Membrane Architecture and Fluidity
This models the biological membrane as a semifluid double layer where lipids and proteins are free to move laterally.
What is the Fluid Mosaic Model?
The type of transport that allows small nonpolar gas molecules like O2 and CO2 to move across the membrane down their gradient without energy or proteins.
What is simple diffusion?
Active transport mechanisms differ fundamentally from passive diffusion because active transport requires energy to move solutes in this direction relative to their gradient.
What is against (or up) their concentration gradient?
Membrane proteins that contain hydrophobic regions that span directly through the fatty acid core of the lipid bilayer.
What are integral membrane proteins
The general bulk transport process by which large particles or cells are engulfed into a vacuole by white blood cells.
The enzyme that actively moves phospholipids from one leaflet to the opposite leaflet by using ATP
The passive process where solutes cross the lipid bilayer down their concentration gradient using transmembrane channels or carriers.
What is facilitated diffusion
In a single cycle of the sodium-potassium pump Na+/K+ ATPase, this exact ratio and direction of ions are moved.
Membrane proteins that contain are covalently bonded to the phosphate heads of the lipid bylayer
What is peripheral membrane proteins
The endocytic process specifically responsible for taking in liquid droplets and extracellular fluid via small vesicles.
What is pinocytosis?
At body temperature, fatty acid tails that are longer affect membrane fluidity in this specific way.
What is decreasing membrane fluidity (making it less fluid/more rigid)?
When animal red blood cells are placed into a hypertonic salt solution, this physical shrinkage or wrinkling process occurs.
What is crenation
This class of active transport uses the energy stored in an established ion gradient rather than hydrolyzing ATP directly.
What is secondary active transport
A channel protein that opens or closes specifically when a chemical signal binds to its extracellular binding site
What is a ligand-gated channel
The transport process where a molecule enters one side of a cell in a vesicle, travels across the cytoplasm, and exits the opposite side.
What is transcytosis?
This carbohydrate-rich protective zone on the outer surface of the plasma membrane assists in cell recognition and shielding.
What is the glycocalyx (or cellular glycosylation)
Plant cells placed in a hypotonic environment maintain shape and structure due to the push of the central vacuole against the rigid cell wall, generating this force.
What is turgor pressure?
SGLT transporters in the kidneys bring both sodium and glucose into epithelial cells in the same direction, classifying SGLT as this type of transporter.
What is a symporter
Unlike open channel pores, carrier proteins transport solutes across the membrane by undergoing this specific structural process.
What is a shape (conformational) change
The bulk export process where intracellular vesicles fuse with the plasma membrane to release materials outside the cell.
What is exocytosis
Lateral movement of integral membrane proteins can be restricted or held in place by attaching to these internal cellular structures.
What are the cytoskeletal components
Steroid hormones cross membranes without helper proteins while glucose requires GLUT transporters because steroid hormones possess this biophysical property.
What is being nonpolar (hydrophobic)?
Continuous operation of the sodium-potassium pump in nerve cells maintains this key physiological electrical state.
What is the resting membrane potential
Transporters that move two or more different solute molecules across the membrane in opposite directions are categorized as these.
What are antiporters
The primary goal of selective cellular transport is maintaining internal balance, scientifically referred to as this.
what is homeostasis