Biology Unit 3 Questions Megathread

[shinny]

Osmotic pressure refers to the pressure on just one side of the semi-permeable membrane caused by water wanting to diffuse to the other side. However, unless there's nothing on the other side of the membrane, there's going to be a osmotic pressure on the other side as well which opposes that pressure and effectively cancels each other out to some extent. The remaining force is the osmotic gradient and can be seen to be the net force resulting.

For example, there might be 100 osmoles on one side, 90 on the other, and a osmotic gradient of 10 osm.

[WhoTookMyUsername]

Thanks that clears it up

So for example

If A and B are seperated by a semipermeable membrtane and both the membrane and substance enclosing the solutions is *invincible*, and solution A has an Infinitely higher solute concentration, then eventually as solution A filled, the net movement of water would stop *before* the gradient has reached equiligrium as the imprenatrable substance counters it with an osmotic gradient :?

[shinny]

Thanks that clears it up

So for example

If A and B are seperated by a semipermeable membrtane and both the membrane and substance enclosing the solutions is *invincible*, and solution A has an Infinitely higher solute concentration, then eventually as solution A filled, the net movement of water would stop *before* the gradient has reached equiligrium as the imprenatrable substance counters it with an osmotic gradient :?

...whut? How can this invincible substance have an osmotic gradient itself? Only a solution can have an osmotic gradient. Maybe try explaining again what you mean with just a glass container, a semi-permeable membrane and tangible amounts of solution?

[WhoTookMyUsername]

lol. I meant solutions in invicible container

yeah i guuess it was probably not necessary

ok..


So


Solution A and Solution B are seperated in a glass contaner (with a lid) by a semipermeable membrane.

Solution A contains a much higher solute conc. than B
Water from solution B flows into solution A until Solution A has filled up and is stopped from filling more by the lid, but it still has a higher solute conc.

Is this an example of 'osmotic gradient'?

[shinny]

lol. I meant solutions in invicible container

yeah i guuess it was probably not necessary

ok..


So


Solution A and Solution B are seperated in a glass contaner (with a lid) by a semipermeable membrane.

Solution A contains a much higher solute conc. than B
Water from solution B flows into solution A until Solution A has filled up and is stopped from filling more by the lid, but it still has a higher solute conc.

Is this an example of 'osmotic gradient'?

Yeh, I guess. I don't see why you need such an elaborate set-up though. An osmotic gradient doesn't need to be permanently there to count as one. It can just be a temporary thing until an equilibrium is established.

[WhoTookMyUsername]

m... does sheer 'mass of increasing water' count as osmotic pressure?

[shinny]

m... does sheer 'mass of increasing water' count as osmotic pressure?

That would be hydrostatic pressure increasing due to an increased mass. Hydrostatic pressure in a basic sense refers to the weight of the water as affected by gravity creating pressure against the walls of its container. Osmotic pressure only refers to pressure resulting from differences in osmolarity. So by diluting the water, you'd probably create an osmotic pressure anyway. However, the 'mass' itself as you were asking doesn't (well, indirectly does). Hopefully you understand the distinction I'm trying to show here =/

Even if you don't, hydrostatic pressure isn't a concept covered in Biology 3/4 though, so don't worry about it. It is equally important as osmotic pressure when it comes to haemodynamics and such in the human body though.

[WhoTookMyUsername]

thanks i think i understand now

Does Globular and fibrous refer to tertiary or quaternary structure?

[pi]

Pretty sure it can be used for either, but usually tertiary as most proteins don't have a quaternary structure.

[WhoTookMyUsername]

lol. NOB got it wrong then, NOB said, globular and fibrous are quartnery structures, therfore suggesting all enzymes have a quaternary structure

[pi]

The spherical structure is induced by the protein's tertiary structure.

From here. Seems NoB may be wrong here

[LachieEvans]

Definitely tertiary though many fibrous 'proteins' band together to form a bigger fibrous 'protein' with other molecules holding it together thus giving it a quarternary structure..

[WhoTookMyUsername]

What exact term woudl you describe the capabilities of monsaccharides ?

-An immediate source of chemical energy

or

- The immediate precursor to useable ATP

-The most immediate chemical energy source?

[The Detective]

I think an immediate source of chemical energy would be okay

[lexitu]

Almost definitely 'The immediate precursor to useable ATP'.