Campbell Chapter 7 Flashcards
What is an amphipathic molecule
molecule that has both hydrophilic and hydrophobic regions
Most membrane proteins and membrane Lipids are _______
Amphipathic
How are proteins distributed in the membrane
They form groups of protein that act as long lasting patches
What interactions hold a membrane together
Hydrophobic interactions
Are membranes Stagnant or Fluid
Fluid
What 2 proteins are found in the membrane
integral proteins and peripheral proteins.
What are Integral Proteins
proteins that are permanently embedded in the cell membrane.
What are Peripheral Proteins
proteins that are attached to the surface of a cell or mitochondrial membrane, but are not embedded in it
What are glycolipids
Lipids that have Carbohydrates covalently bonded
What is a selective permeability of the membrane
the membrane allows some substances to cross more easily than others.
What are transport proteins
Transport Proteins are proteins that span the cell membrane, letting in hydrophilic substances without touching the hydrophobic interior of the membrane
What are Aquaporins
Transport Protein that let water molecules into a cell
Polar molecules are hydrophobic or hydrophilic
hydrophilic
nonpolar molecules are hydrophobic or hydrophilic
hydrophobic
What is Diffusion
the movement of particles of any substance so that they spread out into the available space
How is diffusion ruled
In the absence of any other forces, a substance will diffuse from where it is more concentrated to where it is less concentrated.
Does diffusion need energy
no
What is the diffusion of a substance across a biological membrane called
Passive transport
What is Osmosis
The diffusion of free water across a selectively permeable membrane, whether artificial or cellular
What is Tonicity
ability of a surrounding solution to cause a cell to gain or lose
water
If a cell without a cell wall, such as an animal cell, is immersed
in an environment that is isotonic(same tonicity) to the cell what happens
there will be no net movement of water across the plasma membrane
What does being hypertonic mean
a solution has a higher concentration of solute and lower concentration of water
What does being hypotonic mean
a solution has a lower concentration of solute and higher concentration of water
What is Osmoregulation
the control of solute concentrations and
water balance
How does a cell wall change the effect of a hypotonic solution on a cell
the cell wall helps maintain the cell’s water balance.
As water enters the cell, what happens
Cell Swells
What does it mean when a cell is “Turgid”
a cell is swollen and firm due to a high internal water pressure
What does it mean when a cell is “Flaccid”
a cell that has lost its rigidity and is soft and limp due to a loss of water
What is Plasmolysis in plants
contraction of the protoplast of a plant cell as a result of loss of water from the cell.
What is facilitated diffusion
polar molecules and ions blocked by the lipid bilayer of the membrane diffuse passively with the help of transport proteins that span the membrane
What are the types of transport proteins in the cell membrane
channel proteins and carrier proteins.
What are Channel Proteins transport proteins
provide corridors that allow specific molecules or ions to cross
the membrane
What are Carrier transport proteins
proteins that undergo a subtle change in shape that somehow translocates the solute-binding site across the membrane
What type of transport is facilitated diffusion
Passive Transport
What is Active Transport
pump a solute across a membrane against its gradient
requires work; the cell must expend energy
Large molecules, such as proteins and polysaccharides,
generally don’t cross the membrane by diffusion or transport
proteins. Instead what do they do
They leave or enter the membrane packed in vesicles
What is Exocytosis
cell secretes certain molecules by the fusion of vesicles
with the plasma membrane
