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Questions and Answers
What is the primary component of the cell membrane that forms the phospholipid bilayer?
What is the primary component of the cell membrane that forms the phospholipid bilayer?
What characteristic do phosphate heads of phospholipids possess?
What characteristic do phosphate heads of phospholipids possess?
In diffusion, molecules move from an area of ______ concentration to an area of ______ concentration.
In diffusion, molecules move from an area of ______ concentration to an area of ______ concentration.
What does a hypertonic solution do to a cell placed in it?
What does a hypertonic solution do to a cell placed in it?
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What is the outcome for a cell when placed in a hypotonic solution?
What is the outcome for a cell when placed in a hypotonic solution?
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What best describes the term 'Isotonic solution'?
What best describes the term 'Isotonic solution'?
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Which statement about facilitated diffusion is correct?
Which statement about facilitated diffusion is correct?
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What characteristic defines the 'Fluid Mosaic Model' of the cell membrane?
What characteristic defines the 'Fluid Mosaic Model' of the cell membrane?
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What does the term 'semipermeable' refer to in the context of the cell membrane?
What does the term 'semipermeable' refer to in the context of the cell membrane?
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Which of the following correctly describes osmosis?
Which of the following correctly describes osmosis?
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What distinguishes the hydrophobic lipid tails from the hydrophilic phosphate heads of phospholipids in the cell membrane?
What distinguishes the hydrophobic lipid tails from the hydrophilic phosphate heads of phospholipids in the cell membrane?
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In what way does a hypertonic solution affect the movement of water in a cell?
In what way does a hypertonic solution affect the movement of water in a cell?
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Which of the following best describes the concept of facilitated diffusion?
Which of the following best describes the concept of facilitated diffusion?
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What does it mean for a cell membrane to be described as 'semipermeable'?
What does it mean for a cell membrane to be described as 'semipermeable'?
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In which solution is a cell likely to burst due to water influx?
In which solution is a cell likely to burst due to water influx?
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What occurs to a cell when it is placed in an isotonic solution?
What occurs to a cell when it is placed in an isotonic solution?
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How does osmosis differ from diffusion?
How does osmosis differ from diffusion?
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What is a key characteristic of the Fluid Mosaic Model of the cell membrane?
What is a key characteristic of the Fluid Mosaic Model of the cell membrane?
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Which term best describes the condition of a cell in a hypertonic solution?
Which term best describes the condition of a cell in a hypertonic solution?
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What is the primary factor influencing the direction of water movement during osmosis?
What is the primary factor influencing the direction of water movement during osmosis?
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Study Notes
Cell Membrane Structure
- Cell membranes are composed of lipids and proteins, separating the cell contents from the outside world.
- The bilayer structure is formed by two layers of phospholipids.
- Phospholipid heads are hydrophilic (water-loving).
- Phospholipid tails are hydrophobic (water-fearing).
- Heads orient towards the water, tails away from water.
Fluid Mosaic Model
- A more accurate model of the cell membrane structure.
- Called "fluid" because the components are not static but can move.
- Called "mosaic" because of the various components embedded in the membrane, such as proteins, cholesterol, and glycoproteins.
- Includes glycoproteins and glycolipids on the cell surface.
Membrane Permeability
- Cell membranes are semipermeable, allowing some substances to pass through but not others.
Movement Across Membranes
- Diffusion: Movement of liquid or gas molecules from high concentration to low concentration.
- Osmosis: Diffusion of water across a semipermeable membrane.
- Hypertonic Solution: A solution with a higher solute concentration outside the cell than inside. Water moves out of the cell, causing it to shrink (plasmolyze).
- Hypotonic Solution: A solution with a lower solute concentration outside the cell than inside. Water moves into the cell, causing it to swell or burst (lyse).
- Isotonic Solution: A solution with equal solute concentration inside and outside the cell. Water movement is balanced.
Facilitated Diffusion
- Passive transport using carrier proteins to move molecules across the membrane.
- Does not require energy.
- Carrier proteins change shape to move molecules.
Active Transport
- Requires energy (ATP).
- Moves molecules against the concentration gradient (low to high).
- The Sodium-Potassium (Na+/K+) pump is an example.
Bulk Transport
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Endocytosis: Taking large molecules into the cell.
- Vesicles engulf the substance.
- Exocytosis: Removing large molecules from the cell by fusing vesicles with the membrane.
- Bulk transport is an important aspect of transporting materials in and out of the cell.
Receptor-Mediated Endocytosis
- Process that uses specific receptors on the cell surface to take in target molecules, a highly targeted process, which specifically imports substances into cells.
- Specific to the substance being transported.
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Description
Explore the intricate details of cell membrane structure, including the fluid mosaic model and membrane permeability. Learn about the dynamics of movement across membranes, covering key processes such as diffusion and osmosis.
