Structure and Function of Plasma Membranes Flashcards
1
Q
Why is the fluid mosaic model named as so?
A
Fluid - Components can move freely along the membrane
Mosaic - Components of different shapes and sizes all fit together
2
Q
What is the plasma membrane made up of?
A
A phospholipid bilayer
3
Q
What is a phospholipid made up of?
A
1 Phosphate head
1 Glycerol backbone
2 Fatty acid tails
4
Q
Is a phospholipid head or tail hydrophilic?
A
Head
5
Q
What are some functions of the phospholipid bilayer?
A
- Compartmentalisation
- Site of chemical reactions
- Acts as a barrier
6
Q
Where and what chemical reactions take place (example)?
A
- Enzymes/proteins crucial for respiration and photosynthesis in mitochondria and chloroplast plasma membrane
7
Q
How is the membrane a barrier?
A
- Partially permaeble
- Only allows small, lipid-soluble, non polar substances to diffuse across
8
Q
What is a carrier protein?
A
- Instrinic protein
- Used to transport molecules across a membrane
9
Q
How does a carrier protein work?
A
- Can change shape using energy to face outwards
- Mainly active transport
- Can be facilitated diffusion if eg polar
- Can be selective
10
Q
How does a channel protein work?
A
- Facilitated diffusion
- Can be selective
11
Q
What are glycolipids and glycoproteins and what do they do?
A
- Branches
- Act as an antigen
- Act as a receptor for cell signalling
12
Q
What is the function of cholesterol?
A
- Regulates fluidity
