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PHYSIOLOGY > ME01 - Cellular Transport & Signaling > Flashcards

ME01 - Cellular Transport & Signaling Flashcards

1
Q

Lipid- soluble and Water-soluble on membrane transport

A

Lipid-soluble substances diffuse easily

Water-soluble substances pass through transport proteins

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2
Q 
Complete Table (TRANSPORT)
                                      PASSIVE                    ACTIVE
Conc. gradient        
Carrier-mediated    
Energy Expenditure
Movement              
Motion
A

PASSIVE ACTIVE
Conc. gradient Downhill Uphill
Carrier-mediated Yes or NO YES
(Yes) Fac Diffusion
Energy Expenditure NO YES
Movement Random Uniform
through spaces or With carrier CHON
in comb. of carrier CHON
Motion Normal kinetic motion Requires addtl energy

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3
Q 
Complete Table
                                Gradient   Carrier  Energy  Na Grad  Inhibit Na-K
                                                                                                pump
Simple Diffusion
Fac. Diffusion
Osmosis
1˚ Active Transport
2˚ Active Transport
Co-transport
Counter-transport
A

Gradient Carrier Energy Na Grad Inhibit Na-K
pump
Simple Diffusion Downhill None No No No effect
Fac. Diffusion Downhill Yes No No No effect
Osmosis Uphill No No No No effect
(Use Aquaporins)
1˚ Active Transport Uphill Yes Yes Yes Inhibited
2˚ Active Transport
Co-transport Uphill Yes Yes Yes Inhibited
(same direction)
Counter-transport Uphill Yes Yes Yes Inhibited
(opposite direction)

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4
Q

Types of Passive Transport

A

Diffusion
Facilitated Diffusion
Osmosis

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5
Q

[SIMPLE DIFFUSION]
Occurs ________ from an electrochemical gradient
Via membrane opening or _____________________
_______________ with carrier proteins

A

downhill
intermolecular spaces
No interaction

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6
Q

Factors that determines the rate of diffusion

A

by the amount of substance
velocity of kinetic motion
number and sizes of openings

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7
Q

Governs the rate of diffusion

A

Fick’s Law of Diffusion

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8
Q

Predicts the rate of diffusion of molecules across a biological membrane

A

Fick’s Law of Diffusion

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9
Q

Fick’s Law of Diffusion is
Directly proportional to:
Indirectly proportional to:

A

Directly proportional to: Difference of concentration, Permeability coefficient, Area
Indirectly proportional to: Thickness

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10
Q

Physiologic implications of Fick’s Law of Diffusion

A

Diffusion is FAST at higher concentration gradient
Diffusion is INCREASED at higher permeability
Diffusion is INCREASED at higher areas for diffusion
Diffusion is SLOW when diffusing membrane is thicker

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11
Q

Paths for Simple Diffusion

A
  1. Interstices of the lipid bilayer (through the pores) - High lipid solubility
  2. Through watery channels (AQUAPORINS) - discriminatory in terms of size and charge
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12
Q

Important characteristics of Simple Diffusion through PROTEIN CHANNELS

A
  1. Selectively permeable

2. Voltage or Ligand gated channels - “all-or-none” action

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13
Q

Molecular conformation of the gate or of its chemical bonds respond to the electrical potential across the cell membrane

A

Voltage-gated Channels

Examples: Na-K Channel

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14
Q

“Chemically-gated”
Channels are opened by a chemical substance with the protein
Causes conformational/structural change in the channel

A

Ligand-gated Channel

Example: Acetylcholine Channel

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15
Q

Rate of transport of molecules can never be greater than the rate of conformational change

A

True

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16
Q 
Uniport
Occurs Downhill from an electrochemical gradient
More rapid than simple diffusion
(CARRIER-MEDIATED) Process
NOT GOVERNED by Fick's Law of Diffusion
A

Facilitated Diffusion

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17
Q

Example of Facilitated Diffusion

A

Transport of Glucose in Skeletal muscle via Glut4 transporters

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18
Q

Net movement of water through a semi-permeable membrane caused by a concentration

A

Osmosis

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19
Q

A _______ undergoes OSMOSIS from an area of low solute concentration to an area of high solute concentration

A

SOLVENT (water)

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20
Q

A _________ undergoes DIFFUSION from an area of high solute concentration to an area of low solute concentration

A

SOLUTE

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21
Q

Homogenous mixture composed of 2 or more substances

A

Solution

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22
Q

Parts of a Solution

A

Solute - substance dissolved

Solvent - substance that dissolves the solute

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23
Q

Concentration of all osmotically active particles per L of Solution

A

Osmolarity

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24
Q

Method to measure Osmolarity

A

Freezing point of depression

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25
Q

Concentration of all osmotically active particles per KG of SOLVENT

A

Osmolality

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26
Q

Determines osmotic pressure between solutions

A

Osmolality

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27
Q

Two solutions have the same osmolarity

A

Isoosmotic

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28
Q

Solution with higher osmolarity

A

Hyperosmotic

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29
Q

Solution with the lower osmolarity

A

Hypoosmotic

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30
Q

Exact amount of pressure required to stop Osmosis

A

Osmotic Pressure

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31
Q

Pressure which needs to be applied by a solution to prevent the inward flow of water across a semi permeable membrane

