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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
Concentration of all osmotically active particles per KG of SOLVENT
Osmolality
26
Determines osmotic pressure between solutions
Osmolality
27
Two solutions have the same osmolarity
Isoosmotic
28
Solution with higher osmolarity
Hyperosmotic
29
Solution with the lower osmolarity
Hypoosmotic
30
Exact amount of pressure required to stop Osmosis
Osmotic Pressure
31
Pressure which needs to be applied by a solution to prevent the inward flow of water across a semi permeable membrane
Osmotic Pressure
32
How do you calculate Osmotic Pressure
Van't Hoff's law
33
Physiologic Implications of OSMOTIC PRESSURE
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
34
Measure of the osmotic pressure of two solutions separated by a semipermeable membrane
Tonicity
35
Factor that can influence the TONICITY of a solution
Solutes that cannot cross the membrane
36
TONICITY and Osmolarity
Osmolarity NOT = TONICITY Osmolarity accounts for ALL solutes Tonicity accounts for only NON-PERMEATING solutes
37
Types of Tonicity
Isotonic - equal Hypertonic - higher Hypotonic - lower than the cytosol
38
Transport of glucose, amino acids, and other polar molecules through the membrane
Carrier-Mediated Transport
39
Example of Carrier-Mediated Transport
Facilitated Diffusion Primary Active Transport Secondary Active Transport
40
Characteristics of Carrier-Mediated Transport
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
Types of ACTIVE TRANSPORT
1˚ Active Transport | 2˚ Active Transport - Co-transport/Countertransport
42
Occurs uphill against an electrochemical gradient Requires direct-input of metabolic energy (active) Carrier-mediated transport that exhibits stereospecificity, saturation and competition
Primary Active Transport
43
Examples of 1˚ Active Transport
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
Transport NA+ from ICF to ECF and K+ from ECF to ICF against electrochemical gradient
Na+/K+ ATPase Energy provided: ATP Stoichiometry - 3Na/2K+
45
Functions of Na+/K+ ATPase
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
Basic requirement in nerve and muscle fibers for transmitting nerve and muscle signals
Electrical potential
47
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
2˚ ACTIVE TRANSPORT | Energy is provided indirectly from the Na+ gradient
48
Inhibition of Na+/K+ ATPase inhibits the secondary active transport. True or False
TRUE. Because Secondary Active Transport utilizes energy from NaK ATPase Transport
49
Types of 2˚ Active Transport
Co-Transport | Counter-transport
50
Differences of Co-transport and Counter transport
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
Multiple, hierarchal steps | Amplification of hormone-receptor binding event
Signaling Pathways
52
Functions involved in Signaling Pathways
Activation of multiple pathways | Regulation of multiple cellular functions
53
How to antagonize/oppose Signaling Pathway
By constitutive and regulated feedback mechanisms
54
``` Identify Signaling Molecules Peptides and Proteins - Catecholamines - Steroid Hormones - Iodothyronines Eicosanoids - Small molecules - ```
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
Types of Cellular Communication
``` Endocrine Signaling Neurocrine Signaling Paracrine Signaling Autocrine Signaling Juxtacrine Signaling ```
56
Transport of hormones along blood stream to a distant organ
Endocrine Signaling
57
Signaling that is also called synaptic transmission | Transport of neurotransmitters from presynaptic cell to a postsynaptic cell
Neurocrine Signaling
58
Release and Diffusion of local hormones with regulatory action on neighboring cells
Paracrine Signaling
59
A cell secretes hormones or chemical messengers that bind to the SAME cell.
Autocrine Signaling
60
Signaling also called as contact-dependent signaling | Transmitted via oligosaccharide, lipid or protein components of a cell membrane
Juxtacrine Signaling
61
In juxtacrine signaling, this is occurred between adjacent cells linked by ________
Gap junctions
62
Examples of each. ``` Endocrine Signaling Neurocrine Signaling Paracrine Signaling Autocrine Signaling Juxtacrine Signaling ```
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
Also called as signal transducers
Receptors
64
Types of Receptors
Membrane receptor | Nuclear receptor
65
Type of Plasma Membrane Receptors
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
Types of Nuclear Receptor
Hormone-receptor complex binds to DNA and regulates the transcription of specific genes
67
Receptor for transcription of genes to alter gene expression
Nuclear Receptor
68
Flow of Nuclear Receptor Signaling
Early primary response >> Gene activation to stimulate other genes >> Biological effect
69
Process by which an extracellular signal activates a membrane receptor Involves SECONDARY MESSENGERS
Signal Transduction
70
Function of Signal Transduction
Signal amplification | Alteration of intracellular molecules creating a response
71
Types of Signal Transduction Pathways
``` G Proteins Ion Channels Protein Kinases - Calmodulin-dependent protein kinases - cAMP dependent protein kinases - aNP-guanylyl cyclases ```
72
Family of Integral transmembrane protein that possess seven transmembrane domains
G Protein-Coupled Signal Transduction Pathways
73
What are the Heterotrimeric complexes of G-protein Coupled Signal Transduction Pathway
∂, ß and y subunits
74
Linked with more than 10,000 different receptor
G Protein-Coupled Signal Transduction Pathway
75
Example of G Protein Coupled Signal Transduction Pathway
Adrenergic Receptors Chemokine Receptors TSH Receptors
76
Active vs Inactive G protein-Coupled Signal Transduction Pathway
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
Signals involved in G protein Coupled Signal Transduction Pathway
Adenylyl Cyclase Phosphodiesterase Phospholipids
78
Method by which kinase is modified in Protein Kinases
Phosphorylation
79
Phosphorylation usually results in a ___________ of the target protein
functional change by: changing enzyme activity modifying cellular location associating with other proteins
80
3 types of Protein Kinases
Calmodulin-dependent Protein Kinases cAMP-dependent Protein Kinases cGMP-dependent Protein Kinases
81
Ion involved in which binding causes conformational alterations in calmodulin on Calmodulin-dependent Protein Kinases
Calcium
82
Phosphorylates specific serine and threonine residues in many proteins (myosin light-chains)
Calmodulin-dependent protein kinase
83
Example for types of Protein Kinases
Calmodulin-dependent -- Muscle cells cAMP dependent -- cGMP dependent -- ANP, NO
84
What facilitates in the conversion of ATP to cAMP in cAMP-dependent Protein Kinases
Adenylyl Cyclase
85
Increased cAMP activates ____________ in cAMP-dependent Protein Kinases
Protein Kinase A
86
In the Kidney, ANP inhibits sodium and water reabsorption by the collecting duct. What type of Protein Kinase is involved?
cGMP-dependent protein kinase *ANP
87
Transport proteins involved in Membrane Transport
Channel Proteins - allow free movement of water and selected ions Carrier Proteins - conformational change to transport molecules

PHYSIOLOGY (13 decks)

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