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Questions and Answers
Which of the following types of molecules are the major structural components of the cell membrane?
Which of the following types of molecules are the major structural components of the cell membrane?
What is represented by Figure 7.1 that corresponds to peripheral proteins?
What is represented by Figure 7.1 that corresponds to peripheral proteins?
D
What is represented by Figure 7.1 that corresponds to cholesterol?
What is represented by Figure 7.1 that corresponds to cholesterol?
E
What does A in Figure 7.1 correspond to?
What does A in Figure 7.1 correspond to?
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What does C in Figure 7.1 represent?
What does C in Figure 7.1 represent?
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What does B in Figure 7.1 correspond to?
What does B in Figure 7.1 correspond to?
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When biological membranes are frozen and then fractured, they tend to break along the middle of the bilayer. The best explanation for this is that:
When biological membranes are frozen and then fractured, they tend to break along the middle of the bilayer. The best explanation for this is that:
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The presence of cholesterol in the plasma membranes of some animals enables the membrane to:
The presence of cholesterol in the plasma membranes of some animals enables the membrane to:
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According to the fluid mosaic model of cell membranes, which is a true statement about membrane phospholipids?
According to the fluid mosaic model of cell membranes, which is a true statement about membrane phospholipids?
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How do the membranes of winter wheat remain fluid in extremely cold temperatures?
How do the membranes of winter wheat remain fluid in extremely cold temperatures?
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In order for a protein to be an integral membrane protein, it would have to be:
In order for a protein to be an integral membrane protein, it would have to be:
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When a membrane is freeze-fractured, what are the bumps seen on the fractured surface of the membrane?
When a membrane is freeze-fractured, what are the bumps seen on the fractured surface of the membrane?
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Why do unsaturated fatty acids help keep membranes more fluid at lower temperatures?
Why do unsaturated fatty acids help keep membranes more fluid at lower temperatures?
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Which of the following is true of integral membrane proteins?
Which of the following is true of integral membrane proteins?
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What is the most important function for the glycoproteins and glycolipids of animal cell membranes?
What is the most important function for the glycoproteins and glycolipids of animal cell membranes?
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An animal cell lacking oligosaccharides on its plasma membrane would likely be impaired in which function?
An animal cell lacking oligosaccharides on its plasma membrane would likely be impaired in which function?
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In the years since the proposal of the fluid mosaic model, what observation has been added to the model?
In the years since the proposal of the fluid mosaic model, what observation has been added to the model?
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Which of the following span the phospholipid bilayer, usually multiple times?
Which of the following span the phospholipid bilayer, usually multiple times?
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Which of these are not embedded in the lipid bilayer at all?
Which of these are not embedded in the lipid bilayer at all?
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Which of these are attached to the extracellular matrix?
Which of these are attached to the extracellular matrix?
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Which of these often serve as receptors or cell recognition molecules on cell surfaces?
Which of these often serve as receptors or cell recognition molecules on cell surfaces?
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The formulation of a model for a structure or for a process serves which of the following purposes?
The formulation of a model for a structure or for a process serves which of the following purposes?
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Cell membranes are asymmetrical. What is the most likely explanation?
Cell membranes are asymmetrical. What is the most likely explanation?
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What is true of the evolution of cell membranes?
What is true of the evolution of cell membranes?
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Why are lipids and proteins free to move laterally in membranes?
Why are lipids and proteins free to move laterally in membranes?
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What kinds of molecules pass through a cell membrane most easily?
What kinds of molecules pass through a cell membrane most easily?
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Which of the following is a characteristic feature of a carrier protein in a plasma membrane?
Which of the following is a characteristic feature of a carrier protein in a plasma membrane?
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After a membrane freezes and then thaws, why does it often become leaky to solutes?
After a membrane freezes and then thaws, why does it often become leaky to solutes?
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Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly?
Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly?
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Which of the following statements is correct about diffusion?
Which of the following statements is correct about diffusion?
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Why does water pass quickly through cell membranes?