A

Osmotic Pressure

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32
Q

How do you calculate Osmotic Pressure

A

Van’t Hoff’s law

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33
Q

Physiologic Implications of OSMOTIC PRESSURE

A

Osmotic pressure is HIGHER with higher osmolality
Osmotic pressure is HIGHER with high temperature
Higher the osmotic pressure, the GREATER the tendency for water to flow into the solution

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34
Q

Measure of the osmotic pressure of two solutions separated by a semipermeable membrane

A

Tonicity

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35
Q

Factor that can influence the TONICITY of a solution

A

Solutes that cannot cross the membrane

36
Q

TONICITY and Osmolarity

A

Osmolarity NOT = TONICITY
Osmolarity accounts for ALL solutes
Tonicity accounts for only NON-PERMEATING solutes

37
Q

Types of Tonicity

A

Isotonic - equal
Hypertonic - higher
Hypotonic - lower than the cytosol

38
Q

Transport of glucose, amino acids, and other polar molecules through the membrane

A

Carrier-Mediated Transport

39
Q

Example of Carrier-Mediated Transport

A

Facilitated Diffusion
Primary Active Transport
Secondary Active Transport

40
Q

Characteristics of Carrier-Mediated Transport

A

Stereospecificity - specialized to transport specific substance
Saturation - transport rate increases as solute conc increases until all carriers are saturated (T max)
Competition - Structurally related solutes compete for transport sites on carrier molecules Ex. Galactose competes with glucose in the small intestins

41
Q

Types of ACTIVE TRANSPORT

A

1˚ Active Transport

2˚ Active Transport - Co-transport/Countertransport

42
Q

Occurs uphill against an electrochemical gradient
Requires direct-input of metabolic energy (active)
Carrier-mediated transport that exhibits stereospecificity, saturation and competition

A

Primary Active Transport

43
Q

Examples of 1˚ Active Transport

A

Na+/K+ ATPase in all cells
Ca2+ ATPase in sarcoplasmic reticulum
H+/K+ ATPase in parietal cells of stomach
H+-ATPase in intercalated cells of the kidney

44
Q

Transport NA+ from ICF to ECF and K+ from ECF to ICF against electrochemical gradient

A

Na+/K+ ATPase
Energy provided: ATP
Stoichiometry - 3Na/2K+

45
Q

Functions of Na+/K+ ATPase

A

Control of Cell Volume
*Na+/K+ ATPase promotes net loss of ions out of the cell which
initiates osmosis of water rather than into the cells
*Any form of cellular swelling activates Na+/K+ ATPase
*Somehow negates the negative env’t inside the cell

Electrogenic Nature
*Net of 1 POSITIVE CHARGE is moved from the interior to the
exterior of the cell for each cycle of the pump
*Creates an electrical potential across the cell membrane

46
Q

Basic requirement in nerve and muscle fibers for transmitting nerve and muscle signals

A

Electrical potential

47
Q

Transport of two or more solutes is COUPLED

One of the solutes (Na+) is transported “downhill” and provides the energy for the “uphill” transport of other solute

A

2˚ ACTIVE TRANSPORT

Energy is provided indirectly from the Na+ gradient

48
Q

Inhibition of Na+/K+ ATPase inhibits the secondary active transport. True or False

A

TRUE. Because Secondary Active Transport utilizes energy from NaK ATPase Transport

49
Q

Types of 2˚ Active Transport

A

Co-Transport

Counter-transport

50
Q

Differences of Co-transport and Counter transport

A

Co-transpor Counter transport
“symport” “antiport/exchange transport”
occurs if solutes move the same occurs if solutes move in opposite
directions across cell membrane directions across cell membrane
Use ATP does not use ATP
Na+ glucose transport in intestines Na+-Ca2+ in all cells
Na+/K+/2Cl- in loop of Henle Na+/H+ in proximal tubule
Na+/Cl- in distal convoluted tubule

51
Q

Multiple, hierarchal steps

Amplification of hormone-receptor binding event

A

Signaling Pathways

52
Q

Functions involved in Signaling Pathways

A

Activation of multiple pathways

Regulation of multiple cellular functions

53
Q

How to antagonize/oppose Signaling Pathway

A

By constitutive and regulated feedback mechanisms

54
Q 
Identify Signaling Molecules
Peptides and Proteins - 
Catecholamines - 
Steroid Hormones - 
Iodothyronines
Eicosanoids - 
Small molecules -
A

Peptides and Proteins - INSULIN
Catecholamines - EPINEPHRINE, NOREPINEPHRINE
Steroid Hormones - ALDOSTERONE, ESTROGEN
Iodothyronines
Eicosanoids - PROSTAGLANDINS, LEUKOTRIENES, THROMBOXANES, PROSTACYCLINS
Small molecules - Amino acids, Ions, Gases - NO and CO2

55
Q

Types of Cellular Communication

A 
Endocrine Signaling
Neurocrine Signaling
Paracrine Signaling
Autocrine Signaling
Juxtacrine Signaling
56
Q

Transport of hormones along blood stream to a distant organ

A

Endocrine Signaling

57
Q

Signaling that is also called synaptic transmission

Transport of neurotransmitters from presynaptic cell to a postsynaptic cell

A

Neurocrine Signaling

58
Q

Release and Diffusion of local hormones with regulatory action on neighboring cells

A

Paracrine Signaling

59
Q

A cell secretes hormones or chemical messengers that bind to the SAME cell.

