Biology B4 (complete)

Question 1

The fluid mosaic model

Answer 1

used to discribe the plasma membrane due to the mixture of diffrent compounds that form it and their movements

Question 2

Phospholipids bilayer

Answer 2

• made up of two layers of phospholipids

Question 3

phospolipid heads

Answer 3

• hydrophilic due to negative charge so they face the outside
• made of a phospahte group with a negative charge and a glycerol molecule

Question 4

phospholipid tail

Answer 4

• made of two fatty acid chains
• no charge causes them to be hydrophobic
• attracts other lipids

Question 5

cholestrol in the plasma membrane

Answer 5

• embeded in the membrane
• retricts latarol movement
• makes the membrane less fluid at high tempretures
• prevents water and ions leaking out of the cell in turn preventing the cell bursting

Question 6

proteins in the plama membrane

Answer 6

• enbeded across the cell surface membrane

Question 7

peripheral proteins

Answer 7

• provide suport
• connect proteins to lipids
• act as receptors connecting to other molecules

Question 8

integral proteins

Answer 8

can act as either a channel or carrier protein, transporting molecules into and out of the cell

Question 9

protein channels

Answer 9

fill with water to enable water soluble ions to disolve and diffuse through the channel

Question 10

carrier proteins

Answer 10

• requires the hydrolosis of ATP to ADP and pi causing a change of shape so it can tranport them to the other side.
• involves the binding of large molecule to the protein

Question 11

Active transport

Answer 11

movement of molecules against a concentration gradient from a region of low concentration to a region of high concentrations

Question 12

co-transport

Answer 12

the coupled movement of one molecule down it concentration gradient with a second moving against its concentration gradiant.