Cell Membranes Flashcards
Intracellular
Inside the cell
Extracellular
Everything outside the cell
Intersitial
Is another term for outside the cell.
-Especially used when many cells are together
What makes up the membrane of a cell?
Phospholipids are the basic structure of a membrane.
Phospholipid Bylayer
Two layers of phospholipids with the lipid tails facing each other.
Why is Cholesterol a necessary component of the Cell Membrane?
- It helps loosen the membrane
- Maintains membrane fluidity and strength
How do proteins help the membrane?
They make the membrane functional.
Transport Proteins
Transports stuff across the cell membrane
- Inside to outside and outside to inside
- very specific, they will only let one thing through
Receptor Proteins
A signaling molecule binds to the receptor outside the cell membrane and on the other side the signal is taken and does something within the cell membrane.
-Very specific
Membrane Bound Enzyme
Help carry out chemical reactions within or without the cell membrane.
Recognition Proteins
It is often a Glycoprotein
- they tag on cells like a finger print saying I am this kind of cell.
- So cells know what kind of cell it is.
Cell Adhesion Molecules
Hold cells together
Tight Junctions
Holding the cell membranes together, so tight that no extracellular fluid can get through.
Desmosomes (Spot or Adhering Junctions)
Proteins hold the cell together with rivets, so extracellular fluid can slip between the membranes.
Gap Junctions
Form a channel between membranes.
- Specialized form of cell communication.
- The extracellular fluid passed through
- -All the cells of the heart are linked this way.
Membrane Transport
Moving things across the membrane.
- Membranes are semi-permeable
- -Membranes will let somethings through easily, some with difficulty, and some not at all.
Factors Effecting Membrane Permeability
Solubility- (fat solubility) if it is fat soluble it can slip across (oxygen)
Size- If it is to big it can’t go through. It needs to be smaller.
–If it is unsaturated phopholipids it can have more pass through them than saturated.
Membrane transport based on passive forces mean
No energy needed to move it across the membrane.
- Diffusion
- Osmosis
- Electrical