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Questions and Answers
What is the main function of the cell membrane in regulating what enters and leaves the cell?
What is the main function of the cell membrane in regulating what enters and leaves the cell?
What type of transport requires energy and involves the movement of molecules against their concentration gradient?
What type of transport requires energy and involves the movement of molecules against their concentration gradient?
What is the term used to describe the dynamic structure of the cell membrane, with proteins and lipids moving freely?
What is the term used to describe the dynamic structure of the cell membrane, with proteins and lipids moving freely?
What is the type of transport that involves the movement of molecules through transport proteins, but does not require energy?
What is the type of transport that involves the movement of molecules through transport proteins, but does not require energy?
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What is the primary function of the cell membrane in terms of cell shape?
What is the primary function of the cell membrane in terms of cell shape?
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What happens to a cell when it is placed in an isotonic solution?
What happens to a cell when it is placed in an isotonic solution?
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What is an example of an isotonic solution?
What is an example of an isotonic solution?
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What is the direction of diffusion in a concentration gradient?
What is the direction of diffusion in a concentration gradient?
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What is the effect of a steeper concentration gradient on the rate of diffusion?
What is the effect of a steeper concentration gradient on the rate of diffusion?
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What is the term for a gradual change in the concentration of a substance from one area to another?
What is the term for a gradual change in the concentration of a substance from one area to another?
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What type of concentration gradient has a decreasing concentration of a substance from one area to another?
What type of concentration gradient has a decreasing concentration of a substance from one area to another?
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Why are concentration gradients important in biological systems?
Why are concentration gradients important in biological systems?
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Study Notes
Cell Membrane
- Structure: Phospholipid bilayer with embedded proteins
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Functions:
- Regulates what enters and leaves the cell
- Maintains cell shape
- Provides mechanical support
- Acts as a barrier to separate internal and external environments
- Semipermeability: Allows certain substances to pass through while restricting others
- Fluid mosaic model: Describes the dynamic structure of the cell membrane, with proteins and lipids moving freely
Cellular Transport
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Types:
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Passive transport: No energy required
- Diffusion: Movement of molecules from high to low concentration
- Osmosis: Movement of water molecules from high to low concentration
- Facilitated diffusion: Assisted transport of molecules through transport proteins
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Active transport: Energy required
- Carrier proteins: Transport molecules against their concentration gradient
- Pump proteins: Use energy to transport molecules against their concentration gradient
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Passive transport: No energy required
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Transport mechanisms:
- Simple diffusion: Direct movement of molecules through the membrane
- Facilitated diffusion: Transport proteins assist molecule movement
- Vesicle transport: Molecules transported through vesicles
Cell Organelles
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Types:
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Membrane-bound organelles:
- Nucleus: Contains genetic material
- Mitochondria: Generates energy through cellular respiration
- Endoplasmic reticulum (ER): Involved in protein synthesis and transport
- Golgi apparatus: Modifies and packages proteins for transport
- Lysosomes: Contains digestive enzymes for breaking down waste
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Non-membrane-bound organelles:
- Ribosomes: Site of protein synthesis
- Cytoskeleton: Provides structural support and shape
- Centrioles: Involved in cell division and formation of cilia
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Membrane-bound organelles:
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Functions:
- Protein synthesis and transport
- Energy generation and storage
- Waste management and recycling
- Cell signaling and communication
- **Cell division and growth
Cell Membrane
- Consists of a phospholipid bilayer with embedded proteins
- Regulates the movement of substances in and out of the cell
- Maintains cell shape and provides mechanical support
- Acts as a barrier to separate internal and external environments
- Is semipermeable, allowing certain substances to pass through while restricting others
- Has a dynamic structure, with proteins and lipids moving freely, described by the fluid mosaic model
Cellular Transport
- There are two main types of transport: passive and active
- Passive transport does not require energy
- Diffusion is the movement of molecules from high to low concentration
- Osmosis is the movement of water molecules from high to low concentration
- Facilitated diffusion is the assisted transport of molecules through transport proteins
- Active transport requires energy
- Carrier proteins transport molecules against their concentration gradient
- Pump proteins use energy to transport molecules against their concentration gradient
- Transport mechanisms include simple diffusion, facilitated diffusion, and vesicle transport
Cell Organelles
- There are two main types of organelles: membrane-bound and non-membrane-bound
- Membrane-bound organelles include:
- Nucleus, which contains genetic material
- Mitochondria, which generates energy through cellular respiration
- Endoplasmic reticulum (ER), which is involved in protein synthesis and transport
- Golgi apparatus, which modifies and packages proteins for transport
- Lysosomes, which contain digestive enzymes for breaking down waste
- Non-membrane-bound organelles include:
- Ribosomes, which are the site of protein synthesis
- Cytoskeleton, which provides structural support and shape
- Centrioles, which are involved in cell division and formation of cilia
- Organelles perform various functions, including:
- Protein synthesis and transport
- Energy generation and storage
- Waste management and recycling
- Cell signaling and communication
- Cell division and growth
Osmosis and Diffusion
- An isotonic solution has the same concentration of solutes as another solution, such as a cell or a reference solution.
- In an isotonic solution, there is no net movement of water into or out of the cell, maintaining its shape and size.
- Examples of isotonic solutions include 0.9% saline solution (used in medical settings) and a 5% glucose solution.
Concentration Gradients
- A concentration gradient is a gradual change in the concentration of a substance from one area to another.
- There are two types of concentration gradients: concentration gradient (decreasing concentration) and reverse concentration gradient (increasing concentration).
- Diffusion occurs from an area of higher concentration to an area of lower concentration, down the concentration gradient.
- The steeper the concentration gradient, the faster the rate of diffusion.
- Concentration gradients are important in biological systems, driving the movement of molecules and ions across cell membranes.
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Description
Test your knowledge of the cell membrane's structure, functions, and properties, including its phospholipid bilayer, embedded proteins, and semipermeability.
