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phospholipid bilayer Cheat Sheet (DRAFT) by

This is a draft cheat sheet. It is a work in progress and is not finished yet.

effects on the bilayer

ethanol: causes the cell surface membrane to dissolve
cold temper­ature: saturated fatty acids become more compressed which lessens the fluidity of the bilayer however unsatu­rated fatty acids counteract this by becoming more fluid
warm temper­atures: the membrane becomes more fluid and more permeable, proteins may move around, and the tertiary structure of proteins may denature, the proteins in the cytosk­eleton may also break causing the membrane to collapse
glycop­rotiens are proteins attached to carboh­ydrates and can act as antigens and receptors, or even take part in some reactions
  

transport

osmosis: the net movement of water from an area of higher water potential to an area of lower water potential
active transport: the movement of molecules against their concen­tration gradient with the aid of ATP
bulk transport: the use of endocy­tosis and exocytosis when molecules are too large to enter or leave the cell, this also requires ATP
diffusion: the net movement of molecules down their concen­tration without the use of ATP
facili­tated diffusion: a passive process of the movement of molecules from an area of higher concen­tration to an area of lower concen­tration with the aid of a carrier protein
-diffusion does not require ATP as all molecules have kinetic energy and are always moving no matter if they are stirred or shaken, they move from an area of higher concen­tration to an area of lower concen­tration
-the concen­tration is maintained as the product which enter the cell get used up
factors which affect the rate of diffusion include: temper­ature, diffusion distance, surface area, concen­tration gradient and the size of diffusing molecules
-biolo­gical membranes within cells such as cristae in mitoch­ondria and thykaloids in chloro­plasts are used to increase surface area
  

associated practical

measuring temper­ature
measuring solvents
1) cut pieces of beetroot into samples of the same size using a borer
1) cut pieces of beetroot into samples of the same size using a borer
2) wash each of the samples to remove all the excess pigment released from boring
2) wash each of the samples to remove all the excess pigment released from boring
3) place each of the samples into test tubes containing a specified quantity of water
3) place each of the samples into test tubes containing a specified quantity of water
4) run many water baths at different temper­atures
4) add different volumes of the solvent into the test tubes
5) place the test tubes into the water baths for a specified period of time
5) leave for a specified period of time
6) remove the beetroot to stop more pigment being released
6) remove the beetroot to stop more pigment being released
7) use a colori­meter to measure the light intensity
7) use a colori­meter to measure the light intensity
8) record the results on a table
8) record the results on a table
the phosph­olipid bilayer is partially permeable, and is referred to having a fluid mosaic model, it has the following functions:
1) regulating transport into and out of the cell
2) metabolic pathways
3) antigens and cell signalling receptors
4) release of chemicals from the cell