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According to the fluid-mosaic model of the plasma membrane,
a. protein and phospholipids form a regular, repeating structure.
b. the membrane is a rigid structure.
c. phospholipids form a double layer, with the polar parts facing each other.
d. proteins are free to move within a double layer of phospholipids.
To determine:
Characteristic features of the fluid mosaic model of the plasma membrane.
Introduction:
The fluid mosaic model is composed of lipid bilayer. The lipid bilayer provides elasticity and fluidity to the membrane. It contains the phospholipid, cholesterol, protein, and carbohydrates. The plasma membrane is amphipathic in nature, in which the hydrophobic tails face each other whereas the hydrophilic region faces the cytosol. There are two kinds of proteins present in the membrane- integral and peripheral membrane proteins.
Answer to Problem 1RA
Correct answer:
The fluid mosaic model of the plasma membrane is that the proteins are free to move within a double layer of phospholipids. Therefore, option (d) is correct.
Explanation of Solution
Explanation for the correct answer:
Option (d) is given that proteins are free to move within a double layer of phospholipid. The fluid mosaic model of the plasma membrane describes the membrane as a combination of phospholipid, cholesterol, and protein which give the membrane the fluid nature. The plasma membrane is not a rigid entity hence allows free movement of integral proteins within the lipid bilayer. Hence, option (d) is correct.
Explanation for the incorrect answer:
Option (a) protein and phospholipid form a regular, repeating structure. The two leaflets of the membrane are asymmetric in nature. Both the leaflets are composed of different proteins and lipids, which give a distinct identity to the membrane. Therefore, option (a) is incorrect.
Option (b) the membrane is a rigid structure. The membrane is not a rigid structure. It is a lipid bilayer which is composed of various phospholipids, cholesterol, and proteins. They are composed of amphiphilic molecules. They have a hydrophilic phosphate and a hydrophobic tail. Therefore, option (b) is incorrect.
Option (c) phospholipid forms a double layer, with the polar parts facing each other. The phospholipid forms a two-layered cell membrane, where the hydrophobic tails face each other and the hydrophilic heads or the polar parts face out. Therefore, option (c) is incorrect.
Hence, options (b), (a), and (c) are incorrect.
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Chapter 3 Solutions
HUMAN PHYSIOLOGY-ACCESS >CUSTOM<
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Concepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax College