Membrane Structure and Function Flashcards
What kind of molecules go through the phospholipid bilayer quickly?
Hydrophobic/nonpolar molecules
What kind of molecules go through the phospholipid bilayer slowly?
Small, uncharged polar molecules
What kind of molecules do not go through the phospholipid bilayer at all?
Large, uncharged polar molecules and ions
How can a cell exchange polar/larger molecules with its environment?
By placing channels, pores, and carriers in the lipid bilayer
Can trans-membrane (integral including) proteins diffuse laterally in the membrane?
If they are not connected to the cytoskeleton or the extracellular matrix (ECM) or connected to proteins of another cell
How do we move large molecules into and out of the cell?
Endocytosis and exocytosis
List the functions of membrane proteins
- Transport
- Enzymatic Activity
- Signal Transduction
- Intercellular Joining
- Cell-Cell Recognition
- Attachment to the cytoskeleton and extracellular matrix (ECM)
What is the function of the cell coat?
Protects cells against mechanical and chemical damage; aids in cell recognition
What is the cytoplasm made of?
Cytosol
In what conditions is the membrane fluid at low temperatures?
- Many phospholipids
- Unsaturated hydrocarbon tails
How is cholesterol a fluidity buffer?
- Restrains phospholipid movement at high temperatures, making it less fluid
- Hinders close packing of phospholipids at low temperatures
Passive Transport
No energy needed
- Simple
- Facilitated
- Osmosis
What does glucose require?
Carrier protein (facilitated diffusion)`
Active Transport
Energy needed; against concentration gradient
