Biology help PLEASE :-)..... hydrophilic/hydrophobic molecules??

Question

Give two examples of molecules that include both hydrophilic and hydrophobic groups [2 marks]. How do the different parts of these molecules behave differently in water and what implication does this have in a cellular environment? [2 marks] Include a hand drawn diagram in your response. [2 marks]

Answer 1

i know only one  .phospholipids . They have both hydrophilic and hydrophobic groups . They are present in membranes.

Answer 2

i know that oil is hydophbic.. the oil in salad dressing never actually mixes with the water

Answer 3

okay the most obvious molecule would be phospholipids which have a hydrophillic head and hydro phobic tail another example would be soap which also contains both components. when a phospholipid placed in water the hydrophillic portion attaches to the water and any other non-polar objects in the water may attach to the other end of the molecule.

in a cellular environment the presence of a phospholipid bi layer is imminent which allows selective passing of all water and solutes by the cell. the phospholipd bi layer can disallow many molecules into the cell and also allow some essential (larger) molecules through special protein channels

http://micro.magnet.fsu.edu/cells/plasma...

for the diagram jsut draw that picture in a 2D fashion and the outside portions are hydrophillic while the middle portion is hydrophobic.

Answer 4

The first one come across my mind is soap

Soap has a long hydrophobic tail, and a hydophilic head compose of a ionic sodium.

Here is the link with pictures at wikipedia, it is pretty self-explanatory.

http://en.wikipedia.org/wiki/Image:Soapf...

The hydrophilic head loves water, and the hydrophobic tail hates it, so a group of the same molecule forms a bubble, with the head towards the water, and the tails inside the bubble, away from water.