Cellular Membrane Quiz Flashcards
What is the function of the Plasma Membrane?
To control what enters and leaves the cell
Selective Permeability
Somethings are allowed to pass while others are rejected
What are the molecules of the plasma membrane?
Phospholipids Proteins Carbs Cholesterol CHO
Amphipathic
Hydrophobic and Hydrophilic region
Which part of a phospholipid is polar and hydrophilic?
The head
Which part of a phospholipid is nonpolar/hydrophobic
The tail
Examples of amphipathic molecules
Phospholipids and membrane proteins
Fluid Mosaic Model
Phospholipids and proteins drift laterally within the membrane
How fast do phospholipids move?
100,000,000 times/ second
Compared to phospholipids, how fast to membrane proteins move?
Slower
Describe the relationship between fluidity and temperature.
As temperature increases, fluidity increases
Tell about fluidity and membrane composition
Unsaturated fatty acid tails are kinked and prevented from tight packing
How does cholesterol affect the plasma membrane at warmer temps?
At higher temps, cholesterol restricts phospholipid movement
How does cholesterol affect the plasma membrane at cooler temps?
Acts as a wedge between phospholipids preventing tight packing.
What type of cell is cholesterol found in?
Animal cells ONLY
How to plants adapt to help their plasma membrane as conditions change around them?
Winter Wheat, for example, starts to produce more unsaturated fatty acid tails as winter approaches.
How do cold water fish adapt to their surroundings (concerning their plasma membranes)?
They make more cholesterol and unsaturated fatty acid tails.
Peripheral
Found on surface of outside and inside of membrane
Integral
Embedded within the membrane. So go all the way through the membrane.
Name at LEAST 3 functions of the membrane proteins
Transport Enzymatic activity control Signal transduction Cell to cell recognition Intercellular joining Attachment to the cytoskeleton and extracellular matrix
How many kinds of membrane CHO are their?
2
Glycolipid
CHO connected to a lipid
Glycoprotein
CHO connected to a protein
Give examples of cell to cell recognition
Immunity and WBC
Embryonic development
How do molecules pass thru the Plasma Membrane
Nonpolar pass thru with ease
Polar and large molecules must pass thru transport proteins.
H2O can diffuse thru, but slowly
What are the 2 types of transport proteins
Carrier and channel
Carrier proteins
Carries things and changes shape (specific to molecule)
Channel proteins
ACts as a tunnel for substances (specific to molecule)
Aquaporin
Channel proteins that are specific to water
FLuid
Phospholipids constant motion, proteins drift
Mosaic
Variety of proteins embedded and attached to membrane
What is cholesterols job?
Maintain and restrict membrane flexibility and fluidity
