Membranes Flashcards
A amino acids polar or non polar? Are they hydrophobic or hydrophilic?
They can be either!
However, non polar amino acids are hydrophobic
Polar amino acids are hydrophilic
Why does freeze fracturing work?
When frozen, the phosphate heads form Hydrogen bonds with the water on outside, while only vanderwaals are holding the inside together. Therefore, the inside splits!
What has higher permeability- non polar or polar molecules?
Non polar molecules have higher permeability than polar molecules!
What 3 things determine diffusion rates?
- Temperature
- Steepness of concentration Gradient
- Size of the molecule
What are two types of facilitated diffusion?
- Channel proteins: ions flow along their electrochemical gradient through a protein channel
- Carrier Proteins: A protein that binds to molecule, changes shape and spits it out the other side!
What is characteristic of active transport?
It moves substances against the concentration gradient- requires energy!
Explain the sodium potassium pump
3 sodium bind to a protein in the membrane. A Phosphate group breaks off of ATP and binds to the protein.
This causes a shape change, spitting out the sodium on the other side.
Potassium now enters the pump, the phosphate group falls off, and the protein reverts back to its shape, spotting the potassium to other side.
What is secondary active transport? How is the sodium potassium pump involved?
Sodium cotransportation- molecules like glucose can get through a membrane when paired with sodium. This is very common in the gut.
For sodium to flow through to bring glucose, it follows the concentration gradient set by the sodium potassium pump
