Molecular PPT 2 Flashcards
(43 cards)
What is the difference between extracellular space and intracellular space?
Extracellular space contains more sodium and chloride
Intracellular space contains more Potassium, and proteins
What are membrane proteins good for?
Transport
Membrane proteins can act as….
Channels and carriers
What is the difference between a channel and a carrier?
Channels are spaces all the way through the protein molecule that allows transport to the other side
Carriers/Transport proteins bind with molecules or ions and conformational changes in the protein move the substances to the other side of the membrane
By what processes can substances be transported through the cell membrane?
Passive transport or Diffusion
And Active Transport
What is the difference between passive transport (Diffusion) and active transport?
Passive transport moves down the concentration gradient and does not require energy. While active transport moves against the concentration gradient and requires energy
What are the two types of passive transport?
1) Simple diffusion
2) Facilitated Diffusion
What makes facilitated Diffusion different from simple Diffusion?
Facilitated Diffusion goes through carriers or transporter
What is osmosis and what type of Diffusion is it?
Diffusion of water and simple diffusion
What type of passive transport is this:
Molecule moves through the lipid bilayer or through protein channels which are selective protein channels or gated channels?
Simple diffusion
In terms of diffusion through protein channels, which are highly selective. Where does their selectivity come from?
Characteristics like:
Diameter
Shape
Nature of the electrical charges and bonds along its inside surface
In terms of Diffusion through gated channels: what does the gate of the channel control?
The gate of the channel controls ion permeability
What are several types of stimuli that can open ion channels?
1) changes in voltage across the membrane
2) ligand (intra or extracellular)
3) mechanical stress
In terms of Voltage gated channels which is a form of passive transport: where are they present?
Present in the plasma membrane of all excitable cells
What are some examples where voltage gated channels can be found?
Nerve, muscle, endocrine, and egg cells
What are voltage gated channels responsible for?
Responsible for neurons ability to transmit information along their length and to release neurotransmitter
In terms of voltage gated channels: what is the name of the range of membrane potentials that cause them to open?
Channels threshold
What is a channels Threshold?
Minimum membrane potential that causes opening of the channel
Where are ligand gated channels found?
Skeletal muscle cells and some neurons of the autonomic nervous system and brain
How does a ligand gated channel open?
In response to ligand binding
In terms of facilitated Diffusion or carrier mediated diffusion: what facilitates diffusion across the membrane?
Specific proteins
Is energy required for facilitated/carrier mediated diffusion, and why?
Energy is not required because the carrier only acts upon specific substrates
In terms of facilitated/carrier mediated diffusion:
How does the rate of the transport reach its maximum?
It is based on the number of the carriers available in the membrane
What is the difference between simple diffusion and facilitated Diffusion in terms of max?
Facilitated Diffusion can not rise greater than the v max but simple diffusion is proportional to the concentration of the diffusing substance so it has the ability to rise above the vmax
