Plasma Membrane Flashcards
What is the structure of a plasma membrane?
Phospholipid bilayer
What are the key components of plasma membrane?
- Phospholipids
- Proteins
- Cholesterol
- Glycocalyx (carbohydrates)
Describe the structure of a phospholipid.
Polar head- phosphate and glycerol
Non polar tail- two chains of fatty acids
The Fluid Mosaic Model was proposed by ___________________.
Singer and Nicolson
Why is the structure of the plasma membrane described as “Fluid” and “Mosaic”?
Fluid- phospholipids and proteins can move side by side within the layer.
Mosaic- The pattern formed by the random positioning of proteins,
Why is the plasma membrane semi permeable?
It allows the passage of non polar molecules and restricts polar molecules.
What kinds of substances can move through the cell membrane?
Hydrophobic substances.
Small molecules and larger hydrophobic molecules.
eg. CO2, O2 and H20
What kinds of substances cannot move through the cell membrane?
Hydrophilic substances.
Ions, large hydrophilic molecules and proteins.
What are the two types of transportation through the cell membrane?
Active and Passive
______ transportation requires the expenditure ATP.
Active
What is the difference between simple diffusion and osmosis?
Osmosis is the passive transportation of water
True or False: Substance getting transported through simple diffusion have no energy.
False. They have natural kinetic energy.
_________ is the bursting of the cell due to endosmosis.
Cytolysis
___________ is the shrinking of the cell due to exosmosis.
Plasmolysis
What is the difference between flaccidity and plasmolysis?
For plasmolysis to occur, the cell must shrink in a hypertonic environment.
Flaccidity of cell is a result of lack of water in an isotonic environment.
What is the difference between turgidity and cytolysis?
Turgidity is the swelling up of cell, while cytolysis is the bursting of cell in a hypotonic environment.
What are the kinds of passive transport?
Simple diffusion and facilitated diffusion
What is facilitated diffusion?
Transportation of substances across the concentration gradient using transport proteins.
Amino acids and glucose are transported across the plasma membrane through _____________________.
Facilitated diffusion.
Sodium potassium pump operates through ______ transportation.
Active
What are the different kinds of transport proteins?
Channel proteins and carrier proteins
Aquaporins are _______ transport proteins.
Channel
True or False: Channel proteins are integral proteins.
True.
True or False: Carrier proteins change shape or move from one end of the membrane to another to transport substances.
True.
