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Questions and Answers
What is the primary difference between isotonic, hypertonic, and hypotonic solutions?
What is the primary difference between isotonic, hypertonic, and hypotonic solutions?
The primary difference is the concentration of solutes compared to another solution. Isotonic solutions have equal solute concentration, hypertonic solutions have higher solute concentration, and hypotonic solutions have lower solute concentration.
What is the significance of membrane permeability in cell transport, and how does it impact the movement of substances?
What is the significance of membrane permeability in cell transport, and how does it impact the movement of substances?
Membrane permeability is significant because it determines which substances can pass through the membrane freely, such as water, oxygen, and carbon dioxide, and which substances require the use of membrane pumps or channels, such as proteins, ions, and glucose.
Distinguish between active and passive transport, and provide examples of each.
Distinguish between active and passive transport, and provide examples of each.
Active transport requires energy and involves the use of membrane pumps or vesicles to move substances across the cell membrane, whereas passive transport does not require energy and is powered by concentration gradients. Examples of passive transport include simple diffusion, facilitated diffusion, and osmosis, while active transport involves membrane pumps and bulk transport using vesicles.
What is the primary difference between diffusion and osmosis?
What is the primary difference between diffusion and osmosis?
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How do concentration gradients drive the movement of substances across the cell membrane, and what is the role of membrane pumps in this process?
How do concentration gradients drive the movement of substances across the cell membrane, and what is the role of membrane pumps in this process?
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Compare and contrast facilitated diffusion and active transport, highlighting the key similarities and differences between the two mechanisms.
Compare and contrast facilitated diffusion and active transport, highlighting the key similarities and differences between the two mechanisms.
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Describe the role of monomers and polymers in the structure and function of biological molecules, providing examples of each.
Describe the role of monomers and polymers in the structure and function of biological molecules, providing examples of each.
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Explain the significance of dynamic equilibrium in the context of cell membrane transport, highlighting its importance in maintaining cellular homeostasis.
Explain the significance of dynamic equilibrium in the context of cell membrane transport, highlighting its importance in maintaining cellular homeostasis.
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Compare and contrast the different types of bulk transport mechanisms, including exocytosis, endocytosis, pinocytosis, and phagocytosis.
Compare and contrast the different types of bulk transport mechanisms, including exocytosis, endocytosis, pinocytosis, and phagocytosis.
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Discuss the importance of carbohydrates, lipids, proteins, and nucleic acids in cellular function, highlighting their unique roles and characteristics.
Discuss the importance of carbohydrates, lipids, proteins, and nucleic acids in cellular function, highlighting their unique roles and characteristics.
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Study Notes
Cell Transport
- Isotonic: a solution with equal solute concentration to another solution
- Hypertonic: a solution with higher solute concentration than other solutions
- Hypotonic: a solution with lower solute concentration than other solutions
Membrane Permeability
- Cell membranes are selectively permeable
- Some substances (e.g. water, oxygen, carbon dioxide) can pass through the membrane freely
- Other substances (e.g. proteins, ions like K+ and Na+, glucose) cannot pass through the membrane and require membrane pumps or channels
Types of Transport Across Cell Membrane
Passive Transport
- Does not require energy
- Powered by concentration gradients
- Examples: simple diffusion, facilitated diffusion, and osmosis
Active Transport
- Requires energy
- Example: membrane pumps, bulk transport using vesicles
Passive Transport: Diffusion versus Osmosis
- Diffusion: passive movement of particles from high concentration to low concentration (down concentration gradient)
- Osmosis: passive movement of water molecules across a partially permeable membrane from low solute concentration to high solute concentration
- Both processes continue until dynamic equilibrium is reached
Dynamic Equilibrium
- The number of particles moving into the cell is equal to the number of particles moving out of the cell
Simple Diffusion versus Facilitated Diffusion
- Simple Diffusion: particles cross directly through the membrane; particles are small and uncharged
- Facilitated Diffusion: particles travel through special transport proteins; particles match the shape and charge requirement to fit through the channels
Active Transport: Protein Pumps
- Cells require substance movement against its concentration gradient from low to high concentration
- Protein pumps in cell membranes can achieve this for specific molecules
- This process requires energy
Bulk Transport
- Large particles moved into or out of the cell using vesicles (membrane-bound capsules)
- Types:
- Exocytosis: material moved out of the cell
- Endocytosis: material moved into the cell
- Pinocytosis: bulk transport of fluids and small particles into the cell ("cell drinking")
- Phagocytosis: bulk transport of solids into the cell ("cell eating")
Biologically Important Molecules
- Carbohydrates: in rice, potatoes, pasta, and bread (sugars and starches); important for short-term energy storage; also known as saccharides
- Lipids: in oil from plants and animal fats; important for long-term energy storage, thermoregulation, cell membranes, and cushioning
- Proteins: in meat and legumes; molecules that perform life functions (e.g. enzymes) and make up structure (e.g. muscles); also known as polypeptides
- Nucleic Acids: genetic material; instructions for life functions of cells and organisms; also known as DNA/RNA
Monomers and Polymers
- Monomers: individual units of polymers
- Polymers: many monomers linked together
- Carbohydrates:
- Monomers: monosaccharides (e.g. glucose)
- Polymers: polysaccharides (e.g. starch)
- Proteins:
- Monomers: amino acids
- Polymers: polypeptides
- Carbohydrates:
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Description
Understand the concepts of isotonic, hypertonic, and hypotonic solutions, as well as the selective permeability of cell membranes and how substances pass through them.