Chapter 12, Problem 16Q

A.

Summary Introduction

To explain: The effect when lipid bilayer vesicles where Na⁺ pumps as sole membrane protein are suspended in a solution containing Na⁺ and K⁺ ions with a solution with same ionic composition inside them.

Introduction: Phospholipid bilayer is composed of two leaflets of amphipathic lipid molecules whose polar head groups are in contrast with the intra or extracellular aqueous phage, whereas the non-polar tails face each other constituting hydrophobic interior of the membrane in the vesicle. This vesicle is constructed in such a way where sodium pumps (Na⁺ pumps) act as a sole membrane protein and in each pump sodium ion (Na⁺) is transported in one way, and potassium ion (K⁺) is transported in other way in each pumping cycle.

B.

Summary Introduction

To explain: The effect to the lipid bilayer vesicle if ATP is added to the suspension of solution containing Na⁺ and K⁺ ions.

Introduction: Phospholipid bilayer is composed of two leaflets of amphipathic lipid molecules whose polar head groups are in contrast with the intra or extracellular aqueous phage, whereas the non-polar tails face each other constituting hydrophobic interior of the membrane in the vesicle. This vesicle is constructed in such a way where sodium pumps (Na⁺ pumps) act as a sole membrane protein and in each pump sodium ion (Na⁺) is transported in one way, and potassium ion (K⁺) is transported in other way in each pumping cycle.

C.

Summary Introduction

To explain: The effect when the ATP is added with outside as well as inside the lipid bilayer vesicle containing only Na⁺ and K⁺ ions is absent.

Introduction: Phospholipid bilayer is composed of two leaflets of amphipathic lipid molecules whose polar head groups are in contrast with the intra or extracellular aqueous phage, whereas the non-polar tails face each other constituting hydrophobic interior of the membrane in the vesicle. This vesicle is constructed in such a way where sodium pumps (Na⁺ pumps) act as a sole membrane protein and in each pump sodium ion (Na⁺) is transported in one way, and potassium ion (K⁺) is transported in other way in each pumping cycle.

D.

Summary Introduction

To explain: The effect when the concentrations of Na⁺ and K⁺ ion was with the same ionic composition, but half of the pump molecules embedded in the membrane of each vesicle were oriented the other way around, so that the normally cytosolic portions of these molecules faced the inside of the vesicles and ATP is added to the suspension.

Introduction: Phospholipid bilayer is composed of two leaflets of amphipathic lipid molecules whose polar head groups are in contrast with the intra or extracellular aqueous phage, whereas the non-polar tails face each other constituting hydrophobic interior of the membrane in the vesicle. This vesicle is constructed in such a way where sodium pumps (Na⁺ pumps) act as a sole membrane protein and in each pump sodium ion (Na⁺) is transported in one way, and potassium ion (K⁺) is transported in other way in each pumping cycle.

E.

Summary Introduction

To explain: The effect when ATP is added to the suspension of Na⁺ and K⁺ ions with a solution with same ionic composition inside them, but in addition to Na⁺ pumps, the membrane of the lipid bilayer vesicles also contains K⁺ leak channels.

Introduction: Phospholipid bilayer is composed of two leaflets of amphipathic lipid molecules whose polar head groups are in contrast with the intra or extracellular aqueous phage, whereas the non-polar tails face each other constituting hydrophobic interior of the membrane in the vesicle. This vesicle is constructed in such a way where sodium pumps (Na⁺ pumps) act as a sole membrane protein and in each pump sodium ion (Na⁺) is transported in one way, and potassium ion (K⁺) is transported in other way in each pumping cycle.