 | Term | Definition |
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Selectivity related to size and charge of hydrated ion |
Channel |
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Diffusion single file through narrow point |
Channel |
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Selectivity related to molecular interaction of solute substrate |
Carrier |
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Exhibit counter-transport |
Carrier |
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Enzyme like reaction |
Carrier |
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Co-substrates |
Carrier |
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Active Transport |
Is a coupled chemical reaction. ATPases such as Na+/K+ pump. Move solute against gradient. |
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Facillitated Diffusion |
Solutes pass down their gradients. |
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Uniport |
Transport a single solute down its gradient |
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Symport |
Transport of solute against its gradient coupled with the transport of a solute down. Both transported INTO cell. |
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Antiport |
Transport of solute against its gradient coupled with the transport of a solute down. One transported OUT one transported IN |
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Transport is saturable |
True |
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Michaelis Menten Equation |
V = [Vmax]/ 1 + (km/c) |
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V= |
initial rate |
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c= |
concentration of extracellular glucose |
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Vmax= |
rate of transport when all of GLUT1 contain a bound solute |
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Km= |
describes affinity, lower Km the tighter the substrate binds. |
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How many GLUT proteins are there |
12 |
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Where are GLUT2 found |
Liver cells and islet B cells of pancreas |
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Why does GLUT1 have a lower Km than GLUT2 |
When INCREASE of blood glucose from b.v 5mM to about 10mM after a meal, GLUT2 will transport double value of glucose whereas GLUT1 transport level increases slightly |
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What does the GLUT family transport |
Hexoses such as glucose |
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What do islet B cells in the pancreas release |
Insulin after rise in blood glucose. |
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How does Insulin Lower blood glucose |
1)Increase glucose metabolism in muscle 2)Inhibits glucose production in liver |
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Secondary Transport (cotransport) |
Secondary active transport couples movement of one substrate against its concentration gradient to the movement of a second solute down its concentration gradient |
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Competitive Inhibition |
1)Increase Km (lowers affinity) 2) Vmax is unchanged |
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Non Competitive Inhibition |
1)Lowers Vmax 2) Km is unchanged |
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What class of ATP pump is the Na+/K+ pump |
P-class |
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What subunits does the ABC Superfamily of ATPases have |
2 A subunits that the ATP bind to in cytosol. 2 T subunits |
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What is cytosolic pH kept at |
7.2 |
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MCT family transport |
Monocarboxylates |
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gpaAT family transport |
Amino Acids |
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What type of transporter are the GLUT family made of |
Uniporters and Antiporters |
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What type of transporter are the MCT family made of |
Symporters |
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gpaAT family is made of |
Antiporters |
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Describe formation of Lactate |
Glucose ==> 2 lactic acid ==> H+ and lactate- |
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What is the basal plasma concentration of lactate and lactic acid |
1mM (lactic acid 0.0035) and (lactate 0.996) |
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Lactic acid crosses cell membrane by |
By diffusion as it is acidic and more permeable in lipids |
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What % of lactate cross membrane by diffusion |
0.5% |
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