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4
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1answer
56 views

Do flowers transpire?

I have googled this out but no where found a satisfactory answer. The definition of transpiration states that it is the evaporative loss of water from the aerial surfaces of the plant but I am really ...
0
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0answers
12 views

Are there well studied examples of ERAD-mediated membrane insertion, especially from viruses?

Membrane insertion of transmembrane proteins typically requires highly hydrophobic alpha helixes at the N-terminus, N-terminal signal peptides, tail anchors, or a combination of the three. Byun, H., ...
3
votes
1answer
53 views

Can an emulsion enter a cell?

I've been tempted on cooking.stackexchange to answer a question, and I did, out of my mind. (In retrospect, I shouldn't have done so, based on my lack of citable resources.) I've heard that a water ...
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0answers
12 views

Are receptors integral membrane proteins or peripheral membrane proteins?

In tegral membranes serve as transporters. Peripheral protiens serve as cell adhesion molecules, antigens and enzymes. So what about receptors? Which protiens carry out the duty of receptors?
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0answers
11 views
0
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1answer
74 views

Why is the swelling of bread when placed in water not considered to be caused by osmosis? [closed]

Why is bread swelling up when placed in water not considered to be caused by osmosis? Is there a property of water that should make it leave the bread instead of enter?
2
votes
1answer
836 views

Difference between protein channels, protein carriers and protein pumps?

I'm revising for my biology exam and I don't fully comprehend the difference between protein channels, carriers and pumps. I know that: Protein channels do not require ATP (passive transport) The ...
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0answers
20 views

Mitochodrial osmotic flux

If you incubate mitochondria in isosmotic solution of Tris/EGTA and KCH3COO solution with rotenone, no swelling occurs at first - i.e. no ions enter the matrix so water doesn't follow to compensate ...
2
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0answers
40 views

How do human cells respond to mechanical pressure such as heel contact during walking?

Basically, I'd like to do a full accounting (inventory, assets, liabilities) of a human cell under mechanical pressure. For example, if in steady-state, does the cell consume more or less energy ...
3
votes
1answer
166 views

How do lipid-soluble substances diffuse through the cell membrane?

It’s said that water-soluble substances can diffuse through cell membrane with less ease than lipid-soluble substances because the former encounters impedance in the hydrophobic region of the ...
3
votes
1answer
202 views

Membrane Permeability to Pyruvate

Pyruvate seems to pass easily through the outer membrane of the mitochondrion but has difficulty entering the inner membrane (and gets in by H+ symport). I have two questions: (1) what property of ...
4
votes
1answer
338 views

How can a polar molecule pass through polar channels of proteins in the cell membrane?

To transport a polar molecule through the nonpolar cell membrane, a protein with a polar channel is needed to allow it to diffuse. However, if the molecule is polar and the channel is polar, wouldn't ...
1
vote
2answers
53 views

Question about flux and changes in net flux of molecules across a membrane

I've been reading a book called Principles of Human Physiology by Stanfield 5th edition, and was reading a chapter on membrane transport when I came across a figure question which will be posted below....
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0answers
69 views

How are membrane and extracellular proteins delivered to the target membrane?

In bacteria, either folded or unfolded proteins can be trafficked to the membrane or the extracellular space provided that they have the appropriate signal sequences. Once the chaperones or Signal ...
3
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2answers
4k views

Difference between facilitated diffusion and secondary active transport in cells

Specifically, what is the difference between facilitated diffusion carrier processes (passive transport) and secondary active transport co-transport processes (active transport)? They seem to be the ...
2
votes
1answer
427 views

Active & passive transport question

If an element, ion or molecule is found in a cell is it possible to tell which method of transport was used? for example if a hydrogen or sodium ion was found in the cell could you tell if it got ...
3
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0answers
48 views

can the donnan effect be reversed so phospholipids follow ions? [closed]

I know that there are flipases and flopases that facilitate this sort of thing, but i'm curious about other possible influences. Can donnan effect be reversed so that phospholipids follow ions. For ...
2
votes
1answer
93 views

What is the mechanism responsible for the 'delay' in delayed rectifier potassium channels?

I've been trying to find a comprehensive explanation concerning the nature of the 'delay' in neurons' delayed rectifier potassium channels. As it's written in my intro to neuroscience textbook, these ...
3
votes
1answer
11k views

What is the difference between osmotic potential and osmotic pressure?

Which term is used to calculate water potential? Does osmotic potential mean the same as solute potential?
1
vote
1answer
50 views

Determining and Differentiating specific ATPases

In respects to this certain ATPase transporter. What do i look for in respects to determining what specific kind it is out of: F-ATPases V-ATPases A-ATPases P-ATPases E-ATPases Im assuming that ...
2
votes
1answer
194 views

What is the functional significance of the difference in cardiolipin/cholesterol ratio in different membranes?

I have read somewhere that the plasma membrane has little cardiolipin but excess cholesterol whereas the inner mitochondrial membrane is rich in cardiolipin and has little cholesterol.I just wanted to ...
0
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1answer
44 views

Calculation of water potential

For a mesophyte growing in a moist soil, water potential of its root sap is -3 atm, then how to find the water potential of moist soil and leaf respectively?
4
votes
1answer
558 views

how is the plasma membrane repaired after endocytosis?

When the vesicle is swallowed of course the lipid layer internalizes. My question is how will the top segment of membrane will bind back together when that vesicle took the membrane with it inside ...
5
votes
1answer
202 views

How does a Na+/H+ antiporter drive osmosis in this “osmotic motor”?

This recent paper in Cell describes a cancer cell using osmotic pressure to move in confined spaces. The cell preferentially inserts Na+/H+ antiporters in the leading membrane. I want someone to ...