Chapter 11: Assignment Questions COMPLETE Flashcards
For a typical mammalian cell, [Na+] is higher:
in the extracellular space
in the cyotsol
in the extracellular space
For a typical mammalian cell, [K+] is higher:
in the extracellular fluid
in the cytosol
in the cytosol
For a typical mammalian cell, [Ca2+] is about 10,000-20,000 times higher _______ than in the other choice below.
in the extracellular fluid
in the cytosol
in the extracellular fluid
For a typical mammalian cell, pH is a bit higher (7.4 vs 7.2)
in the extracellular fluid
in the cytosol
in the extracellular fluid
Which can most readily cross a lipid bilayer?
non-polar molecules such as O2, CO2, steroid hormones, etc.
small, uncharged polar molecules such as H2O
large, uncharged polar molecules such as glucose
ions such as H+, Na+, K+, Ca2+, etc.
non-polar molecules such as O2, CO2, steroid hormones, etc.
Which can least readily cross a lipid bilayer?
non-polar molecules such as O2, CO2, steroid hormones, etc.
small, uncharged polar molecules such as H2O
large, uncharged polar molecules such as glucose
ions such as H+, Na+, K+, Ca2+, etc.
ions such as H+, Na+, K+, Ca2+, etc.
The limiting factor of simple diffusion of a molecule across a lipid bilayer is:
ability to interact with polar head groups of the membrane lipids
ability to interact with the hydrophobic interior of the lipid bilayer
ability to interact with the hydrophobic interior of the lipid bilayer
Which of these groups is hydrophobic?
-OH
-COO-
Correct!
-CH3
-H3N+
-CH3
Given that the direction of net movement of the solutes always down its concentration gradient, which way can the solute move?
into the cell
out of the cell
either in or out, depending on the concentration gradient
either in or out, depending on the concentration gradient
The kind of transporter/carrier- or channel-mediated movement that goes in the direction of the concentration gradient (from high to low) is called:
passive transport
secondary active transport
active transport
passive transport
Sometimes, a molecule has both a chemical gradient and an electrical (charge) gradient. That’s the:
chemical gradient
electrical gradient
voltage gradient
electrochemical gradient
electrochemical gradient
Which protein mediates active transport?
simple diffusion
channel-mediated
transporter mediated
active transport
active transport
Simple diffusion is:
active transport
movement against a concentration gradient
channel-mediated
transporter/carrier mediated
direct diffusion of a molecule across a lipid bilayer without involvement of a membrane protein
direct diffusion of a molecule across a lipid bilayer without involvement of a membrane protein
A researcher does an experiment that involves measuring rate of movement of a solute across a lipid bilayer. In the case of a certain solute, the movement rate keeps going up as the solute concentration increases and is never saturated (i.e. never reaches a point at which movement no longer increases even when solute concentration increases). This type of movement could be:
simple diffusion or channel mediated transport
carrier/transporter mediated facilitated diffusion
active transport
simple diffusion or channel mediated transport
When a protein couples ATP hydrolysis with “pumping” a solute across a lipid bilayer to create a chemical or electrochemical gradient for that solute, and then movement of that solute back across the lipid bilayer down its gradient drives movement of another solute, that’s:
secondary active transport
simple diffusion
facilitated diffusion
secondary active transport
A common feature of (coupled transporter, ATP-driven pump, light0driven pump) means of active transport is that:
they are coupled to some source of potential energy (e.g. light, chemical energy in bonds of ATP, potential energy of an electrochemical gradient)
they mediate simple diffusion
they mediate facilitated diffusion
they are coupled to some source of potential energy (e.g. light, chemical energy in bonds of ATP, potential energy of an electrochemical gradient)
a uniporter carries:
a molecule and ion in the same
a molecule and ion in different directions
a molecule one direction
a molecule one direction
an antiporter carries:
a molecule and ion in the same
a molecule and ion in different directions
a molecule one direction
a molecule and ion in different directions
a symporter carries:
a molecule and ion in the same
a molecule and ion in different directions
a molecule one direction
a molecule and ion in the same
In some tissues, a Na+/K+ pump creates a sodium gradient that then drives glucose uptake by the sodium-dependent glucose transporter. That’s an example of:
secondary active transport
facilitated diffusion
simple diffusion
secondary active transport
In other cases, there’s no need for active transport to create a sodium gradient, such as in the small intestine after ingestion of foods or beverages containing sodium. What would you say to that?
Neat!
impossible!
Neat!
The pH of a cell or subcellular compartment can be regulated by:
transport of H+ across a membrane by a proton pump or a Na+/H+ exchanger
movement of bicarbonate (HCO3-) across a membrane, such as by a chloride/bicarbonate exchanger
both are common mechanisms for regulation of pH!
both are common mechanisms for regulation of pH!
The carbonic anhydrase reaction is a key regulator of pH because:
The reaction it catalyzes (HCO3– + H+ ⇓⋄ H2O + CO2 ) can produce or consume protons, depending on the relative concentrations of the substrates/products
carbonic anhydrase is a proton pump
The reaction it catalyzes (HCO3– + H+ ⇓⋄ H2O + CO2 ) can produce or consume protons, depending on the relative concentrations of the substrates/products
On which side of the epithelial cell is glucose transport sodium dependent?
on the apical or brush-border side (facing the lumen of the small intestine, top of figure)
on the basolateral side (facing the extracellular fluid near the capillaries, bottom of figure)
on the apical or brush-border side (facing the lumen of the small intestine, top of figure)
On which side of the epithelial cell is glucose transport mediated by facilitated diffusion?
on the apical or brush-border side (facing the lumen of the small intestine, top of figure)
on the basolateral side (facing the extracellular fluid near the capillaries, bottom of figure)
on the basolateral side (facing the extracellular fluid near the capillaries, bottom of figure)