Lecture 6 - Cell Membranes Flashcards
(19 cards)
What is the main structural component of the cell membrane?
The bilayer of phospholipids.
What does amphipathic mean?
It means one side is hydrophilic (fw water) and the other side is hydrophobic (doesn’t fw water)
Where does fluid exist? How does this affect the structure of the cell membrane?
The fluid exists in both the cell and outside the cell meaning the lipids have to orient themselves in a way that allows the heads to be touching the water while the tails are not.
Why is the phospholipid layer flexible?
Because the lipids are not covalently bonded, they are simply joined by their hatred for water, so they be flip flopping
How does the bilayer of phospholipids form?
Being a sheet of bilayer phospholipids is not favourable, BUT being a little ball around a cell is favourable therefore they do it for fun, AND THEY DO IT SPONTANEOUSLY
What is the difference between saturated and unsaturated hydrogen tails?
Unsaturated hydrocarbon tails won’t freeze if it gets cold but they may leak the cell fluid
Saturated hydrocarbon tails won’t let cell liquid leak if it gets hot but will freeze if cold.
What is the structure, location, and function of cholesterol?
Structure: amphipathic, because one end is polar.
Location: chills with the phospholipid tails
Function: its plugs the gaps to prevent leaking or freezing
What are the two different types of membrane proteins?
- Integral: touch phospholipid layer
- Peripheral: don’t touch phospholipid layer (???)
What is the function of membrane proteins?
Transport molecules
Why do glycolipids and glycoproteins face outwards?
to protect the cell from virus getting in
What are antigens? Which cells have it?
All cells have antigen around membrane. They exist so antibodies can stick on it.
Name the blood types and their respective antigens.
Blood Type: O
Antigen: H
Blood Type: A
Antigen: H & A
Blood Type: B
Antigen: H & B
Blood Type: AB
Antigen: H & A & B
What determines the + or - in blood type?
It is based on the D antigen’s presence.
Rh + means its present and Rh - means its absent.
What are the different antigens as an organic molecule?
Glycolipids attached to the phospholipid bilayer
What do Human RBC Plasma Membranes have?
- Antigen lipids
- Antigen proteins
Why do plant cells not have phospholipids and membrane proteins?
Because they have cell walls so they do not need cholesterol or sugars.
What do Prokaryotic cell plasma membranes?
They have
1. Phospholipids
2. Membrane Proteins
because most prokaryotic cells have a cell wall
- NO SUGARS OR CHOLESTEROL *
Why do cells want more membrane?
for more membrane proteins.
What are ways for cell to increase membrane SA?
IOI
Infolding: for cells with a cell wall
Out folding: for cells with no cell walls
Internal membranes: all eukaryotes have internal membranes.