A

Autocrine Signaling

60
Q

Signaling also called as contact-dependent signaling

Transmitted via oligosaccharide, lipid or protein components of a cell membrane

A

Juxtacrine Signaling

61
Q

In juxtacrine signaling, this is occurred between adjacent cells linked by ________

A

Gap junctions

62
Q

Examples of each.

Endocrine Signaling
Neurocrine Signaling
Paracrine Signaling
Autocrine Signaling
Juxtacrine Signaling
A

Endocrine Signaling: Hormones (thyroid, insulin, glucagon)
Neurocrine Signaling: Neuromuscular junction
Paracrine Signaling: Testosterone in spermatogenesis, Retinoic in retina
Autocrine Signaling: IL-1 on monocytes
Juxtacrine Signaling: In Gap junction

63
Q

Also called as signal transducers

64
Q

Types of Receptors

A

Membrane receptor

Nuclear receptor

65
Q

Type of Plasma Membrane Receptors

A

Ion-channel linked - transports ions (once stimulated, channel will open for ions only)

G-protein coupled receptor - enzyme linked that produce the signaling

Catalytic receptor - Protein Kinase; Inhibits or activates CHON activity

66
Q

Types of Nuclear Receptor

A

Hormone-receptor complex binds to DNA and regulates the transcription of specific genes

67
Q

Receptor for transcription of genes to alter gene expression

A

Nuclear Receptor

68
Q

Flow of Nuclear Receptor Signaling

A

Early primary response&raquo_space; Gene activation to stimulate other genes&raquo_space; Biological effect

69
Q

Process by which an extracellular signal activates a membrane receptor
Involves SECONDARY MESSENGERS

A

Signal Transduction

70
Q

Function of Signal Transduction

A

Signal amplification

Alteration of intracellular molecules creating a response

71
Q

Types of Signal Transduction Pathways

A 
G Proteins
Ion Channels
Protein Kinases 
      - Calmodulin-dependent protein kinases
      - cAMP dependent protein kinases
      - aNP-guanylyl cyclases
72
Q

Family of Integral transmembrane protein that possess seven transmembrane domains

A

G Protein-Coupled Signal Transduction Pathways

73
Q

What are the Heterotrimeric complexes of G-protein Coupled Signal Transduction Pathway

A

∂, ß and y subunits

74
Q

Linked with more than 10,000 different receptor

A

G Protein-Coupled Signal Transduction Pathway

75
Q

Example of G Protein Coupled Signal Transduction Pathway

A

Adrenergic Receptors
Chemokine Receptors
TSH Receptors

76
Q

Active vs Inactive G protein-Coupled Signal Transduction Pathway

A

ACTIVE INACTIVE
GTP w alpha subunit GDP
Activation via guanine nucleotide Inactivation via GTPase-acc.
exchange factors (GEFs) proteins(GAPS) and RGS proteins
Regulation of G protein signaling
Desentization and endocytic
removal (B-arrestins)

77
Q

Signals involved in G protein Coupled Signal Transduction Pathway

A

Adenylyl Cyclase
Phosphodiesterase
Phospholipids

78
Q

Method by which kinase is modified in Protein Kinases

A

Phosphorylation

79
Q

Phosphorylation usually results in a ___________ of the target protein

A

functional change by:
changing enzyme activity
modifying cellular location
associating with other proteins

80
Q

3 types of Protein Kinases

A

Calmodulin-dependent Protein Kinases
cAMP-dependent Protein Kinases
cGMP-dependent Protein Kinases

81
Q

Ion involved in which binding causes conformational alterations in calmodulin on Calmodulin-dependent Protein Kinases

82
Q

Phosphorylates specific serine and threonine residues in many proteins (myosin light-chains)

A

Calmodulin-dependent protein kinase

83
Q

Example for types of Protein Kinases

A

Calmodulin-dependent – Muscle cells
cAMP dependent –
cGMP dependent – ANP, NO

84
Q

What facilitates in the conversion of ATP to cAMP in cAMP-dependent Protein Kinases

A

Adenylyl Cyclase

85
Q

Increased cAMP activates ____________ in cAMP-dependent Protein Kinases

A

Protein Kinase A

86
Q

In the Kidney, ANP inhibits sodium and water reabsorption by the collecting duct. What type of Protein Kinase is involved?

A

cGMP-dependent protein kinase *ANP

87
Q

Transport proteins involved in Membrane Transport

A

Channel Proteins - allow free movement of water and selected ions
Carrier Proteins - conformational change to transport molecules

PHYSIOLOGY (13 decks)

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