Why does water pass quickly through cell membranes?
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Chloride ion channels in cell membranes are classified as what type of molecules?
Chloride ion channels in cell membranes are classified as what type of molecules?
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What problem can arise for someone with nonfunctional chloride channels in cystic fibrosis?
What problem can arise for someone with nonfunctional chloride channels in cystic fibrosis?
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What aspect of cystic fibrosis would affect the fertility of a young male child?
What aspect of cystic fibrosis would affect the fertility of a young male child?
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Initially, in terms of tonicity, the solution in side A with respect to that in side B is?
Initially, in terms of tonicity, the solution in side A with respect to that in side B is?
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After the system reaches equilibrium, what changes are observed?
After the system reaches equilibrium, what changes are observed?
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What is the most probable result of transfusing distilled water into a patient who has lost a lot of blood?
What is the most probable result of transfusing distilled water into a patient who has lost a lot of blood?
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What can be deduced about the cells of celery stalks that become stiff in fresh water?
What can be deduced about the cells of celery stalks that become stiff in fresh water?
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A cell whose cytoplasm has a concentration of 0.02 molar glucose is placed in a solution of the same concentration. The tonicity of the external solution is described as?
A cell whose cytoplasm has a concentration of 0.02 molar glucose is placed in a solution of the same concentration. The tonicity of the external solution is described as?
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At the beginning of the experiment in Figure 7.3, side A is described as?
At the beginning of the experiment in Figure 7.3, side A is described as?
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If you examine side A after 3 days, what should you find?
If you examine side A after 3 days, what should you find?
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Which statement correctly describes the normal tonicity conditions for typical plant and animal cells?
Which statement correctly describes the normal tonicity conditions for typical plant and animal cells?
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In Figure 7.4, which line represents the bag that contained a solution isotonic to the 0.6 molar solution at the beginning of the experiment?
In Figure 7.4, which line represents the bag that contained a solution isotonic to the 0.6 molar solution at the beginning of the experiment?
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In Figure 7.4, which line represents the bag with the highest initial concentration of sucrose?
In Figure 7.4, which line represents the bag with the highest initial concentration of sucrose?
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In Figure 7.4, which line or lines represent(s) bags that contain a solution that is hypertonic at the end of 60 minutes?
In Figure 7.4, which line or lines represent(s) bags that contain a solution that is hypertonic at the end of 60 minutes?
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Which factor determines whether a molecule enters the cytoplasm of specific target cells when designing a new drug?
Which factor determines whether a molecule enters the cytoplasm of specific target cells when designing a new drug?
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In which of the following would there be the greatest need for osmoregulation?
In which of the following would there be the greatest need for osmoregulation?
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When a plant cell is submerged in a very hypotonic solution, what is likely to occur?
When a plant cell is submerged in a very hypotonic solution, what is likely to occur?
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Which membrane activities require energy from ATP hydrolysis?
Which membrane activities require energy from ATP hydrolysis?
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What are the membrane structures that function in active transport?
What are the membrane structures that function in active transport?
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What transport mechanism is most probably functioning in the intestinal cells to rapidly move glucose?
What transport mechanism is most probably functioning in the intestinal cells to rapidly move glucose?
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What is the voltage across a membrane called?
What is the voltage across a membrane called?
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In most cells, electrochemical gradients of many ions across the plasma membrane are likely maintained by?
In most cells, electrochemical gradients of many ions across the plasma membrane are likely maintained by?
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Why is the sodium-potassium pump considered an electrogenic pump?
Why is the sodium-potassium pump considered an electrogenic pump?
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If a membrane protein in an animal cell is involved in the cotransport of glucose and sodium ions, what is most likely true?
If a membrane protein in an animal cell is involved in the cotransport of glucose and sodium ions, what is most likely true?
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The movement of potassium into an animal cell requires?
The movement of potassium into an animal cell requires?
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Ions diffuse across membranes down their:
Ions diffuse across membranes down their:
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What mechanisms do plants use to load sucrose into specialized cells in the veins of leaves?
