Q

Why does sodium behave as though it does not cross the membrane

A

Because of the sodium pump

37
Q

Role of colloidal electrolytes in regulation of cell volume

A
  • These solutes cannot cross the plasma membrane

- They dilute the intracellular water concentration and induce the influx of water across the plasma membrane by osmosis

38
Q

Ion transport mechanisms that cells activate in the presence of osmotic challenges

A
  • Na, K-ATPase
  • Regulatory volume decrease
  • Regulatory volume increase
39
Q

Regulatory volume decrease

A
  • Activated in hypotonic solutions

- Activation of pathways that allow for the passive efflux of K+ and an anion

40
Q

Regulatory volume increase

A
  • Activated in hypertonic solutions

- Activation of pathways for the passive entry of the Na+ anion

41
Q

Chronic or long term cell volume increase is accomplished by

A

The increased synthesis of intracellular osmolytes such as sorbitol and inositol

42
Q

Epithelia can be classified as either

A
  • Absorptive or secretory
43
Q

Difference between absorptive epithelium and secretory epithelium is due to

A

the presence and location in the cell of different transport proteins

44
Q

Molecules moving across epithelial barriers may take either of two routes:

A
  • Transcellular pathway

- Paracellular pathway

45
Q

Process for absorption via transcellular pathway

A

Molecules pass through apical surface and diffuses through cytoplasm of cell and basses through basal membrane

46
Q

Mucosal surface

A

Apical surface

47
Q

Serosal surface

A

Basal membrane

48
Q

Claudins

A
  • Ion-selective proteins located within tight junctions that determine which ions can move between cells by the paracellular route
49
Q

Na,K-ATPase is concentrated in

A

Basolateral membranes of most epithelia

50
Q

Apical membranes of most epithelia contain

A

Facilitated transport carriers and channels that allow Na+ ions to enter the cell passively

51
Q

Na,K-ATPase in basolateral membrane and transport carriers on apical membrane helps to accomplish

A

the net absorption of Na+

52
Q

Example of absorptive epithelium

A

Renal tubule

53
Q

Mutations in structural genes encoding subunits of the epithelial sodium channel and defects in the trafficking of this protein have been correlated with

A

Liddle’s syndrome (hypertension)

54
Q

Chloride channels are important in the regulation of

A

Intracellular pH

55
Q

Role of sodium/glucose symporter

A
  • Absorption of nutrients

- Plays a role in the treatment of patients with cholera

56
Q

Basic structural unit of exocrine glands

A
  • Simple tubules organized into structurally and functionally distinct regions
  • Acinus
  • Duct
57
Q

Acinus

A
  • Secretory endpiece found in exocrine glands

- Secretes Na+ and Cl-

58
Q

___ drives secretion of water osmotically

A

Secretion of Na+ and Cl-

59
Q

Secretion occurs in response to

A

Binding of a secretagogue to its receptor

From Flashcardlet (110 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions