Question 1

Ouabain, an effective inhibitor of Na⁺, K⁺-ATPase, exhibits all of the following characteristics EXCEPT:

Accepted Answer

Ouabain inhibits Na⁺, K⁺-ATPase by binding to the extracellular surface of the enzyme, but it does not specifically bind tightly to the enzyme/ATP complex.

Question 2

The System A for alanine transport into liver is a(n) ____ system that can be activated by ____ and ____.

Accepted Answer

Based on the information given in the question, the system for alanine transport into the liver is most likely a Na⁺-symport system. This means that alanine is transported into the liver cells together with Na+ ions, in the same direction. The system can be activated by the substrate (alanine) and hormones, which can trigger changes in the activity of the transporters. Therefore, choice A is the best answer. Choices B, C, and D are not accurate, as they do not match the information given in the question.

Question 3

Hydropathy plots for transport proteins are utilized to reveal:

Accepted Answer

Hydropathy plots are commonly used to identify stretches of amino acids that may form hydrophobic regions within a protein. In the case of transport proteins, these regions may be directly associated with the lipid bilayer and therefore important for the transport of substrate molecules across the membrane.

Question 4

Multiple Drug Resistant (MDR)-ATPase is a ____ repeat protein that uses ATP hydrolysis to actively transport a wide variety of drugs ____ the cell.

Accepted Answer

MDR-ATPase is a tandem repeat protein that uses ATP hydrolysis to actively transport drugs out of the cell, helping in drug resistance by expelling drugs from the cell.

Question 5

Secondary active transport across a membrane refers to

Accepted Answer

Secondary active transport involves the movement of a molecule against its concentration gradient, but unlike primary active transport, it is not directly powered by ATP. Instead, it relies on the energy stored in an ion gradient that has been established by a different transporter. This is the case in option A, making it the correct choice. Option B describes primary active transport, option C describes simple diffusion, option D is not a valid description of any transport process, and option E is not a valid answer.

Question 6

The transport of glutamine across a membrane was measured, and the results obtained are presented in the following table. What type of transport does Gln exhibit?

Accepted Answer

The transport of glutamine exhibits saturation kinetics and is not dependent on ATP. Therefore, it is most likely facilitated diffusion. The table shows that as the concentration of glutamine is increased, there is a corresponding increase in the rate of transport until a maximum rate (Vmax) is reached. This suggests that the transport is mediated by a carrier protein that becomes saturated at high concentrations of glutamine.

Question 7

In a typical Na⁺,K⁺-ATPase, _____ sodium ions are moved from the _____ of the cell while _____ potassium ions are moved from the _____ of the cell

Accepted Answer

In a typical Na⁺,K⁺-ATPase, 3 sodium ions are moved from the inside of the cell while 2 potassium ions are moved from the outside to the inside. This is because the pump binds with ATP and undergoes a conformational change that allows it to move sodium ions against their concentration gradient out of the cell and potassium ions against their concentration gradient into the cell. This is an important process in maintaining the electrochemical gradient across the cell membrane.

Question 8

Active transport is uniquely characterized by:

Accepted Answer

Active transport involves the movement of a molecule or ion against its concentration gradient, from an area of lower concentration to an area of higher concentration. This requires an input of energy to overcome the thermodynamic barrier created by the concentration gradient. In active transport, the energy input is tightly coupled to the transport process, with the energy being used to drive a thermodynamically unfavorable reaction. This is typically achieved through the hydrolysis of ATP, although other sources of energy, such as light or ion gradients, may also be used in some cases. Therefore, option D is the best choice.

Question 9

Pore-forming toxins solve the problem of a need to provide hydrogen-bonding partners for the polypeptide background N−H and C=O groups in the bilayer that lacks hydrogen-bond donors and acceptors by utilizing extensive:

Accepted Answer

The polypeptide background in the bilayer lacks hydrogen-bond donors and acceptors, which pore-forming toxins solve through the extensive formation of α-helices and β-sheets. They create a transmembrane barrel structure that provides hydrogen-bonding partners for the N−H and C=O groups of the polypeptide backbone, allowing them to span the bilayer.

Question 10

H⁺-transporting ATPases found in ____ break down bone during normal bone remodeling are of the ____ type of ATPases.

