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Questions and Answers
What is the function of a transport protein?
What is the function of a transport protein?
allow solute molecules to enter the cell.
Which of these cannot rapidly pass directly through the phospholipids of the plasma membrane?
Which of these cannot rapidly pass directly through the phospholipids of the plasma membrane?
- Water (correct)
- Hydrogen ion (correct)
- Oxygen
- Glucose (correct)
What is the function of cholesterol?
What is the function of cholesterol?
helps to stabilize the structure of the plasma membrane (phospholipids)
Which of the following best describes the structure of a biological membrane?
Which of the following best describes the structure of a biological membrane?
The fluid mosaic model of the membrane proposed that membranes ________.
The fluid mosaic model of the membrane proposed that membranes ________.
A primary function of cholesterol in the plasma membranes of some animals is to ________.
A primary function of cholesterol in the plasma membranes of some animals is to ________.
An integral membrane protein would have to be ________.
An integral membrane protein would have to be ________.
How do unsaturated fatty acids help keep any membrane more fluid at lower temperatures?
How do unsaturated fatty acids help keep any membrane more fluid at lower temperatures?
In facilitated diffusion, what is the role of the transport protein?
In facilitated diffusion, what is the role of the transport protein?
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?
Water passes quickly through cell membranes because _______.
Water passes quickly through cell membranes because _______.
Which of the following factors does not affect membrane permeability?
Which of the following factors does not affect membrane permeability?
How can a lipid be distinguished from a sugar?
How can a lipid be distinguished from a sugar?
True or false? Osmosis is a type of diffusion.
True or false? Osmosis is a type of diffusion.
What property of dishwashing liquid (detergent) makes it useful to wash grease from pans?
What property of dishwashing liquid (detergent) makes it useful to wash grease from pans?
Which of the following particles could diffuse easily through a cell membrane?
Which of the following particles could diffuse easily through a cell membrane?
True or false? The water-soluble portion of a phospholipid is the polar head, which generally consists of a glycerol molecule linked to a phosphate group.
True or false? The water-soluble portion of a phospholipid is the polar head, which generally consists of a glycerol molecule linked to a phosphate group.
If a red blood cell is placed in a salt solution and bursts, what is the tonicity of the solution relative to the interior of the cell?
If a red blood cell is placed in a salt solution and bursts, what is the tonicity of the solution relative to the interior of the cell?
What name is given to the process by which water crosses a selectively permeable membrane?
What name is given to the process by which water crosses a selectively permeable membrane?
What kind of solution is a cell in if there is a greater concentration of solute outside of the cell?
What kind of solution is a cell in if there is a greater concentration of solute outside of the cell?
You know that a cell is in a(n) _______ solution because the cell _______.
You know that a cell is in a(n) _______ solution because the cell _______.
You know that this cell is in a(n) _______ solution because it _______.
You know that this cell is in a(n) _______ solution because it _______.
Submerging a red blood cell in a hypertonic solution will result in _______.
Submerging a red blood cell in a hypertonic solution will result in _______.
A patient has had a serious accident and lost a lot of blood. In an attempt to replenish body fluids, distilled water equal to the volume of blood lost is transferred directly into one of his veins. What will be the most probable result of this transfusion?
A patient has had a serious accident and lost a lot of blood. In an attempt to replenish body fluids, distilled water equal to the volume of blood lost is transferred directly into one of his veins. What will be the most probable result of this transfusion?
A red blood cell placed in a hypertonic solution will shrink in a process called crenation. A red blood cell placed in a hypotonic solution will swell and potentially burst in a process called hemolysis. To prevent crenation or hemolysis, a cell must be placed in an isotonic solution such as 0.9% (m/v) NaCl or 5.0% (m/v) glucose. Indicate whether crenation, hemolysis, or neither will occur in Solution A: 3.21% (m/v) NaCl; Solution B: 1.65% (m/v) glucose; Solution C: distilled H2O; Solution D: 6.97% (m/v) glucose; Solution E: 5.0% (m/v) glucose and 0.9% (m/v) NaCl.
