Biology: The Dynamic Science (MindTap Course List)
4th Edition
ISBN: 9781305389892
Author: Peter J. Russell, Paul E. Hertz, Beverly McMillan
Publisher: Cengage Learning
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Textbook Question
Chapter 5, Problem 1TYK
In the fluid mosaic model:
plasma membrane proteins orient their hydrophilic sides toward the internal bilayer.
phospholipids often flip-flop between the inner and outer layers.
the mosaic refers to proteins attached to the underlying cytoskeleton.
the fluid refers to the phospholipid bilayer.
the mosaic refers to the symmetry of the internal membrane proteins and sterols.
Expert Solution & Answer
Summary Introduction
Introduction:
The membrane of the cell is composed of the phospholipid bilayer and proteins. The structure of the membrane is explained by the fluid-mosaic model proposed by Singer and Nicolson. The proteins are distributed unevenly in the bilayer of the lipids.
Answer to Problem 1TYK
Correct answer:
The fluid in the fluid-mosaic refers to the bilayer of phospholipids.
Explanation of Solution
Explanation for the correct answer:
Option (d) is given that thephospholipid bilayer is the fluid part of the membrane. The cellular membrane is formed of the phospholipids and proteins. The fluidity of the membrane is imparted by the phospholipid bilayer, which is amphipathic in nature. Hence, option (d) is correct.
Explanation for the incorrect answers:
Option (a) is given that the hydrophilic sides of the membrane proteins are present towards the internal layer. The proteins present in the membrane are hydrophilic in nature and are present towards the cytosolic or outer sides. They are attracted towards water and span the membrane. So, it is an incorrect option.
Option (b) is given that phospholipids often flip-flop in the layer. The phospholipid layer of the membrane is continuous and uniform. The lipid molecules move sideways rather than flip-flop movement across the inner and outer sides of the membrane. So, it is an incorrect option.
Option (c) is given that the protein attached to the cytoskeleton forms the mosaic part. The mosaic portion of the membrane is formed by the protein. Proteins span the membrane and are present on both the outer and inner sides of the membrane. The inner proteins are attached to the cytoskeleton. So, it is an incorrect option.
Option (e) is given that the mosaic is formed by the symmetry of the internal proteins and sterols. The mosaic region comprises the total proteins present in the membrane. Proteins are unevenly distributed in the membrane. So, it is an incorrect option.
Hence, options (a), (b), (c), and (e) are incorrect.
Conclusion
Therefore, it is concluded that the fluid part of the membrane is formed by the phospholipid bilayer, while the mosaic region is formed by the total protein of the membrane.
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Students have asked these similar questions
Draw and label a cell lipid bilayer and diagram how the following transport processes take place: passive diffusion of oxygen into the cell, facilitated diffusion of potassium into the cell, active transport of sucrose into the cell. Using different symbols (circles for oxygen, squares for sucrose, and triangles for potassium ions), show the relative concentrations (gradients) of these substances on the inside and outside of the cell. For example, to show that oxygen enters the cell by going “down” its gradient, you would draw more circles on the outside of the cell than inside the cell. Be sure to show and label membrane proteins when appropriate, and show the electric membrane potential using “+”s (pluses) on one side and “-”s (minuses) on the other side of the membrane. Also show the proton pump which uses ATP as a source of energy.
Which of the following best describes a biological membrane?
two layers of phospholipids with proteins embedded between the two layers
two layers of phospholipids (with opposite orientations of the phospholipids in each layer) with each layer covered on the outside with proteins
two layers of phospholipids with proteins either spanning the layers or on the surface of the layers
a fluid structure in which phospholipids and proteins move freely between sides of the membrane
a mixture of covalently linked phospholipids and proteins that determines which solutes can cross the membrane and which cannot
Draw a lipid bilayer, and focus on three lipids that are on the same side of the
membrane. Color in the areas where you expect the hydrophobic interactions,
and in another color, shade in the areas that are hydrophilic.
Draw another lipid bilayer, and for this one, include two membrane proteins. One
of them should be an integral membrane protein and the other one a peripheral
membrane protein. Label the lipid bilayer, the side the faces the cytoplasm and
the side that faces outside the cell. Also label the two proteins, and shade in the
areas where you predict that you would find hydrophobic amino acids and
hydrophilic amino acids.
Chapter 5 Solutions
Biology: The Dynamic Science (MindTap Course List)
Ch. 5.1 - Describe the fluid mosaic model for membrane...Ch. 5.1 - Give two examples each of integral proteins and...Ch. 5.2 - What is the difference between passive and active...Ch. 5.2 - Prob. 2SBCh. 5.3 - Prob. 1SBCh. 5.3 - Prob. 2SBCh. 5.4 - Prob. 1SBCh. 5.4 - Prob. 2SBCh. 5.5 - Prob. 1SBCh. 5.5 - Prob. 2SB
Ch. 5 - In the fluid mosaic model: plasma membrane...Ch. 5 - Which of the following statements is false?...Ch. 5 - The freeze-fracture technique demonstrated: a....Ch. 5 - A characteristic of carrier molecules in a primary...Ch. 5 - A driving ion moving through a membrane channel in...Ch. 5 - Phagocytosis illustrates which phenomenon? a....Ch. 5 - Place in order the following events of...Ch. 5 - Prob. 8TYKCh. 5 - Which of the following statements is true for the...Ch. 5 - Using the principle of diffusion, a dialysis...Ch. 5 - Discuss Concepts The bacterium Vibrio cholera...Ch. 5 - Prob. 12TYKCh. 5 - Prob. 13TYKCh. 5 - Prob. 15TYKCh. 5 - Some cancer cells are insensitive to typical...Ch. 5 - Some cancer cells are insensitive to typical...
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