Accepted Answer

The question specifically mentions bone breakdown during normal bone remodeling, which is a function of osteoclasts. The ATPases involved in breaking down bone in osteoclasts are vacuolar (V-) ATPases.

Question 11

In the Na⁺, K⁺-ATPase mechanism, ATP is involved in all EXCEPT:

Accepted Answer

ATP transfers a phosphate group to the sodium ion to form sodium phosphate. ATP is not directly involved in the other steps listed.

Question 12

Secondary active transport is:

Accepted Answer

Secondary active transport involves the use of an ion gradient established by primary active transport (often using ATPase) to drive the transport of another molecule (like an amino acid or sugar) against its concentration gradient.

Question 13

Bacteriorhodopsin affects a light driven ____ proton transport that results in a proton gradient sufficient to drive ____.

Accepted Answer

Bacteriorhodopsin is a type of protein that is found in the purple membrane of the bacterium Halobacterium salinarum. It affects a light-driven proton transport that results in the generation of a proton gradient, which is sufficient to drive ATP synthesis. Therefore, the correct choice is B, which states that bacteriorhodopsin affects an outward light-driven proton transport that results in ATP synthesis.

Question 14

The Ca²⁺-ATPase structure is like many of the other active transport proteins in that it has all of the components EXCEPT:

Accepted Answer

The Ca²⁺-ATPase, like many other active transport proteins, indeed has a transmembrane domain of ten α-helical segments, a large cytoplasmic domain with a nucleotide-binding domain, a phosphorylation domain, and an actuator domain. These components are typical for the structure of active transport ATPases, indicating that all the given options are true components of such proteins.

Question 15

People with high blood pressure have high blood levels of an endogenous Na⁺, K⁺-ATPase ____ that results in ____ of sodium and calcium in cells lining the blood vessel wall.

Accepted Answer

The endogenous Na⁺, K⁺-ATPase inhibitor results in accumulation of sodium and calcium in cells lining the blood vessel wall, contributing to high blood pressure.

Question 16

Nearly all of the calcium ions in muscle are sequestered inside vesicles called:

Accepted Answer

Muscle cells store calcium ions inside vesicles called sarcoplasmic reticulum, which are specialized types of endoplasmic reticulum. Therefore, the correct answer is B.

Question 17

Discuss the preferred locations of different amino acids in transmembrane proteins.​

Accepted Answer

The answer of Discuss the preferred locations of different amino...

Question 18

Glucose transport across cell membranes varies depending upon blood glucose levels. When glucose levels are high, glucose transport exhibits saturation kinetics. When glucose concentrations are low, the transport of glucose across the membrane is dependent upon the sodium ion concentration. What types of transport is observed for glucose?

Accepted Answer

At high glucose concentrations, glucose transport exhibits saturation kinetics which is a type of facilitated diffusion. At low glucose concentrations, the transport of glucose across the membrane is dependent upon the sodium ion concentration, which is a type of secondary active transport. Therefore, the correct answer is A - facilitated diffusion at high [glucose], and secondary active transport at low [glucose].

Question 19

All are characteristic of the gastric proton pump EXCEPT:

Accepted Answer

The gastric proton pump does not require dietary components to create a gradient; it functions by actively transporting H+ ions into the stomach in exchange for K+ ions, using energy from ATP hydrolysis.

Question 20

Muscle Ca²⁺-ATPase resembles Na⁺, K⁺-ATPase in many ways EXCEPT:

Accepted Answer

Muscle Ca^2+ ATPase (SERCA) resides on the sarcoplasmic reticulum, whereas Na^+/K^+ ATPase is located on the plasma membrane, not the sarcoplasmic reticulum. This is the key difference among the options provided.

Quiz 9: Membranes and Membrane Transport

Ouabain, an effective inhibitor of Na⁺, K⁺-ATPase, exhibits all of the following characteristics EXCEPT:

The System A for alanine transport into liver is a(n) system that can be activated by and .

Hydropathy plots for transport proteins are utilized to reveal:

Multiple Drug Resistant (MDR) -ATPase is a repeat protein that uses ATP hydrolysis to actively transport a wide variety of drugs the cell.

Secondary active transport across a membrane refers to

The transport of glutamine across a membrane was measured, and the results obtained are presented in the following table. What type of transport does Gln exhibit?

