Cell membranes, permeability, transport, and more! Flashcards
What is the gateway for the cell?
the cell membrane
What is the makeup of the cell membrane?
- **Phosopholipid bilayer (allows cell to be in a watery environment);
- **Proteins (carriers, channels, receptors & anchors);
- Cholesterol (prevents fatty acids from sticking);
- Carbohydrates ( receptors, identification)
Why is homeostasis important?
For a cell to maintain a balance, it must control
what’s in and what’s out
selective permeability
property of the cell membrane:
only certain substances are allowed to
pass through the membrane.
What is diffusion?
movement of particles from a high concentration
to a low concentration.
Why is diffusion important?
Diffusion helps reach equilibrium - or equal concentrations throughout the cell
What is osmosis?
diffusion of water, water, water across
a selectively permeable membrane
What happens to a cell in a hypotonic solution?
water moves into the cell
What happens to a cell in an isotonic solution?
equal water & solutes; water moves in and out
What happens to a cell in a hypertonic solution?
water moves out of the cell >> low water / high solute concentration
What is facilitated diffusion?
carrier proteins help the movement of particles across the membrane
What makes active or passive transport different?
-
energy!!
- acitive transport requires energy
-
concentration gradients
- passive moves high → low
- active moves low → high
What is endocytosis?
(ENter)
the process of taking in large items through wrapping the membrane around them
(to make pouches - vessicles)
What is exocytosis?
EXit
the process of expelling large wastes through fusing vessicles with the membrane