A red blood cell placed in a hypertonic solution will shrink in a process called crenation. A red blood cell placed in a hypotonic solution will swell and potentially burst in a process called hemolysis. To prevent crenation or hemolysis, a cell must be placed in an isotonic solution such as 0.9% (m/v) NaCl or 5.0% (m/v) glucose. Indicate whether crenation, hemolysis, or neither will occur in Solution A: 3.21% (m/v) NaCl; Solution B: 1.65% (m/v) glucose; Solution C: distilled H2O; Solution D: 6.97% (m/v) glucose; Solution E: 5.0% (m/v) glucose and 0.9% (m/v) NaCl.
Which of the following statements is TRUE with regard to this animation of active transport?
Which of the following statements is TRUE with regard to this animation of active transport?
Active and passive transport of solutes across a membrane typically differ in which of the following ways?
Active and passive transport of solutes across a membrane typically differ in which of the following ways?
The movement of glucose into a cell against a concentration gradient is most likely to be accomplished by which of the following?
The movement of glucose into a cell against a concentration gradient is most likely to be accomplished by which of the following?
What is the voltage across a membrane called?
What is the voltage across a membrane called?
The sodium-potassium pump is called an electrogenic pump because it _______.
The sodium-potassium pump is called an electrogenic pump because it _______.
Which of the following would increase the electrochemical gradient across a membrane?
Which of the following would increase the electrochemical gradient across a membrane?
Endocytosis moves materials _______ a cell via _______.
Endocytosis moves materials _______ a cell via _______.
You can recognize the process of pinocytosis when _______.
You can recognize the process of pinocytosis when _______.
A white blood cell engulfing a bacterium is an example of _______.
A white blood cell engulfing a bacterium is an example of _______.
Which of the following correctly describes some aspect of exocytosis or endocytosis?
Which of the following correctly describes some aspect of exocytosis or endocytosis?
The difference between pinocytosis and receptor-mediated endocytosis is that _______.
The difference between pinocytosis and receptor-mediated endocytosis is that _______.
A signal transduction pathway is initiated when a _______ binds to a receptor.
A signal transduction pathway is initiated when a _______ binds to a receptor.
A signal molecule is also known as a(n) _______.
A signal molecule is also known as a(n) _______.
Which of these is the second of the three stages of cell signaling?
Which of these is the second of the three stages of cell signaling?
Which of the following is a substance that acts at a long distance from the site at which it is secreted?
Which of the following is a substance that acts at a long distance from the site at which it is secreted?
Why are there often so many steps between the original signal event and the cell's response?
Why are there often so many steps between the original signal event and the cell's response?
Which of the following sequences is/are correct?
Which of the following sequences is/are correct?
Immediately following binding of a growth factor, an activated receptor would most likely stimulate ________.
Immediately following binding of a growth factor, an activated receptor would most likely stimulate ________.
Following activation of a receptor, which sequence below represents the correct order in which components will be involved in a signaling pathway that utilizes the second messenger cAMP?
Following activation of a receptor, which sequence below represents the correct order in which components will be involved in a signaling pathway that utilizes the second messenger cAMP?
Which of the following enzymes adds a phosphate group to target proteins?
Which of the following enzymes adds a phosphate group to target proteins?
Which of the following is least likely to be important in holding the components of a biological membrane together?
Which of the following is least likely to be important in holding the components of a biological membrane together?
Which of the following factors would tend to increase membrane fluidity?
Which of the following factors would tend to increase membrane fluidity?
Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because __________.
Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because __________.
Lipid-soluble signaling molecules, such as aldosterone, cross the membranes of all cells but affect ONLY target cells because __________.
Lipid-soluble signaling molecules, such as aldosterone, cross the membranes of all cells but affect ONLY target cells because __________.
Which of the following molecular movements is due to diffusion or osmosis?
Which of the following molecular movements is due to diffusion or osmosis?
Which statement is correct?
Which statement is correct?
Select the correct statement about osmosis.
Select the correct statement about osmosis.
What are the functions of signal transduction pathways?
What are the functions of signal transduction pathways?
Select the statement that correctly distinguishes between relay proteins and second messengers in signal transduction pathways.
Select the statement that correctly distinguishes between relay proteins and second messengers in signal transduction pathways.
Flashcards
Transport proteins
Transport proteins
Proteins embedded in the cell membrane that help move molecules across the membrane.
Osmosis
Osmosis
The movement of water across a semipermeable membrane from an area of high water concentration to an area of low water concentration.
