Chapter 4 Flashcards
Membrane Transport Significance
Nutrition and Respiration ;
Waste Removal
Export of Products
Signaling
Membrane Transport Problems
The non-polar barrier. Things that are polar cannot get in.
Passive Membrane Transport
No additional energy required. Require two things; Kinetic Energy and Concentration Gradient
Diffusion
Flux: A singe Particle; the random movement of a specific particle.
Net Flux Definition
The combination of every particles movement and the average of where they’re going. Will balance out.
Net Flux Information
Move from a higher concentration to a lower one. Reach equilibrium if given enough time.
Effect of Concentration
Will determine the direction of net flux. The stronger the concentration, the higher the rate.
Factors that affect Permeability
Membrane solubility of solute
Size of solute
Presence of membrane channels/carriers
Membrane Thickness
Factors that affect Permeability (Membrane solubility of solute)
Polarity. Non polars always are soluble to that plasma membrane
Factors that affect Permeability (Size Of Solute)
Smaller the solute, the better chance it has to get across. Non polar doesnt need help in terms of size
Factors that affect Permeability (Presence of membrane channels/carrierS)
Carrier has to be involved. More of these mean the membrane is more permable
Factors that affect Permeability (“Membrane Thickness”)
Whats around that membrane, can slow down the diffusion. Pneumonia, Water around aveoli when exchanging oxygen.
Effects of Surface Area (Passive Membrane TransporT)
More surface area means we have a better chance in terms of rate of diffusion
Electrical Driving Force (Passive Membrane Transport)
Only applies to charged particles
Opposites attract, likes repel. Sodium will be pulled in do to negative charge.
Electrical Driving Force (Passive Membrane Transport) (Increase of Concentration)
Increase of concentration on the outside causes electrical driving force to accelerate that.
Mechanisms of Passive Transport (Simple Diffusion)
The passive movement of particles across the membrane unassisted. No polar molecules and small polar molecules (slowly)
Mechanisms of Passive Transport (Diffusion Through Channels) Ungated Channels
Pores open all the time. Can go in any direction, only a tunnel. Allows diffusion to occur and most common things going through are H2O and K+
Mechanisms of Passive Transport (Diffusion Through Channels) Gated Channels
These have to have a specific sequence to open them
Mechanisms of Passive Transport (Gated Channels) Ligand Gated
Ligand, but acts like a messenger
Mechanisms of Passive Transport (Gated Channels) Ionotropic
Receptor for ligand and channel for ion are made of the same protein. Have a direct relationship
Mechanisms of Passive Transport (Gated Channels) Metabotropic
Peripheral, attached to the membrane. Receptor and channel are different proteins. Steps occur before it opens and can trigger further actions in cell
Mechanisms of Passive Transport (Gated Channels) Voltage Gated
Change in voltage to membrane. Certain ions are outside and cause a change to the membrane
Mechanisms of Passive Transport (Gated Channels) Mechanically-Gated
Are opened physically, something is physically making this channel open.
Mechanisms of Passive Transport (Gated Channels) Mechanically-Gated Examples
Stretch receptors, Stretching rubber bands and seeing the pores
Mechanisms of Passive Transport (Gated Channels) Temperature Gated
Temperature triggers this. We have hot and cold receptors. Changes in temp means ion channels opening and closing.
Mechanisms of Passive Transport (Facilitated Diffusion)
Transport protein. Physically assists particle from one side to the other. Diffusion through carrier protein. Binding causes morphological change.
Mechanisms of Passive Transport (Facilitated Diffusion) Powered by what?
Powered by KE. It’s bi-directional. Can go against concentration gradient.
Clinical Application : Insulin Dependent Glucose Transporters
Insulin binds to receptor on the outside. Binds and starts a cascade of things . Gets embedded within the membrane inside the cell. This then lets glucose get into the cell.