The Fluid Mosaic Model of Membranes & Specific Functions of Membrane Proteins Flashcards
1
Q
What does this model imply?
A
- Membranes are fluid
- Substances are able to move within and through membranes in a fluid manner
2
Q
What do cell membranes consist of?
A
- Phospholipid bilayer
- Proteins
- Cholesterol
- Glycolipids and glycoproteins
3
Q
Phospholipid bilayer
A
- A double layer of phospholipids made up of hydrophobic tails and hydrophilic heads
4
Q
Two types of proteins
A
- Peripheral Proteins
- Integral Proteins
5
Q
Peripheral Proteins
A
- Found on either the external or internal surface of the membrane
- They are hydrophilic
6
Q
Integral Proteins
A
- Also called transmembrane proteins
- Span from the extracellular side to the intracellular side of the membrane
- Mostly hydrophobic
7
Q
Integral Channel Protein
A
- They have a transport channel or tunnel in their centres
8
Q
Cholestral
A
- Steroid-based lipid
- Gives the membrane flexibility
- At low temps, keeps fluidity and prevents hardening
- At high temps, maintains rigidity of membrane
9
Q
Glycoproteins
A
Carbohydrate chains attached to proteins
10
Q
Glycolipids
A
Carbohydrate chains attached to lipids
11
Q
What do glycoproteins and glycolipids have in common?
A
- Only found extracellulary
- Act as surface-markers or fingerprints so that diff cells can be distinguished between
- Not in plant cells
12
Q
Specific Functions of Membrane-Proteins
A
- Transport
- Enzymatic Activity
- Signal Transduction
- Cell-to-cell recognition
- Intercellular joining
- Attachment to the cytoskeleton and extracellular matrix
13
Q
Transport
A
- Proteins act like hydrophilic channels
- Also act like a shuttling mechanism to pump substances across membranes
14
Q
Enzymatic Activity
A
- Enzymes embedded in the membrane can have open active sites to catalyze processes
- Enzymes can work together to produce important products for metabolic pathways
15
Q
Signal Transduction
A
A membrane receptor protein can have binding sites for signalling molecules that allow the protein to relay the message along to the interior of the cell
