Plasma Membrane + Transport Systems Flashcards
What is the main function of the plasma membrane?
Tao separate the inside ang outsize of the cell.
What is the special characteristic that plasma membranes have?
Semi-Permeable; phospholipid bilayer
What is the most abundant lipid at the plasma membrane?
Phospholipid
What is the Fluid Mosaic Model?
Phospholipid (fluid) + Protein, Carbohydrates, Cholesterol (mosaic)
Phospholipids are AMPHIPATHIC. What does that mean?
It has both hydrophobic ang hydrophilic properties.
What is the difference between surface and peripheral protein?
Surface (permanent); Peripheral (temporary)
What are the factors that affect membrane fluidity?
Temperature and Cholesterol
What happens to the membrane when the temperature is higher?
Unsaturated hydrocarbon tails become more permeable
What happens to the membrane when the temperature is lower?
It becomes more solid. Saturated hydrocarbon tails become more packed together
What is the role of cholesterol in the plasma membrane?
Homeostasis and adaptability. Cholesterol reduces fluidity at higher temperatures and hinders solidification in lower temperatures.
How could some organisms adapt in extreme conditions?
Evolution of differences in membrane lipid composition.
What are the 2 main kinds of protein at the plasma membrane?
Integral and peripheral
What is the main function of peripheral proteins?
- Transport
- Enzymatic activity
- Signal transduction
- Cell to cell recognition
- Intercellular joining
- Ecm
What is the roles of carbohydrates in plasma membranes?
Cell to cell recognition. It can bond to lipids or more commonly proteins. Important in tackling diseases.
What are the 2 main kinds of transport mechanisms?
Active and Passive
What does active transport mean?
Needs atp; goes against concentration gradient
What does passive transport mean?
Doesn’t need atp
What is diffusion?
High to low concentration
What is facilitated diffusion?
Assisted by TRANSPORT PROTEIN to speed up process.
What is osmosis?
Diffusion of water. Water moves at the higher concentration of solute.
What is tonicity?
Ability of solution to gain/lose water
What is isotonic?
Equal water in and out (flaccid)
What is hypotonic?
More water inside (turgid)
What is hypertonic?
Less water inside. (Plasmolyzed)
Describe exocytosis and endocytosis.
Exocytosis - out the cell; endocytosis - in to the cell
According to the fluid mosaic model of cell membranes, phospholipids ________.
can move laterally along the plane of the membrane
Which of the following types of molecules are hydrophilic and therefore excluded from the hydrophobic portion of the phospholipid bilayer?
peripheral membrane proteins
According to the fluid mosaic model, a membrane ________
is composed of a fluid bilayer of phospholipids with embedded amphipathic proteins
For a protein to be an integral membrane protein, it would have to be ________.
exposed on only one surface of the membrane
A phospholipid bilayer with equal amounts of saturated and unsaturated fatty acids displays a specific permeability to glucose. What effect will increasing the proportion of unsaturated fatty acids in the bilayer have on the membrane’s permeability to glucose?
Permeability to glucose will increase.
