cell membranes general Flashcards
1
Q
- What is the difference between the outer and inner surface of the plasma membrane?
A
- The outer surface of the membrane has chains of sugar, carbs that are part of the glycolipids and glycoproteins
2
Q
- Explain under what circumstances CO2 might diffuse into a palisade cell, how the process takes place?
A
- -Photosynthesis in the palisade cell uses CO2 maintaining a low concentration inside the cell
- The concentration of CO2 outside and in air spaces is higher than inside the cell
- CO2 diffuses into cell down CG,
Cell wall and plasm and membrane are both permeable to CO2
3
Q
- Suggest what might be moved out of a cells in the pancreas by exocytosis?
A
Digestive enzymes, insulin and glucagon
4
Q
- Approximate width of membrane
A
7nm
5
Q
- Function of the intrinsic channel protein
A
Create a water filled channel in which polar ions can pass through
6
Q
- 5 roles of a glycoprotein
A
- Cell adhesion to hold cells together
- attach to water molecules to stabalise membrane
- act as antigens
- cell recognition, precise structure means they can distinguish self from non-self
- transport substances up CG, using ATP (active transport)
- create a water filled channel in which polar substances pass through
7
Q
- How do small substances enter the PM
A
- Simple diffusion, pass through temporary gaps formed by vibrating phospholipids, move down using their own motion of energy
8
Q
- How do Charged, large substances enter the PM
A
- Facilitated diffusion, channel/ carrier protein
- if it’s a gated ion they bind with the protein to open it
- or pass through water filled channel protein down CG
- NO ATP
9
Q
How do substances enter via active transport
A
Transporter proteins required
Requires ATP energy
Atp changes the shape of the transporter proteins, 3 Na ions out, 2 K in