Membrane Transport I, II, and III Flashcards by anthony Sanchez

protein concentrations in plasma/interstitial/intracellular?

Plasma is 16, interstitial is 10, intracellular is 55

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Nucleus and cytosol in regards to pH?

isotonic, both 7.2

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Where is calcium high besides extracellular?

High in the ER and in the mitochondria

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Is cis or trans side of golgi more acidic?

The trans side, at about 6

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prozac, digitalis, and anti-arrythmic drugs all do what?

target membrane transport

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Equation for Fick’s Law. Include what each variable represents. What if you have lipid solubility or permeability constant?

J = DA(ΔC/Δx)
D= diffusion coefficient
A= surface area for diffusion
delta C= concentration gradient
If you have lipid solubility (beta) it multiplies with the DA, and if you have permeability P it multiplies A instead of D (take d out).

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What is GABA?
What type of channel is the GABA receptor? What happens when GABA binds to the receptor?
What pharmacological agents act on it?

GABA is an inhibitory neurotransmitter in the brain.
GABA receptor is a ligand-gated chloride channel. GABA binds to the receptor, and the channel opens and allows chloride to flow down its electrochemical gradient into the cell.
ethanol, benzodiazepine, volatile anesthetics

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PTPC spans what? What does the opening of it allow?

What are BAX and BAK?

The inner and outer mitochondrial membranes. Opening allows diffusion of solutes resulting in mitochondrial swelling, calcium efflux, and release of cytotoxic proteins.
BAX and BAK are proapoptotic proteins in the OMM that allow release of cytochrome C and other cytotoxic proteins.

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Osmotic pressure equation?

at 37 degrees celsius, 1 mosmole/L is what pressure in mmHg?

pi= iCRT
c=molar concentration of solute
19.33 mmHg

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If something is osmotically active, can it move across a membrane? Would its reflection coefficient be closer to 1 or 0?

No, it cannot. It would have a reflection coefficient closer to 1, not 0.

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equation for EFFECTIVE osmotic pressure?

reflection coefficient x pi (osmotic pressure)

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Lower Km means higher or lower affinity?

Higher affinity

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What does GLUT2 do?

GLUT4? types of transport?

GLUT2 is a facilitated transporter allows glucose to enter the cell, which releases insulin into the blood. Insulin then increases the amount of GLUT4 in muscle and fat cells, which allows them to take up glucose from blood. More GLUT2=glucose in cell, and more insulin in blood, and more GLUT 4.
GLUT4=more glucose in fat and muscle cells.

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complications of diabetes: what two transporters might not work?

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What do cardiotonic steroids do? An example of one? Exogenous v. endogenous?

Bind to and inhibit Na-K pumps. Digoxin, used to treat heart failure. Exogenouos is from plants and amphibians, used to treat heart failure and on poison arrows. Endogenous is implicated in development of hypertension, preclampsia.

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what do H/K ATPases do?

moves hydrogen ions from inside the parietal cells of the stomach (pH ≈ 7.2) against a concentration gradient into the lumen of the stomach. primary active transport

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What is omeprazole?

proton pump inhibitor…. like the H/K ATPase

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What is the pH of the golgi? What do vessicular ATPases do?

golgi is 6. Vesicular ATPases are on organelles of cells, and they acidify the organelles by acting as proton pumps, primary active transport.

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ABC transporters (ATP binding cassette) transporters do what? type?

They are primary active transporters, and specifically they are EXPORTERS. They export xenobiotics (not made in body, such as certain drugs), they export cholesterol from cells, and export bile from cells.

ABC proteins that aren’t transporters?

CFTR is a chloride channel (not a transporter). Channel is open when ATP is bound and subunit is phosphorylated. When open, it allows chloride to leave cell.
SUR- part of K-ATP channel. When glucose is brought into beta cells by GLUT2, the cytoplasm has an increase in ATP. This results in closure of K-ATP channel by SUR. This leads to accumulation of K inside cell and the cell depolarizes. This allows Ca++ to come in, and INSULIN IS RELEASED.

