8.1 Fluid Mosaic Model Flashcards
1
Q
What does plasma membrane do?
A
Plays roles in signaling, entry of nutrients and expulsion of waste, cell recognition, transport of materials between tissues, and even electronic functions.
2
Q
Stabilizing molecules of cell membranes?
A
- cholesterol and protein
3
Q
Stretchy, flexible component of cell membrane?
A
- Phospholipids
4
Q
Cell (plasma) membrane
A
- a semipermeable phospholipid bilayer
- selectivity is mediated by various channels and carriers that poke holes in the membrane and membrane itself
- Composed primarily of two layers of phospholipids, the cell membrane permits fat-soluble compounds to cross easily, while larger and water-soluble compounds must seek alternative entry
- also contain proteins embedded within the lipid bilayer that act as cellular receptors during signal transduction. These proteins play an important role in regulating and maintaining overall cellular activity.
5
Q
What does phospholipid bilayer include?
A
- proteins and distinct signaling areas within lipid rafts
- Carbohydrates associated with membrane-bound proteins create a glycoprotein coat.
- Plants, bacteria and fungi walls have more carbs.
6
Q
How do phospholipids move rapidly in the plane of the membrane?
A
- Simple diffusion
7
Q
Lipid Rafts
A
- Collections of similar lipids with or without associated proteins that serve as attachment points for other biomolecules; these rafts often serve roles in signaling.
8
Q
Can lipids move between membrane layers?
A
- Yes, but this is
energetically unfavorable because the polar head group of the phospholipid must be forced through the nonpolar tail region in the interior of the membrane. - flippases assist in the transition or “flip” between layers
9
Q
A