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Questions and Answers
Which of the following best describes the role of cell membranes?
Which of the following best describes the role of cell membranes?
- To provide mechanical strength and structure to the cell.
- To regulate the movement of chemicals in and out of the cell.
- To help with cell movement.
- All of the above (correct)
In the fluid mosaic model of the cell membrane, which biomolecules are primarily represented?
In the fluid mosaic model of the cell membrane, which biomolecules are primarily represented?
- Nucleic acids, lipids, and proteins
- Proteins, carbohydrates, and nucleic acids
- Carbohydrates, nucleic acids, and lipids
- Lipids, proteins, and carbohydrates (correct)
Why do the fatty acid tails of phospholipids orient toward each other in the cell membrane?
Why do the fatty acid tails of phospholipids orient toward each other in the cell membrane?
- They are polar and hydrophilic, attracting water molecules.
- They are charged and attract ions.
- They are non-polar and hydrophobic, avoiding water. (correct)
- They are hydrophilic and attract each other.
How does the final shape of a protein affect its role in the cell membrane?
How does the final shape of a protein affect its role in the cell membrane?
Which of the following molecules can diffuse directly through the lipid layer of the cell membrane?
Which of the following molecules can diffuse directly through the lipid layer of the cell membrane?
What type of molecules require assistance from carrier proteins to move across the cell membrane?
What type of molecules require assistance from carrier proteins to move across the cell membrane?
Which transport mechanism involves the movement of molecules from an area of high concentration to an area of low concentration without the use of energy?
Which transport mechanism involves the movement of molecules from an area of high concentration to an area of low concentration without the use of energy?
What distinguishes facilitated diffusion from simple diffusion?
What distinguishes facilitated diffusion from simple diffusion?
Why does passive diffusion through the lipid layer predominantly occur with gases and small, lipid-soluble molecules?
Why does passive diffusion through the lipid layer predominantly occur with gases and small, lipid-soluble molecules?
Why are channel proteins essential for the transport of hydrophilic ions across the cell membrane?
Why are channel proteins essential for the transport of hydrophilic ions across the cell membrane?
What is the primary driving force behind osmosis?
What is the primary driving force behind osmosis?
A cell is placed in a solution, and water moves into the cell, causing it to swell. What type of solution is the cell in?
A cell is placed in a solution, and water moves into the cell, causing it to swell. What type of solution is the cell in?
In which type of solution will a cell shrink due to water loss?
In which type of solution will a cell shrink due to water loss?
What happens to a cell placed in an isotonic solution?
What happens to a cell placed in an isotonic solution?
Which of the following transport mechanisms requires energy input?
Which of the following transport mechanisms requires energy input?
What is the primary difference between endocytosis and exocytosis?
What is the primary difference between endocytosis and exocytosis?
In a typical mammalian cell at rest what is the relative concentration of Sodium ($Na^+$) inside compared to outside?
In a typical mammalian cell at rest what is the relative concentration of Sodium ($Na^+$) inside compared to outside?
A scientist observes that a cell membrane is highly permeable to water but has limited permeability to sodium ions, what property of the membrane is responsible for this.
A scientist observes that a cell membrane is highly permeable to water but has limited permeability to sodium ions, what property of the membrane is responsible for this.
In a laboratory experiment, a researcher treats a cell with a chemical that disrupts the function of flippases. What direct effect would this have on the cell membrane?
In a laboratory experiment, a researcher treats a cell with a chemical that disrupts the function of flippases. What direct effect would this have on the cell membrane?
A researcher is studying the effect of temperature on membrane permeability. They observe that as the temperature decreases, the membrane becomes less permeable. What changes to the membrane lipids is the most likely explanation for this?
A researcher is studying the effect of temperature on membrane permeability. They observe that as the temperature decreases, the membrane becomes less permeable. What changes to the membrane lipids is the most likely explanation for this?
