WorksheetsCell Transport
Total questions: 20
Worksheet time: 10mins
Transporters allow solutes to cross a membrane at much faster rates than do channels.
True
False
The plasma membrane of many animal cells contains open K+ channels, yet the K+ concentration in the cytosol is much higher than outside the cell.
True
False
The membrane potential of an axon temporarily becomes more negative when an action potential excites it.
True
False
The interiors of the ER, Golgi apparatus, endosomes, and lysosomes communicate with each other in which of the following ways?
By small vesicles that bud off of one organelle and fuse with another
By open pores that allow ions to exit and enter the organelles
They do not communicate with one another.
By excreting hormones and other small signaling molecules
The movement of materials from the plasma membrane, through endosomes, and then to lysosomes describes which type of pathway?
Secretory pathway
Endocytic pathway
None of the above
What protein can assemble into a basket-like network that gives budding vesicles their shape?
Dynamin
Clathrin
Actin
Myosin
The regulated exocytosis pathway of the Golgi apparatus operates continually in all eucaryotic cells.
True
False
Which of the following is NOT true of receptor-mediated endocytosis?
In receptor-mediated endocytosis, extracellular substances are internalized in clathrin-coated vesicles.
. Low-density lipoproteins (LDLs) are taken into cells by receptor mediated endocytosis.
. In receptor-mediated endocytosis, internalized vesicles fuse with lysosomes, which then mature into endosomes.
Defective LDL receptor proteins may contribute to the development of atherosclerosis.
Which cellular compartment acts as the main sorting station for extracellular cargo molecules taken up by endocytosis?
Transport vesicles
The Golgi apparatus
Endosomes
Lysosomes
Lipid bilayers are highly impermeable to:
carbon dioxide.
water.
Na+ and Cl-
ethanol.
What is the difference between transporters and channels?
Transporters discriminate between solutes mainly on the basis of size and electric charge; channels bind their solutes with great specificity in the same way an enzyme binds its substrate.
Channels discriminate between solutes mainly on the basis of size and electric charge; transporters bind their solutes with great specificity in the same way an enzyme binds its substrate.
Channels will allow the passage of any solute as long as it has an electrical charge; transporters bind their solutes with great specificity in the same way an enzyme binds its substrate.
When glucose moves across a phospholipid bilayer by passive transport, which factor determines the direction of its transport?
The concentrations of glucose on either side of the membrane
The charge difference across the membrane
The amount of energy available to fuel the transport process
. All of the above
The Na+ -K+ pump in the plasma membrane of animal cells uses the energy from ATP hydrolysis to pump sodium and potassium ions against their electrochemical gradients. In which direction are the ions pumped across the membrane?
K+out and Na+ in
K+ in and Na+ out
Na+ and K+ both out
Na+ and K+ both in
Which of the following statements is true about the concentration of calcium ions in cells?
Calcium levels are kept high in the cytosol compared to outside the cell
Calcium levels are kept low in the cytosol compared to outside the cell.
Calcium levels are kept the same in the cytosol compared to outside the cell.
Which term describes a coupled transporter that moves both solutes in the same direction across a membrane?
Antiport
Symport
Uniport
When Na+ channels are opened in an animal cell, what happens to the membrane potential?
It stays the same
It becomes less negative
It becomes more negative
During an action potential, which of the following actions does not help return the membrane to its resting potential?
The opening of voltage-gated Na+ channels
The opening of voltage-gated K+ channels
The inactivation of voltage-gated Na+ channels
What is the name of the specialized junction between a neuron and a target cell?
Synapse
Dendrite
. Nerve terminal
When an action potential reaches a nerve terminal, what type of voltage-gated channels are opened and result in the fusion of synaptic vesicles with the cell membrane?
Na+
Ca2+
K+
Cl'
1.The plasma membrane is highly impermeable to all charged molecules.
True
False