Facilitated diffusion
Facilitated diffusion
A type of passive transport where molecules move across a membrane with the help of transport proteins.
Hypotonic solution
Hypotonic solution
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Hypertonic solution
Hypertonic solution
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Isotonic solution
Isotonic solution
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Active transport
Active transport
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Sodium-potassium pump
Sodium-potassium pump
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Hormone
Hormone
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Signal transduction pathway
Signal transduction pathway
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Endocytosis
Endocytosis
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Exocytosis
Exocytosis
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Pinocytosis
Pinocytosis
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Phagocytosis
Phagocytosis
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Membrane potential
Membrane potential
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Membrane permeability
Membrane permeability
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Lipid-soluble molecule
Lipid-soluble molecule
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Phospholipid bilayer
Phospholipid bilayer
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Cholesterol
Cholesterol
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Integral membrane protein
Integral membrane protein
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Unsaturated fatty acid
Unsaturated fatty acid
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Fluid mosaic model
Fluid mosaic model
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Membrane fluidity
Membrane fluidity
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Metabolism
Metabolism
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Receptor
Receptor
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Ligand
Ligand
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Kinase
Kinase
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Phosphorylation cascade
Phosphorylation cascade
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Relay protein
Relay protein
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Second messenger
Second messenger
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Non-covalent interactions
Non-covalent interactions
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Study Notes
Transport Proteins and Membrane Structure
- Transport proteins facilitate the movement of solute molecules into cells.
- Certain substances, such as water, glucose, and hydrogen ions, cannot pass through phospholipids of the plasma membrane rapidly.
- Cholesterol stabilizes the structure of phospholipid membranes and maintains fluidity under varying temperatures.
Fluid Mosaic Model
- Biological membranes consist of two layers of phospholipids, incorporated with proteins that span or are attached to the membrane surface.
- The fluid mosaic model describes membranes as protein molecules embedded in a fluid bilayer.
Membrane Permeability and Transport
- Integral membrane proteins are amphipathic, featuring both hydrophilic and hydrophobic regions.
- Unsaturated fatty acids introduce kinks in lipid tails, enhancing membrane fluidity at lower temperatures.
- Facilitated diffusion involves transport proteins creating hydrophilic pathways for solute movement.
Osmosis and Tonicity
- Osmosis refers to the diffusion of water through selectively permeable membranes, facilitating the movement of water in relation to solute concentration.
- A hypotonic solution has a lower solute concentration than a cell, leading to swelling due to water influx.
- A hypertonic solution causes cells to lose water and shrink (crenation).
- Isotonic solutions prevent osmotic imbalance, maintaining cell shape and size.
Active Transport and Signaling Pathways
- Active transport, such as the sodium-potassium pump, requires ATP energy to move ions against their concentration gradients.
- Signal transduction pathways initiate responses when a ligand binds to a receptor, triggering a cascade of intracellular reactions.
- Each step in a signaling cascade amplifies the signal for greater cellular response.
Types of Endocytosis and Exocytosis
- Endocytosis transports materials into cells through vesicles, while exocytosis expels materials, altering membrane surface area.
- Pinocytosis is the non-selective uptake of fluids, while phagocytosis specifically involves engulfing larger particles, such as bacteria.
Signal Transduction and Hormones
- Hormones act as long-distance signaling molecules, affecting only target cells equipped with specific receptors.
- Kinases add phosphate groups to target proteins, playing a critical role in transduction pathways.
- Phosphorylation cascades amplify signals after receptor activation.
Key Definitions and Concepts
- Membrane potential refers to the voltage across a cell membrane, crucial for cellular function.
- Lipid-soluble molecules can cross membranes but affect only target cells with specific receptors.
- Diffusion movement includes the behavior of water in hypertonic environments, highlighting the dynamics of osmosis.
- Relay proteins and second messengers work together within signaling pathways to relay signals from receptors to effectors.
Membrane Composition and Functionality
- Membranes rely on non-covalent interactions to maintain structure, emphasizing lipid and protein dynamics.
- Increasing the proportion of unsaturated phospholipids enhances membrane fluidity, crucial for many cellular processes.
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Description
Test your knowledge on the functions and components of the cell membrane with this quiz. From transport proteins to the role of cholesterol, assess your understanding of how molecules interact with the plasma membrane. Perfect for students studying cellular biology!