A cell maintains a high concentration of potassium ions inside the cell and a high concentration of sodium ions outside the cell. This is primarily achieved through:
A cell maintains a high concentration of potassium ions inside the cell and a high concentration of sodium ions outside the cell. This is primarily achieved through:
A cell engulfs a large particle by extending its plasma membrane around it and forming a large vesicle. What process is this?
A cell engulfs a large particle by extending its plasma membrane around it and forming a large vesicle. What process is this?
In exocytosis, what is the direct fate of the vesicle that fuses with the plasma membrane?
In exocytosis, what is the direct fate of the vesicle that fuses with the plasma membrane?
Following a meal, insulin stimulates glucose uptake by cells that are glucose transporter (GLUT4) dependent like muscle and adipose. What is the primary mechanism?
Following a meal, insulin stimulates glucose uptake by cells that are glucose transporter (GLUT4) dependent like muscle and adipose. What is the primary mechanism?
If a patient's red blood cells are placed in a solution and they burst, what does this indicate about the solution?
If a patient's red blood cells are placed in a solution and they burst, what does this indicate about the solution?
The kidneys maintain blood osmolarity through reabsorption from the lumen of the renal tubules. Which of the following transport will allow glucose reabsorption?
The kidneys maintain blood osmolarity through reabsorption from the lumen of the renal tubules. Which of the following transport will allow glucose reabsorption?
Which of the following is a primary characteristic of the plasma membrane that allows it to maintain different concentration gradients inside and outside the cell?
Which of the following is a primary characteristic of the plasma membrane that allows it to maintain different concentration gradients inside and outside the cell?
What is the direct role of cholesterol within animal cell membranes:
What is the direct role of cholesterol within animal cell membranes:
Which statement below accurately reflects the arrangement and properties of transmembrane proteins within the phospholipid bilayer:
Which statement below accurately reflects the arrangement and properties of transmembrane proteins within the phospholipid bilayer:
Which type of microscopy would best visualize the dynamic movement of lipids within a living cell membrane?
Which type of microscopy would best visualize the dynamic movement of lipids within a living cell membrane?
What is the immediate consequence if a cell's mechanisms for active transport suddenly fail?
What is the immediate consequence if a cell's mechanisms for active transport suddenly fail?
A cell membrane contains a transport protein that simultaneously moves sodium ions down their concentration gradient while transporting glucose into the cell against its concentration gradient. What type of transport is this example of?
A cell membrane contains a transport protein that simultaneously moves sodium ions down their concentration gradient while transporting glucose into the cell against its concentration gradient. What type of transport is this example of?
If a normal cell is placed in a solution with a very high concentration of a specific amino acid, it begins to swell. Which process is most likely responsible for this cell swelling?
If a normal cell is placed in a solution with a very high concentration of a specific amino acid, it begins to swell. Which process is most likely responsible for this cell swelling?
What happens to the rate of diffusion as the temperature increases?
What happens to the rate of diffusion as the temperature increases?
What is the role of the glycocalyx found on the external surface of some plasma membranes?
What is the role of the glycocalyx found on the external surface of some plasma membranes?
Which medical application is related to isotonic solutions?
Which medical application is related to isotonic solutions?
Which of the transport mechanisms does NOT directly involve a protein?
Which of the transport mechanisms does NOT directly involve a protein?
What can denature proteins?
What can denature proteins?
Flashcards
Biological molecules
Biological molecules
Basic building blocks of all cell parts.
Cell membrane composition
Cell membrane composition
Proteins, lipids, and some complex carbohydrates.
