1.3 Membrane structure Flashcards
What does the phospholipid bilayer consist of(Overall)?
A hydrophilic exterior and a hydrophobic interior, with the heads facing outside and the tails facing inside. Also cholesterol and Proteins
What does the phospholipid bilayer consist of(specifically)?
Hydrophilic heads are made of phosphate and glycerol.
Hydrophobic tails are made of two fatty acids, which are either saturated or unsaturated.
What are Chanel proteins and what function do they serve?
Chanel proteins are transmembranal proteins that facilitate the diffusion of ions and other polar molecules (such as water) through the non-polar hydrophobic interior of the phospholipid bilayer.
What are Pump proteins and what function do they serve?
Pump proteins are transmembranal proteins that use ATP to move particles across the membrane in the process of active transport.
Give one example of a pump protein at work.
The membrane of root hair cells have potassium ion pumps.
Key word: when substances enter the cell by diffusion through a protein:
Facilitated diffusion
Other functions of membranal proteins(Aside from facilitated diffusion and active transport)
Receptors for hormones(ie the insulin receptor). Receptors for neurotransmitters at the synapse. Cell Adhesion.
Peripheral proteins on the phospholipid bilayer have what feature that keeps them anchored?
A single hydrocarbon chain that penetrates the phospholipid bilayer
What is the function of Cholesterol in the membrane?
At low temperatures, it prevents the crystalization of the membrane.
At high temperatures, it restricts molecular motion and therefore the fluidity of the membrane.
How does cholesterol carry out its functions?
It disrupts the packing of the phospholipid molecules.
Phospholipids with unsaturated fatty acid tails are what?
They are more fluid than phospholipids with saturated fatty acid tails.
What relationship does water have with the phospholipid layer?
The interaction between the hydrophilic heads and the surrounding water helps stabilize it.
