Cell Membranes Flashcards
Describe the structure of a phospholipid
Phosphate Head = hydrophillic
Fatty acid tail = hydrophobic
What is the function of cholesterol in the phosopholipid bilayer
Keeps menbrane stable
What’s the function of Glycolipids and Glycoproteins in the phosopholipid bilayer
For recognition and connecting with other cells
What organelles does the phosopholipid bilayer contain
Glycolipids
Glycoprotiens
Cholesterol
Channel proteins
Entrinsic proteins
Define diffusion
The net movement of molecules orr ions from a region where they are more highly concerntrated to one where their concertration is lower until evenly distributed
What factors effect diffusion and how?
Temp = high temps can denature the membrane and so results in the loss of permeability
pH = extremes can denature membrane proteins and results in slower diffusion rates
What’s facilitated diffusion?
The net movement of molecules or ions with the aid of channel proteins and carrier proteins that spam the membrane
How does protein channels aid diffussion?
- allows specific water soluble ions to pass
- the channels are selective and only open for specific molecules
- ions bind with protein causing it to change
How do carrier proteins effect diffusion?
- allows specific molecules through
- the channels are selective
- molecules such as glucose bind with the protein to change shape
What’s Fick’s law?
diffusion = surface area x difference in conc/length of diffusion pathway
Define active transport
The movement of molecules of ions into or out of a cell from a region of lower concerntration to a region of higher concerntration using ATP and carrier proteins
What is the sodium potassium pump?
where sodium ions are actuvely removed from the cell/organelle while potassium ions are actively taken in from the suuroundings
State the 4 steps to co-transport of glucose
- Na+ transported out o the epithelial cells by Na+/K+ carrier proteins into blood
- maintains a higher conc of Na+ in lumen
- Na+ diffuses into the epithelial cells down conc gradient as Na+ diffuses in, they carry glucose with them
- glucose passes into the blood plasma by faciliated diffusion
What’s the difference between Phagocytosis and Pinocytosis?
Phagocytosis = entry of a solid material
Pinocytosis = entry of a liquid, creates small vesicles
Define osmosis
The passage of water from a region where it has higher water potential to a region where it has a lower water potential through a selective permeable membrane
