The Na+/K+ pump is:
a) cytosolic enzyme;
b) membrane protein with enzyme activity;
c) membrane lipid.
The Na+/K+ pump is found:
a) in all types of cells;
b) in the excitable cells only;
c) in the human excitable cells.
The Na+/K+ pump is a type of:
a) passive ion transporter;
b) facilitated ion channel;
c) active ion transporter.
Does the Na+/K+ pump require an energy source?
a) yes, it hydrolyses adenosine triphosphate;
b) no, ions are driven by concentration gradients;
c) yes, it uses redox reactions in the annular lipid molecules.
What are the operation modes of the Na+/K+ pump?
a) electrogenic and non-electrogenic;
b) transmembrane and intracellular;
c) passive and active.
Describe the directions of ion transport through the Na+/K+ pump:
a) moves Na+ and K+ ions out of the cell;
b) moves Na+ out, and K+ in;
c) moves Na+ in, and K+ out.
. The Na+/K+ pump is found in:
a) cellular membranes;
b) cellular membrane and the membrane of the endoplasm reticulum;
c) nuclear and cellular membranes.
Which of the following transport processes is considered an active transport?
a) the transfer of substance (molecules, ions) from area with high concentration into area of lower concentration;
b) the transfer of substance (molecules, ions) irregardless of the direction of the concentration gradient;
c) the transfer of substance (molecules, ions) from area with low concentration into area of higher concentration;
According the type of energy supply, the active membrane transport is divided into:
a) primary and secondary;
b) simport and antiport;
c) active and passive.
Which of the following statements does not hold for primary active transport?
transmembrane transport of inorganic ions;
transmembrane transport of organic molecules;
uses energy from ATP.
In the electrogenic regime the sodium – potassiumpump:
a) moves one negative charge out of the cell;
b) moves one positive charge out of the cell;
c) moves three positive charges in, for two positive charges out.
Which of the following statements refer to the primary active transmembrane transport?
a) transport of organic molecules;
b) uses the energy of the concentration gradient of Na+;
c) involves the active transport of: Na+, K+, Ca2+, H+, Mg2+, Cl-, and bicarbonate ions.
The secondary active transport is carried through:
a) membrane protein carriers;
b) transmembrane ion channels;
c) spontaneously formed (and vanishing) membrane pores.
The Na+/I- symporter, which transports iodine into the thyroid gland, cannot distinguish between non-radioactive (I-127) and radioactive (I-131) iodine. How could this be explained?
a) radioactive and non-radioactive iodine have the same physical properties;
b) radioactive and non-radioactive iodine have the same number of neutrons;
c) radioactive and non-radioactive iodine have the same chemical properties.
What type of membrane transport delivers iodide into the thyroid gland? a) passive transport;
a) passive transport;
b) primary active transport;
c) secondary active transport.
What is the direct driving force for the transmembrane transport of iodide?
a) energy from the hydrolysis of ATP;
b) the electrochemical gradient of Na+ ions;
c) the concentration gradient of Na+ ions.
Antiport is defined as:
a) coupled membrane transport, where substances move in the same direction;
b) coupled membrane transport, where substances move in opposite directions;
c) ion channel that allows ions to move only in one direction.
The operational mode of the thyroid Na+/I- symporter is as follows:
a) 2 Na+ ions move in, for each I- ion moving in;
b) 2 Na+ ions move out, for each I- ion moving in;
c) 3 Na+ ions move in, for 2 I- ions moving out.
An example for secondary active transport is:
a) the Ca2+ pump;
b) the Na+/I- symporter;
c) the K+ leak channel.
The electrogenic mode of operation of the Na+/K+ pump is as follows:
a) 2 Na+ ions move out, for 3 K+ ions moving in;
b) 3 Na+ ions move out, for 2 K+ ions moving in;
c) 3 Na+ ions move in, for 2 K+ moving out;
Transmembrane transport of substances against their electrochemical gradient, that does not use direct coupling of ATP is called:
When substances are transported across the membrane through specialised protein molecules, the process is described as:
a) simple diffusion;
b) uniport or cotransport;
c) protein transport.
When substances use protein carrier molecules to cross the membrane, the process is described as:
b) protein-lipid transport;
c) facilitated diffusion.
What type of membrane transport involves the accumulation of iodine in the follicular cells of the thyroid gland?
b) secondary-active;
c) facilitated passive.
a) primary-active;
The primary active membrane transport is carried by:
a) aquaporins;
b) ion channels;
c) ion pumps.
The bi-directional secondary active transport is called:
a) simport;
b) antiport;
c) uniport.
