Cellular Processes - Lecture 1 Flashcards
Fluid mosaic model describes the membrane as (5)
- Sea of lipids in which proteins float like icebergs
- Membrane is 50% lipid and 50% protein
- Held together by hydrogen bonds
- Lipid is barrier to entry or exit of polar substances
- Proteins are gatekeepers – regulate traffic
True or false. Lipid bilayer is impermeable to non-polar molecules like oxygen and benzene
False
Are fluid structures where lipids can move around within its plane.
Membrane
Fluidity is determined by (2)
- Lipid tail length - the longer the tail, the less fluid the membrane
- Number of double bonds - more double bonds increases fluidity
- Amount of cholesterol - more decreases fluidity
True or false. Lipid bilayer is impermeable to ions like Na+
True
Describe the structure of the lipid bilayer of the cell membrane (2)
- Two back to back layers of 3 types of lipid molecules
2. Cholesterol and glycolipids scattered among a double row of phospholipid molecules
True or false. Lipid bilayer is permeable to lipid soluble molecules like steroids, fatty acids, and some vitamins
True
What does the term amphiphatic mean?
It means that both molecules has both a polar and non-polar region
Are the fundamental units of specialised function in living organisms.
Cells
Size of a cell membrane
8nm
What is a peripheral membrane protein?
Is a type of membrane protein that is attached to either inner or outer of cell membrane and are easily removed from it.
Lipid molecules are impermeable to large uncharged polar molecules like glucose and amino acids
True
True or false. Lipid bilayer is permeable to small uncharged polar molecules like water , urea, glycerol and carbon dioxide
True
It is comprised by lipids (75%). Its bilayer is composed of 2 parallel layers of molecules, where each molecule is amphiphatic
Phospholipids
What is an integral protein?
Integral proteins are membrane proteins that extend into or completely across a cell membrane
