Ken's 3/4 bio question thread!

[kensan]

Hey guys, decided I would start this thread because I'm guessing I'll need a lot of clarification for this subject.
Thanks so much in advance!!

1. Facilitated diffusion. I've read somewhere that it is through the aid of a protein channel and I've read somewhere else it is when a carrier molecule is involved.  Are they both correct?

2. Hypotonic/hypertonic. Last year I remembered hypotonic by water entering the cell and making it burst (hence the 'O' shape). I was wondering when you use the term hypo/hyper-tonic, are you looking at it from a specific view? Like from the outside of a cell could the solution be hypotonic but from inside the cells point of view hypertonic? I think my teacher was confusing all of us today with this lol

[jasoN-]

1. Carrier molecule (protein) forms a protein channel, this video/animation might help

2. Generally we talk about hypertonic solutions or hypotonic solutions relative to the cell. so hypertonic has higher concentration of something than what's in the cell.
Not sure how the cell's pov can view a hypotonic solution as hypertonic... unless you mean the cell is hypertonic in relation to the solution (which is hypotonic)
When a cell is in a hypertonic solution, water will be drawn out (by osmosis), as the solution has a higher (hyper) concentration of substance than within the cell

[Panicmode]

1. Wikipedia is your friend =D

Facilitated diffusion refers to any form of diffusion that requires a specific protein channel or carrier molecule.

2. Hypertonic/hypotonic/isotonic only refers to the solution in which the cell is in. A cell itself cannot be hypertonic/hypotonic/isotonic, it is placed in a  hypertonic/hypotonic/isotonic solution. The way I think about it is in terms of the movement of water (since in the case of osmosis water basically takes on the role of any other solute performing diffusion). Water moves from an area of high concentration to an area of low concentration. So if inside the cell, the water concentration is higher than the outside, the net movement of water will be to the outside. (from high to low) This will cause the cell to shrivel/grow flaccid. In this case, the solution in which the cell is placed in is called hypertonic. If inside the cell, the water concentration is lower than the outside, the net movement of water will be to the inside of the cell (from high to low). This will cause the cell to swell/grow turgid. In this case, the solution in which the cell is placed in is called hypotonic.

It may be silly, but the way I remember it is

hypotnoic; po rhymes with low; low water concentration inside the cell.

hypertonic; super, super high concentration of water inside the cell.

[Reckoner]

It may be silly, but the way I remember it is

hypotnoic; po rhymes with low; low water concentration inside the cell.

hypertonic; super, super high concentration of water inside the cell.

That's how I remembered it too. Except for the hypertonic solution, my teacher related it to red cordial concentration; the higher the concentration the more hyper you get haha

[kensan]

Awesome! cheers

[kensan]

Ok so I was wondering how in depth we need to know photosynthesis and cellular respiration. All that stuff on kreb's cycle and that is pretty confusing, our teacher just said we need to know the inputs and outputs, is that correct? Thanks

[LOLs99]

There's much more you have to know and I think that chapter is the trickiest part ever...you have to know where it occurs,functions etc etc