Chapter 7: Cell Membrane 09/19/2024 Flashcards
What is selective permeability?
When the plasma membrane allows some substances to cross more easily than others
What does it mean for a phospholipid to be amphipatic?
It means to contain hydrophobic and hydrophilic regions
What is the fluid mosaic model?
When a membrane has fluid structure with different various proteins
Can phospholipids move?
Only within the plasma membrane in the bilayer. Most of the lipids and proteins drift but cannot flop.
What are peripheral proteins?
Proteins that are bound to the surface of the membrane
What are integral proteins?
Proteins that penetrate the hydrophobic core
What are glycolipids/glycoproteins?
Molecules that help cell-to-cell recognition
What is the behavior of hydrophobic molecules in the membrane?
Hydrophobic and non polar molecules dissolve in the lipid bilayer and pass through the membrane (ex: gases)
What is the behavior of hydrophilic molecules in the membrane?
Hydrophilic molecules and polar molecules do not pass the membrane easily (ex: H2O, macromolecules, anything with charges)
What are transport proteins?
Proteins that allow hydrophilic substances to pass
What are aquaporins/channel proteins?
Proteins that allow and facilitate the passage of water
What is diffusion?
The tendency for a molecule to spread out evenly in a given space. Movement from high to low.
What is osmosis?
The diffusion of water across a selectively permeable membrane. An example of high-to low and is passive transport
What is tonicity?
The ability for a surrounding solution to cause a cell to gain or lose water
What is an isotonic solution?
When the solute concentration is the same as the inside of the cell and there is no water movement in the plasma membrane
What is a hypertonic solution?
When the solute concentration is greater than the inside of the cell and has more on the outside and the cell loses water
What is a hypotonic solution?
When the solute concentrations is less than what is inside the cell. More concentration on the inside and the cell gains water
What is osmoregulation?
When the control of the solute concentration and water balance is necessary for the adaptation for life in such environments
What is a flaccid cell?
When a plant cell and its surroundings are isotonic and no movement in the cell
What is turgid plant cell?
When a plant cell is hypotonic and swells up
What is active transport?
Where there is energy required and flows from low ->high(against the concentration gradient)
What is passive transport?
When there is no energy required and flows from high to ->low(concentration gradient)
What is facilitated diffusion?
The transport of molecules through the use of assisted channels
Are heads hydrophobic or hydrophilic?
Hydrophilic
Is there more movement in saturated or unsaturated fat?
There is more movement in unsaturated fat because it takes up more space. There is little movement in saturated fat because they are packed in a small space.
What can allow more space and fluidity in fats?
At low temperatures, cholesterol can allow more fluidity. At high, it will make it more rigid and less movement
Is the head polar or non-polar?
Polar. The inside is nonpolar
Can hydrocarbons cross through?
Yes. They are nonpolar.
What is the concentration gradient?
The movement of going high to low
What is against the concentration gradient?
The movement of going low to high
What are examples of passive transport?
Diffusion, osmosis, and facilitated difussion
