56 Questions
What is the main function of membrane proteins in a cell?
Provide mechanical linkage for other proteins on either side of the membranes
Which type of membrane proteins are permanently bound to the lipid bilayer?
Integral Proteins
What is the role of transport proteins in the cell membrane?
Facilitate movement of ions and small molecules across the membrane
Which proteins sense a ligand on one side of the membrane and transmit a signal to the other side?
Membrane receptor proteins
How do membrane receptor proteins serve as a connection between the cell's internal and external environments?
By acting as a signaling link between internal and external environments
What is the ratio of the intracellular compartment to the total body fluids?
2/3
Which type of cell is around 100 µm in size?
Fat cell
What is the main function of the cell membrane?
Regulate the exchange of nutrients, ions, and hormones with its environment
Which fluid compartments are further subdivided into interstitial fluid and plasma?
Extracellular fluid
What does the Darrow-Yannet Diagram explain?
Changes in the body fluid compartments with excessive salt intake, sweating, dehydration, etc.
Which type of cell is the longest based on the provided information?
Smooth muscle cell
What is the primary driving force for water movement in osmosis?
High solute concentration
How does Aquaporins (AQPs) affect water permeability in cells?
Increase water permeability
What is the role of Anti-diuretic hormone (ADH) in the kidneys regarding water reabsorption?
Increase water reabsorption
How is osmolarity defined in a solution?
Concentration of solute particles per liter of solution
In a 1mM NaCl solution, what is the osmolarity?
2 mOsm/L NaCl
What does osmotic pressure represent in osmosis?
Mechanical pressure to produce water flow equal to the osmotic flow
What does the Permeability (P) equation describe?
The relationship between the diffusion coefficient and the partition coefficient
How does the concentration gradient affect the rate of diffusion?
Higher concentration gradient leads to faster diffusion
What role do carrier proteins play in facilitated diffusion?
They facilitate solute movement by binding molecules on one side and releasing on the other side
How does membrane thickness impact the rate of diffusion?
Thicker membrane leads to slower diffusion
What happens if a substance is impermeable to a membrane?
No diffusion occurs
How does increased membrane surface area affect diffusion?
Enhances diffusion rate
What is the main function of ion channels in the cell membrane?
Generate electrical currents
Which type of ion channel opens when physical forces cause the channel gates to open?
Mechanically-gated channels
What initiates the opening of voltage-gated ion channels?
Change in electrical potential
Which type of transporter facilitates the movement of two or more molecules across the plasma membrane in the same direction?
Symporters
What is the function of antiporters (exchangers) in membrane transport?
Move ions and molecules in opposite directions
Which membrane transport process requires no carrier protein or channel?
Simple Diffusion
What factors affect the rate of diffusion through a cell membrane according to Fick’s Law?
Membrane surface area and lipid composition
What does the Stokes-Einstein Equation describe in relation to molecular diffusion?
Inverse relationship between molecular radius and diffusion coefficient
How do chemically-gated ion channels generate electrical signals?
From binding specific molecules like neurotransmitters or hormones
Which type of transporter requires energy to move molecules across the membrane?
Symporters
What is the primary driving force for the movement of 3 Na+ ions out of the cell and 2 K+ ions into the cell by the Na-K ATPase pump?
Hydrolysis of one ATP molecule
Which type of ATPase pump is responsible for maintaining ionic gradients by moving ions against their gradients?
P-type ATPase
What is the most abundant pump in eukaryotic cells that is classified as a P-type ATPase?
Na-K Pump
Which drugs are known to block the activity of the Na-K Pump?
Digitalis and ouabain
What is the primary function of V-ATPases in cellular processes?
Coupling ATP hydrolysis to pump protons
Which of the following pumps calcium from the cytoplasm into the sarcoplasmic reticulum in muscle cells?
SERCA Pump
What is the main role of integral membrane proteins in the cell membrane?
Mediate the selective movement of ions across the membrane
Which type of membrane proteins are temporarily associated with the lipid bilayer or with integral membrane proteins?
Peripheral Proteins
What is the primary function of carrier proteins in the cell membrane?
Facilitate the selective movement of ions and small molecules across the membrane
How do channel proteins differ from carrier proteins in membrane transport?
Channel proteins facilitate the movement of molecules through a pore
In what way do membrane receptor proteins act as intermediaries between a cell's internal and external environments?
By sensing ligands and transmitting signals across the membrane
What proportion of the total body fluid compartments does the intracellular compartment account for?
2/3
Which cell type listed is among the smallest based on the provided information?
Red blood cell
What is the primary function of the cell (plasma) membrane?
Regulate exchange of nutrients, ions, and hormones
What is the primary role of the Darrow-Yannet Diagram in explaining body fluid compartments?
Explain osmolarity changes with salt intake
Which of the following is NOT a function of the cell (plasma) membrane?
Synthesize hormones
How do interstitial fluid and plasma relate to cells?
They are subcategories of extracellular fluid that interact with cells
What is the main function of ATP-binding cassette (ABC) transporters?
Consume ATP while transporting molecules across membranes
Where is the SGLT transporter primarily active in transporting sodium and glucose?
Intestine or kidney
What is the consequence of the multidrug resistance (MDR) pump being highly expressed in bacteria and cancer cells?
Increases the excretion of drugs resulting in a loss of potency
What role does Na-K ATPase play in secondary active transport involving the SGLT transporter?
Creates a high-affinity site for glucose binding
How does glucose binding change carrier conformation in secondary active transport by the SGLT protein?
It ensures binding sites face the intracellular fluid
What is the primary source of energy used by symporters like the SGLT protein for secondary active transport?
Na-K ATPase gradient
Test your knowledge on the structure and function of membrane proteins. Learn about integral proteins, peripheral proteins, membrane transporters, membrane enzymes, and membrane receptors.
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