Biology Unit 3 Questions Megathread

[Russ]

Well there's a naming system in chemistry that goes alpha/beta/etc. but it's got no relevance to the role of the atom

[iNerd]

Well there's a naming system in chemistry that goes alpha/beta/etc. but it's got no relevance to the role of the atom

Sort of relevant - but why do most elements end in IUM?

[Drunk]

Might sound like a stupid question, but why do ions have trouble getting through membranes? I probably would have heard the answer somewhere already, but it's completely slipped my mind at the moment.

Does it have to do with polarity or anything like that?

[shinny]

Might sound like a stupid question, but why do ions have trouble getting through membranes? I probably would have heard the answer somewhere already, but it's completely slipped my mind at the moment.

Does it have to do with polarity or anything like that?

Yeh, kinda. Basically ions are charged (not polar - read my last post for the difference between them), so they can't get through the non-polar phospholipid bi-layer.

[Russ]

Well there's a naming system in chemistry that goes alpha/beta/etc. but it's got no relevance to the role of the atom

Sort of relevant - but why do most elements end in IUM?

At a guess it's a latin suffix that means something relevant

[Drunk]

Yeh, kinda. Basically ions are charged (not polar - read my last post for the difference between them), so they can't get through the non-polar phospholipid bi-layer.

Right, but I was reading on Douchy's forum, and he said that the fatty acid tails of the phospholipids repel ions! Aren't the fatty acid tails supposed to be non-polar? If so, shouldn't it be that the phosphate heads are the ones that repel ions?

[dooodyo]

Oh haha,

Actually no, infact the non-polar fatty acid tails don't
interact with the ions, they move away from anything
charged like water and ions. Where as the phosphate
heads would be attracted to the charged ions and so
the ions would never be able to pass through the
membrane. 

[pi]

Well there's a naming system in chemistry that goes alpha/beta/etc. but it's got no relevance to the role of the atom

Sort of relevant - but why do most elements end in IUM?

Its just tradition, but is is now part of the official naming system for new elements I think

[Russ]

Well the latin root is apparently

Suffix used to form nouns, sometimes having the sense of bigger or more complicated.

which makes sense

[WhoTookMyUsername]

What is the difference between osmotic gradient and osmotic pressure? (can osmotic pressure simply refer to a change in osmotic gradient as there is more 'pressure' on 1 side of membrane after osmosis occurs?

[pi]

The osmotic gradient is the difference in concentration between two solutions on either side of a semipermeable membrane.

The osmotic pressure is the pressure which needs to be applied to a solution to prevent the inward flow of water across a semipermeable membrane (helps with turgidity).

[WhoTookMyUsername]

Given Substance A containing more solute than B, with a net movment of water into A initially, but gradually decreasing, can this pressure be referred to as osmotic pressure?

[pi]

Given Substance A containing more solute than B, with a net movment of water into A initially, but gradually decreasing, can this pressure be referred to as osmotic pressure?

I think so

[WhoTookMyUsername]

is it osmotic pressure or simply equilibrium of osmotic gradient or both? :DS

[dooodyo]

I would say its simply equilibrium of osmotic gradient, Oh but it would depend on the
type of cell right?

I thought that if it was a plant cell then it would appropriate to use the term
osmotic pressure