In a typical Na⁺,K⁺-ATPase, ___ sodium ions are moved from the _ of the cell while _ potassium ions are moved from the ___ of the cell

Active transport is uniquely characterized by:

Pore-forming toxins solve the problem of a need to provide hydrogen-bonding partners for the polypeptide background N−H and C=O groups in the bilayer that lacks hydrogen-bond donors and acceptors by utilizing extensive:

H⁺-transporting ATPases found in break down bone during normal bone remodeling are of the type of ATPases.

In the Na⁺, K⁺-ATPase mechanism, ATP is involved in all EXCEPT:

Secondary active transport is:

Bacteriorhodopsin affects a light driven proton transport that results in a proton gradient sufficient to drive .

The Ca²⁺-ATPase structure is like many of the other active transport proteins in that it has all of the components EXCEPT:

People with high blood pressure have high blood levels of an endogenous Na⁺, K⁺-ATPase that results in of sodium and calcium in cells lining the blood vessel wall.

Nearly all of the calcium ions in muscle are sequestered inside vesicles called:

Discuss the preferred locations of different amino acids in transmembrane proteins.

All are characteristic of the gastric proton pump EXCEPT:

Muscle Ca²⁺-ATPase resembles Na⁺, K⁺-ATPase in many ways EXCEPT:

Quiz 9: Membranes and Membrane Transport

Ouabain, an effective inhibitor of Na+, K+-ATPase, exhibits all of the following characteristics EXCEPT:

The System A for alanine transport into liver is a(n) ____ system that can be activated by ____ and ____.

Hydropathy plots for transport proteins are utilized to reveal:

Multiple Drug Resistant (MDR) -ATPase is a ____ repeat protein that uses ATP hydrolysis to actively transport a wide variety of drugs ____ the cell.

Secondary active transport across a membrane refers to

The transport of glutamine across a membrane was measured, and the results obtained are presented in the following table. What type of transport does Gln exhibit?

In a typical Na+,K+-ATPase, _____ sodium ions are moved from the _____ of the cell while _____ potassium ions are moved from the _____ of the cell

Active transport is uniquely characterized by:

Pore-forming toxins solve the problem of a need to provide hydrogen-bonding partners for the polypeptide background N−H and C=O groups in the bilayer that lacks hydrogen-bond donors and acceptors by utilizing extensive:

H+-transporting ATPases found in ____ break down bone during normal bone remodeling are of the ____ type of ATPases.

In the Na+, K+-ATPase mechanism, ATP is involved in all EXCEPT:

Secondary active transport is:

Bacteriorhodopsin affects a light driven ____ proton transport that results in a proton gradient sufficient to drive ____.

The Ca2+-ATPase structure is like many of the other active transport proteins in that it has all of the components EXCEPT:

People with high blood pressure have high blood levels of an endogenous Na+, K+-ATPase ____ that results in ____ of sodium and calcium in cells lining the blood vessel wall.

Nearly all of the calcium ions in muscle are sequestered inside vesicles called:

Discuss the preferred locations of different amino acids in transmembrane proteins.​

All are characteristic of the gastric proton pump EXCEPT:

Muscle Ca2+-ATPase resembles Na+, K+-ATPase in many ways EXCEPT:

Ouabain, an effective inhibitor of Na⁺, K⁺-ATPase, exhibits all of the following characteristics EXCEPT:

The System A for alanine transport into liver is a(n) system that can be activated by and .

Multiple Drug Resistant (MDR) -ATPase is a repeat protein that uses ATP hydrolysis to actively transport a wide variety of drugs the cell.

In a typical Na⁺,K⁺-ATPase, ___ sodium ions are moved from the _ of the cell while _ potassium ions are moved from the ___ of the cell

H⁺-transporting ATPases found in break down bone during normal bone remodeling are of the type of ATPases.

In the Na⁺, K⁺-ATPase mechanism, ATP is involved in all EXCEPT:

Bacteriorhodopsin affects a light driven proton transport that results in a proton gradient sufficient to drive .

The Ca²⁺-ATPase structure is like many of the other active transport proteins in that it has all of the components EXCEPT:

People with high blood pressure have high blood levels of an endogenous Na⁺, K⁺-ATPase that results in of sodium and calcium in cells lining the blood vessel wall.

Discuss the preferred locations of different amino acids in transmembrane proteins.

Muscle Ca²⁺-ATPase resembles Na⁺, K⁺-ATPase in many ways EXCEPT: