Chapter 10 Flashcards
What kind of molecules are most likely to diffuse across a membrane? What kind is harder to pass across? Which kind won’t at all?
Hydrophobic molecules go through the membrane easily. Large, uncharged molecules have a harder time going through it. Ions do not cross at.
What are the two types of diffusion?
What do they do?
(They are also types of transport)
Simple diffusion: Small noncharged molecules pass between the phospholipids to enter or leave the cell, moving from areas of high concentration to areas of low concentration
(Nonpolar compounds only, down concentration gradient)
Facilitated diffusion: The passive movement of molecules across the cell membrane with help of a membrane protein. It is utilized by molecules that are unable to cross the phospholipid bilayer freely
(Down electrochemical gradient)
What are the six types of transport?
Simple diffusion
Facilitated diffusion
Primary active transport
Secondary active transport
Ion channel
Ionophore-mediated ion transport
What is the primary active transport?
Goes against the electrochemical gradient.
The transport of molecules against a concentration gradient through the use of energy generated by ATP
What is the secondary active transport?
Goes against the electrochemical gradient, driven by ion moving down its gradient.
The transport of two distinct molecules across a membrane using energy in other forms than ATP.
What is the ion channel?
Goes down the electrochemical gradient; and may be gated by a ligand or ion.
Protein molecules that span across the cell membrane allowing the passage of ions from one side of the membrane to the other.
What is ionophore-mediated ion transport?
Goes down the electrochemical gradient
Can bind non-covalently with ions and can assist in their transport across the cell membrane
What are the three general classes of transport systems?
Uniport
Symport
Antiport
*Symport and antiport are cotransports
What is the uniport transport system?
When a type of molecule moves across a membrane, through carrier proteins, independent of other molecules; diffusion is called uniport
One molecule goes through
What is the symport transport system?
Proteins that simultaneously transport two molecules across a membrane in the same direction
Both molecules go across in the same way
What is the antiport transport system?
A process in which two different species of solutes or ions are pushed across a membrane in opposite directions.
What is the P-type transporter? What does phosphorylation do?
P-type ATPases undergo phosphorylation during their catalytic cycle. They are cation transporters that are reversibly phosphorylated by ATP as part of the transport cycle.
Phosphorylation forces a conformational change that is central to the movement of the cation across the membrane.
What is the F-type transporter? What are its two domains and what do they do?
F-type ATPases are reversible, ATP-driven proton pumps.
Peripheral Domain (F1): Has 3 alpha subunits, 3 beta subunits, one delta unit, and a central shaft joined to the integral domain through epsilon.
Integral Domain (F0): Has multiple copies of the c subunit, one a subunit, and two b subunits. F0 provides a transmembrane channel through which protons are pumped, about 4 each ATP hydrolyzed on the beta subunit of F1.
F1 and F0 mechanisms are coupled
What is the reversibility of F-type ATPases?
ATP-driven proton transporter can also catalyze ATP synthesis as protons flow down their electrochemical gradient. This is the central reaction in the processes of oxidative phosphorylation and photophosphorylation.
What is the V-type transporter?
What does the vesicle pump do?
What is the transport subunit?
What is the peripheral protein component?
Proton pumps are responsible for acidifying intracellular compartments in many organisms.
“vesicle” pumps force protons into organelles like vacuoles, endosomes, and the Golgi complex.
Transport subunit is transmembrane protein
Peripheral protein component is the ATPase