Functions of Cell Membrane
Functions of Cell Membrane
Gives strength, structure, helps with movement, controls cell volume
Fluid Mosaic Model
Fluid Mosaic Model
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Why fatty acid tails point inward
Why fatty acid tails point inward
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Protein's final shape
Protein's final shape
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Passive diffusion molecules
Passive diffusion molecules
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Simple diffusion
Simple diffusion
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Channel proteins necessity
Channel proteins necessity
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Osmosis
Osmosis
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Equal solute concentration
Equal solute concentration
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Less solute outside cell
Less solute outside cell
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More solute outside cell
More solute outside cell
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Active transport
Active transport
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Exocytosis
Exocytosis
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Study Notes
- Cell membranes' structure and function are explored
Building Blocks and Cell Membranes
- Molecules form basic units.
- Sugars combine to form carbohydrates.
- Amino acids combine to create proteins
- Fatty acids form lipid components
Cell Membranes
- Composed of proteins, lipids and complex carbohydrates.
- Provide structure, facilitate movement and modulate cell volume.
- Regulate chemical movement in/out of the cell.
Fluid Mosaic Model
- Cell membrane is based on it.
- Consists of the extracellular fluid, receptor protein, recognition protein, phospholipid, cholesterol, glycoprotein, transport protein, and protein filaments.
Membrane Composition and Lipid Bilayer
- Phospholipids feature hydrophilic heads and hydrophobic tails.
- Fatty acid tails face inward due to their non-polar nature, resulting in hydrophobic properties.
Membrane Components
- Proteins configuration dictates function.
Passive Transport
- Small uncharged molecules such as oxygen, carbon dioxide, nitrogen, water, glycerol and ethanol are able to undergo passive transport.
Passive/Simple Diffusion
- It is applicable to gases and lipid-soluble molecules given their non-polar nature analogous to lipid layers
Passive Transport
- Includes simple and facilitated diffusion and osmosis.
- Facilitated diffusion applies to hydrophilic ions using channel proteins.
- Ions necessitate channel proteins given their charge hindering passage thru non-polar lipid layers.
- Carrier proteins transport molecules like amino acids or sugars across the membrane, changing shape to facilitate transport.
Osmosis Highlighted
- Water diffusion process occurs across a semi-permeable membrane moving from high to low.
- Tonicity's impact in cells depend on surrounding fluids leading to isotonic, hypotonic and hypertonic conditions.
- Isotonic environments exhibit equal water movement in/out of cells.
- Hypotonic conditions lead to water influx and cell swelling.
- Hypertonic states cause water outflow leading to cell shrinkage.
Active Transport
- Energy is consumed.
- Includes active transport and exo/endocytosis.
- Active transport involves protein binding with ATP and Ca2+ to transport ions against their concentration gradients.
Cellular Osmolarity
- Intracellular fluid contains 108mM anions, 12mM Na+, 125mM K+, 5mM Cl-.
- Extracellular fluid consists of 120mM Na+, 5mM K+, 125mM Cl-.
- One osmolar solution indicates one mole of dissolved particles per liter.
Endocytosis
- Phagocytosis is a form of endocytosis where the cell membrane surrounds particles to bring them inside.
Endocytosis Explained
- Material is secreted from a cell, within a vesicle that fuses with the plasma membrane.
Glucose Transport
- Influenced by insulin with GLUT4 modulating glucose uptake in muscle, fat and myocardial tissues.
Study Questions
- The chemical nature of the cell membrane and water molecules should be taken into account to explain which mechanisms allow water molecules to traverse the structure.
- In 0.2M NaCl the questions, the solution osmorality, cell changes and final volume are the key to achieve equilibrium.
- The type of transport when glucose is translocated from the lumen of a kidney tubule into blood should be determined.
- Potential hypotonic, hypertonic and isotonic medical applications.
Osmosis and Diffusion
- Osmosis is special because it is a type of diffusion.
Recap
- Cell membranes comprise biological molecules.
- Molecular form and property define their functions.
- Membranes actively and passively govern material flow in cells.
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Description
Explore cell membrane structure, function, and composition. Learn about the building blocks of molecules, including carbohydrates, proteins, and lipids. Understand the Fluid Mosaic Model and the roles of phospholipids, proteins, and other components in membrane function and passive transport.