What mechanisms do plants use to load sucrose into specialized cells in the veins of leaves?
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Where will the ATP binding site be on a sodium-potassium pump protein first synthesized in the rough ER?
Where will the ATP binding site be on a sodium-potassium pump protein first synthesized in the rough ER?
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What does the presence of proton pumps in various kingdoms suggest?
What does the presence of proton pumps in various kingdoms suggest?
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Which development has improved the outcome of serious viral diseases resulting in dehydration?
Which development has improved the outcome of serious viral diseases resulting in dehydration?
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What process would an organism with a cell wall find most difficult to execute?
What process would an organism with a cell wall find most difficult to execute?
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Through what process do white blood cells engulf bacteria?
Through what process do white blood cells engulf bacteria?
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Familial hypercholesterolemia is characterized by?
Familial hypercholesterolemia is characterized by?
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What is the difference between pinocytosis and receptor-mediated endocytosis?
What is the difference between pinocytosis and receptor-mediated endocytosis?
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In receptor-mediated endocytosis, where do receptor molecules end up after endocytosis?
In receptor-mediated endocytosis, where do receptor molecules end up after endocytosis?
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How do the membranes of a eukaryotic cell vary?
How do the membranes of a eukaryotic cell vary?
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According to the fluid mosaic model of membrane structure, proteins of the membrane are mostly?
According to the fluid mosaic model of membrane structure, proteins of the membrane are mostly?
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Which factor would tend to increase membrane fluidity?
Which factor would tend to increase membrane fluidity?
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Which of the following processes includes all others?
Which of the following processes includes all others?
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Study Notes
Cell Membrane Components
- Major structural components: phospholipids and proteins
- Integral membrane proteins usually span the bilayer multiple times
- Peripheral proteins are not embedded within the lipid bilayer
Membrane Structure and Properties
- Cholesterol maintains membrane fluidity, especially at lower temperatures
- Unsaturated fatty acids keep membranes fluid in cold environments due to kinks in their tails
- Membranes are asymmetrical because proteins are allocated as they are packaged in the ER and Golgi
Membrane Functionality
- Cell membranes permit the lateral movement of phospholipids
- Glycoproteins and glycolipids are essential for cell recognition and signaling
- Na+ ions require ATP for active transport out of cells
Transport Mechanisms
- Small, hydrophobic molecules pass membranes easily
- Facilitated diffusion allows rapid transport of glucose in intestinal cells
- Aquaporins enable quick water transport across membranes
Tonicity and Osmoregulation
- Isotonic solutions maintain balance in cells, while hypotonic solutions can cause swelling
- Plant cells become turgid in hypotonic solutions, while animal cells can burst
- Osmoregulation is crucial for terrestrial animals to manage water balance
Ion Channels and Pumps
- Electrochemical gradients across membranes are maintained by pumps like the sodium-potassium pump
- Cotransport proteins facilitate the movement of ions and molecules across membranes
- Proton pumps play a key role in various cellular processes across all kingdoms
Disease Implications
- Cystic fibrosis results from defective chloride channels, leading to secretions buildup
- Familial hypercholesterolemia involves defective LDL receptors affecting cholesterol uptake
Endocytosis Processes
- Phagocytosis is utilized by white blood cells to engulf bacteria
- Pinocytosis differs from receptor-mediated endocytosis by only bringing in fluids instead of specific molecules
Membrane Fluidity Factors
- Greater proportions of unsaturated phospholipids increase membrane fluidity
- Membrane structures are influenced by the unique proteins present in specific membranes
Membrane Model
- The fluid mosaic model describes proteins embedded within a lipid bilayer
- New observations suggest that the concentration of protein molecules in membranes is generally higher than previously thought
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Dive into the vital concepts of cell membranes with these flashcards from Chapter 7 of Mastering Biology. Test your knowledge on key components such as phospholipids, proteins, and the extracellular matrix. Perfect for reinforcing your understanding of cellular structures.
