Structure And Function Of Membranes Flashcards
What is the fluid mosaic model?
The theory of the cell membrane formed from a sea of phospholipids embedded with proteins.
What is a glycolipid?
A lipid with a carbohydrate molecule attached.
What is a glycoprotein?
A protein with a carbohydrate molecule attached.
State four functions of membranes at the surface of cells.
- Compartmentalisation; 2. Regulates transport of material into and out of cells; 3. Has surface antigens; 4. Contains receptors for chemical signals.
State 3 functions of membranes within cells.
- Compartmentalisation; 2. Provides a larger surface area for electron carrier proteins; 3. Houses chlorophyll in thylakoid membranes.
The principal design of the plasma membrane consists of two layers; what name is given to these two layers?
Phospholipid bilayer.
Explain the orientation of phospholipids within the bilayer.
Hydrophilic phosphate heads are oriented outwards; hydrophobic fatty acid tails are oriented inwards.
Describe the function of glycoproteins and glycolipids in the phospholipid bilayer.
As markers or antigens; cell signalling; cell communication; cell adhesion.
Give 3 examples of intrinsic proteins.
Channel proteins, carrier proteins, glycoproteins.
Channel proteins and carrier proteins have what main role within the membrane?
Transport.
Describe the position and role of cholesterol in the membrane.
Interspersed between phospholipid molecules; regulates fluidity of membrane.
Describe the structure of a phospholipid.
Glycerol backbone; one hydrophilic phosphate head; two hydrophobic fatty acid tails.
Describe the effects of temperature on membrane structure.
As temperature increases, phospholipids move faster, making the bilayer more fluid and losing its structure.
Describe the effects of ethanol on membrane structure.
Non-polar ethanol molecules disrupt the structure, making the bilayer more fluid and permeable.
Explain why alcohol is used in antiseptic wipes.
Alcohol can disrupt and dissolve bacteria’s membrane, killing them.