SUR protein is a target for?

That SUR protein is the target for diabetes drugs

Na/glucose transporter is an example of ?

secondary active transport. glucose tags along with Na, which travels into the cell down its concentration gradient.

What does NCX do? NCLX? Type of transport?

NCX is secondary active. puts one calcium out, and brings three sodiums in. NCLX is the same, but also does lithium

Regulatory Volume Increase in Response to a Decrease in Cell Volume involves doing what to what channels?

uptake of both KCl and NaCl…
Activation of Na+/H+ and Cl−/HCO3− exchangers
Activation of Na-K-2Cl cotransporter

Regulatory Volume Decrease in Response to an Increase in Cell Volume involves what channels?

Regulatory volume decrease occurs through loss of KCl Activation of K+ and Cl− channels Activation of the K-Cl cotransporter

playing with the concentration of what ion is most likely to cause problems in the body?

calcium

What is the IP3 receptor? where is it, and what opens it?

ligand-gated ion channel on smooth ER; activation of this receptor opens up a calcium channel that allows calcium to flow down its concentration gradient from the ER into the cytosol; activation of this receptor INCREASES CYTOSOLIC CALCIUM. IP3 binds to the receptor, which opens it.

Ryanodine receptor. | What opens it, where is it? What receptor is it associated with? voltage or ligand gated?

this receptor is also a calcium channel located on the smooth ER; activation of this receptor, like the IP3 receptor, opens up a calcium channel which allows calcium to flow down its concentration gradient from the ER to the cytosol, thereby INCREASING CYTOSOLIC CALCIUM. Increase in cytosolic calcium actually OPENS the ryanodine receptor, allowing more Ca to enter the cytosol. In other cells, depolarization of cell activates dihydopyridine receptor, which opens the ryanodine receptor, letting Ca into the cytosol from ER. RYANODINE RECEPTORS ARE VOLTAGE GATED?

Process for the release of insulin from pancreatic beta cells?

the GLUT2 transporter allows glucose into the pancreatic beta cell. This closes the K+ ATP channel due to increase in ATP, which allows influx of Ca, which then allows the exocytosis of insulin.

role of Ca++ in neurotransmission? | - example of NMDA receptor antagonist?

glutamate binds to NMDA type glutamate receptors on post synaptic cell. this receptor is a ligand-gated Ca++ channel, which then increases intracellular Ca++ levels. Antagonist would be PCP, which can be used as an anesthetic.

3 physiological buffers?

bicarbonate, phosphate, and ammonia buffers.

According to idiots, the GLUT2 transport is what kind of transport? and Na and K transporters?

facilitated diffusion. Na and K transporters are simple diffusion.

the Na/H exchanger does what?

Na+ in, H+ out

the v-type H pump does what?

H+ out, using ATP

Na/H and Na/Ca exchangers contribute to?

ischemia and reperfusion injury. Basically, the Na/Ca exchanger is reversed, and Ca enters the cell. This causes lots of problems like apoptosis, necrosis, hypertrophy, etc. Can end in arrythmias, heart failure, stroke.

are protein levels higher inside cell or outside?

higher inside

is HCO3 higher inside or oustide cell?

outside

How much ATP is spent on membrane transport?

1/3 of all ATP

For this course, ion channels is what kind of diffusion?

simple diffusion

Na/Ca transporter does what? what kind of transport?

secondary active. Moves sodium into the cell down its gradient, and puts Ca out of the cell AGAINST its gradient.

what is PMCA?

moves calcium from cytosol to outside of cell, primary active transport.

What is SERCA?

brings calcium from cytosol into lumen of ER. primary active transport.

Cl/HCO3 exchanger does what?

import Cl, export HC03

K/Cl cotransporter does what/

exports K and Cl

what channel does caffeine open?

brain ryanodine receptors.

5 ways to get amino acids and peptides into epithelium?

1. Na/amino acid cotransporter 2. H/peptide cotransporter 3. amino acid transporter 4. Na/K-ATPase 5. endocytosis