Cell Membranes + Structures Flashcards
Describe the Fluid Mosaic Model
Fluid - phospholipids can move freely about the bilayer and can rotate about their axis
Mosaic - scattered pattern of protein molecules
How does a shorter phospholipid tail affect membrane fluidity?
Makes it LESS fluid
How does double bonds in phospholipid tail affect membrane fluidity?
Makes it MORE fluid
Describe the structure of a phospholipid
Made up of 2 fatty acid, hydrocarbon tails, a phosphate group and a glycerol molecule
What part of a phospholipid is hydrophilic and hydrophobic?
Tail = hydrophobic
Head = hydrophilic
Give 3 functions of membranes at SURFACE of a cell
- Separates the cell from its surroundings
- Maintain environment in cell
- Surface antigens identify cell as ‘self’
Give 3 functions of membranes IN a cell
- Compartmentalize environments
- Isolate harmful substances (eg lysosomes)
- Allow vesicles to form for endo/exocytosis
Describe structure of plasma membrane
Phospholipids - heads pointed out, tails in
Cholesterol - between phospholipids
Carbohydrates - on surface
Proteins - in layer (can be halfway or all the way through membrane)
How thick is the plasma membrane?
7nm
What can pass through plasma membrane freely (and what is the exception?) ?
Small, lipid soluable, non-polar, non-charged molecules (water can pass freely through aquaporins because its small)
Name three membrane proteins
- Channel protein
- Transmembrane protein
- Transmembrane glycoprotein
What regions does cholesterol have?
Hydrophobic and hydrophilic
Where is cholesterol found?
Between phospholipids
Whats the role of channel and carrier proteins?
Transport of water soluable, polar, charged molecules (that can’t pass freely through membrane)
Whats the function of cholesterol?
Regulates fluidity
How does temperature affect membrane fluidity?
Higher temperature = MORE fluidity
How does alcohol concentration affect the membrane?
Higher alcohol concentration DISRUPTS membrane
Name 3 cell structures with double membranes
- Nucleus
- Mitochondria
- Chloroplasts
Name the 10 main proteins in eukaryotic cells
- Nucleus 2. Nucleolus 3. Cytoplasm
- Cytoskeleton 5. SER 6. RER 7. Golgi Apparatus 8. Ribosomes
- Mitochondria 10. Plasma membrane
What allows substances in and out of the nucleus?
Nuclear pores