p.3
Proton Motive Force in Indirect Transport
What is the role of proton motive force in indirect transport?
It stores energy in the concentration gradient of protons, which can drive processes like bacterial flagellum movement.
p.3
Na+-K+ ATPase Pump Functionality
What maintains the sodium concentration gradient necessary for sodium-glucose symport?
The sodium-potassium ATPase, which pumps sodium ions out of the cell against their concentration gradient.
p.3
Group Translocation in Bacteria
What is group translocation in bacteria?
A transport system where the solute is chemically modified during transport, such as glucose being converted to glucose-6-phosphate.
p.1
Na+-K+ ATPase Pump Functionality
What are the two conformations of the Na+-K+ ATPase pump?
E1 state (high affinity for sodium ions) and E2 state (high affinity for potassium ions).
p.2
Proton Motive Force in Indirect Transport
What is the function of the H+ pumps found in plant vacuoles and animal lysosomes?
To actively transport H+ from the cytosol to the lumen to regulate pH.
p.5
Iron Uptake Mechanisms in Cells
What is required for the synthesis of new receptors in cholesterol uptake?
Phosphatidic acid (PA) is needed for synthesizing new receptors.
p.2
Calcium Ion Transport and Muscle Relaxation
What is the role of the Ca2+ ATPase pump in muscle relaxation?
It actively transports Ca2+ back to the sarcoplasmic reticulum.
p.1
Na+-K+ ATPase Pump Functionality
What is the role of phosphorylation in the Na+-K+ ATPase pump?
Phosphorylation triggers a change in conformation of the pump, allowing it to transport ions.
p.3
Indirect ATP-Dependent Transport
What is indirect ATP-dependent transport?
Transport that does not directly depend on ATP hydrolysis but relies on other energy sources, such as sodium concentration gradients.
p.5
Iron Uptake Mechanisms in Cells
What role do cell-surface transferrin receptors play?
They facilitate the uptake of iron by binding to transferrin.
p.3
Light-Driven Active Transport in Archaea
What is light-driven active transport?
A process where light serves as the energy source to transport ions, such as in Halobacterium halobium using bacteriorhodopsin.
p.2
Direct ATP-Dependent Transport
What does the E1 state of the Ca2+ ATPase pump have an affinity for?
Calcium ions, opened towards the cytosol.
p.5
Iron Uptake Mechanisms in Cells
What is the consequence of class 5 cholesterol uptake abnormalities?
Receptors fail to dissociate from LDL particles in the endosome, leading to degradation instead of recycling.
p.1
Direct ATP-Dependent Transport
What is the energy source for direct ATP-dependent transport?
ATP hydrolysis, which produces ADP and inorganic phosphate (Pi).
p.1
Direct ATP-Dependent Transport
What is the function of ATPase in the context of active transport?
ATPase catalyzes the hydrolysis of ATP and acts as a transport protein.
p.2
Direct ATP-Dependent Transport
What happens to the E1 conformation of the pump during phosphorylation?
It changes to E2 conformation.
p.3
Group Translocation in Bacteria
What high-energy compound is involved in group translocation?
Phosphoenolpyruvate (PEP).
p.2
Active Transport vs Passive Transport
What types of substrates can the ABC superfamily transport?
Ions, polysaccharides, lipids, amino acids, peptides, and proteins.
p.3
Sodium-Glucose Symport Mechanism
How does sodium-glucose symport function?
It actively transports glucose into intestinal cells using the sodium concentration gradient, where two sodium ions drive the transport of one glucose molecule.
p.1
Active Transport vs Passive Transport
What role do carrier proteins play in active transport?
Carrier proteins change their conformation to transport molecules across the membrane.
p.2
Active Transport vs Passive Transport
What are the two types of domains in the ABC superfamily?
Two T domains (integral proteins) and two A domains (peripheral proteins).
p.3
Group Translocation in Bacteria
What happens to glucose during group translocation?
It is phosphorylated to become glucose-6-phosphate after transport.
p.5
Iron Uptake Mechanisms in Cells
What is transferrin?
A blood plasma glycoprotein that transports iron.
p.1
Active Transport vs Passive Transport
What is the main difference between passive and active transport?
Active transport requires energy and moves substances against their concentration gradient, while passive transport does not require energy and moves substances along their concentration gradient.
p.1
Na+-K+ ATPase Pump Functionality
What is the significance of the sodium concentration gradient maintained by the Na+-K+ ATPase pump?
It stores energy (sodium motive force) needed for other metabolic processes in the cell.
p.1
Na+-K+ ATPase Pump Functionality
What happens during the E1 state of the Na+-K+ ATPase pump?
The pump faces the cytosolic side, and three sodium ions bind before ATP is hydrolyzed.
p.5
Iron Uptake Mechanisms in Cells
What are the two forms of transferrin?
Transferrin (with iron) and apotransferrin (without iron).
