i need answers to these biology Q's....organic and inorganic.......difusion, osmosis and......?

Question

i need answers to the following plz



1) explain the difference between organic and inorganic substances




2) describe the fluid mosaic model of the cell membrane.




3)what is meant by 'selectivley permayable'?( in cells)




4)distingush between the process of diffusion, osmosis and active transport( i need a diagran...or in this case a link showing diagram)





5) what is facilitated diffusion?




6) what is meant by 'surface area to volume ratio' ?




7) explain why large surface area to volume is important for cells?



plz number ur answers,,,thnx beforehand :)

Answer 1

1) An organic compound is any member of a large class of chemical compounds whose molecules contain carbon and hydrogen; therefore, carbides, carbonates, carbon oxides and elementary carbon are not organic

2) Fluid because the molecules are always changing position with each other and mosaic because it is made of different kinds of molecules.

3) Selectively permeable membranes are membranes which only allow a certain substance or substances through, for example in osmosis, where a cell membrane only allows small (ie. water) molecules through but not solute molecules, as they are too large to pass through the pores.

4)
Active transport: http://www.bbc.co.uk/education/asguru/biology/01cellbiology/05pathways/08active/index.shtml

Diffusion:
http://www.bbc.co.uk/education/asguru/biology/01cellbiology/05pathways/06passivesimple/index.shtml

Osmosis:
http://www.bbc.co.uk/education/asguru/biology/01cellbiology/05pathways/10osmosis/index.shtml

5) Some molecules such as those that are soluble in water, cannot pass through the phospholipids in the bilayer. They are transported across the membrane by carrier proteins. A carrier protein will have a specific binding site for the substance it transports. Solute molecules moving about on either side of the membrane will randomly come into contact with their specific binding site. Once they bind, the protein changes shape and the molecules come off the binding site on the other side of the membrane. (N.B you may want to summarise this :P )

6) This is the ratio of the total surface area of an object (e.g a molecule, a cube of agar jelly, a powder of marble, etc) to it's volume. For example, a marble ball will have only a little surface area for it's volume, whereas the same marble ground into a powder would have a much higher surface area, as there is the surface area of each "grain" and the same volume, so it's "surface area to volume ratio" would be much higher.

7) As cells survive by transporting substances across their boundaries, they would need a large surface area to increase the rate of diffusion, to stop waste products building up within the cell and killing it, and also to provide a fast enough supply of whatever the cell needs.

Hope that helps.

If you're stuck on anything else just look around the bbc AS site:

http://www.bbc.co.uk/education/asguru/biology/intro.shtml

Answer 2

An organic substances is involve with carbons while inorganic substances is not. That's why you can call organic chemistry a carbon chemistry.

Answer 3

1)http://en.wikipedia.org/wiki/Organic_compound
http://en.wikipedia.org/wiki/Inorganic_compound

2)http://en.wikipedia.org/wiki/Cell_membrane

3)http://phschool.com/science/biology_place/biocoach/biomembrane1/permeability.html

4)http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/diffus.html
http://en.wikipedia.org/wiki/Active_transport

5)http://en.wikipedia.org/wiki/Facilitated_diffusion

6)http://en.wikipedia.org/wiki/Surface_area_to_volume_ratio