Questions and Answers
What is simple diffusion?
The movement of molecules from areas of higher concentration to areas of lower concentration.
What factors affect the rate of diffusion?
When is equilibrium reached when sugar is mixed with water?
When the dissolved sugar molecules are evenly distributed throughout the solution.
The molecules in a solid lump of sugar do not move.
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Diffusion is one of the processes whereby materials are exchanged between a cell and its environment.
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Facilitated diffusion requires energy and can transport molecules against a concentration gradient.
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Water diffuses down its concentration gradient by __________.
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Water always moves from ________ to ________ water concentration until equilibrium is reached.
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The movement of water can alter the volume or pressure of a cell, which is referred to as _________.
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A cell that is immersed in a hypertonic solution loses water and shrinks, a process called ________.
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A cell that is immersed in a hypotonic solution takes in water and swells. If the concentration difference is large enough, the movement of water into the cell can cause the cell to rupture, a process called _______.
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On average, the body is composed of about 60% water found both within the cells (______cellular fluid) and outside the cells (_______cellular fluid).
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What does extracellular fluid include?
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What is osmolarity?
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The directional movement of water occurs from a solution of ____________ osmolarity to a solution of ____________ osmolarity.
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An increase in water intake causes a(n) ___________________ in the plasma osmolarity.
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An IV solution of 0.45% NaCl is ________________ and induces the movement of water ________________.
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If the osmotic concentration of two solutions is equal, the solutions are _________. However, if the solutions have unequal osmotic concentrations, the solution with the higher concentration of solutes is ________ and the solution with the lower concentration is ________.
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Which molecule listed is most likely to cause osmosis in the body?
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What type of solution contains higher than normal amounts of osmotically active solutes?
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What happens to red blood cells put in a hypertonic solution?
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What type of transport does LDL (low-density lipoprotein) use to enter a cell?
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The sodium-potassium pump moves sodium out of the cell three ions at a time and returns potassium ions into the cell two ions at a time.
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What is the name of the protein carrier involved in counter-transport?
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Study Notes
Diffusion & Osmosis Key Concepts
- Simple Diffusion: Movement of molecules from high to low concentration (e.g., sugar dissolving in water).
- Factors Influencing Rate of Diffusion: Affected by temperature, molecular size, and steepness of concentration gradient.
- Equilibrium: Achieved when dissolved molecules, like sugar, are uniformly distributed in a solution.
True or False Statements
- Molecular Movement: Molecules in solid sugar do move (False statement).
- Diffusion Role: Diffusion is crucial for material exchange between cells and their environment (True statement).
- Facilitated Diffusion: Does not require energy and moves molecules down their concentration gradient (False).
Water Movement
- Osmosis: Water diffuses down its concentration gradient through this passive transport process.
- Water Concentration: Moves from higher to lower concentrations until equilibrium is achieved.
- Tonicity: Refers to how water movement can impact the volume and pressure of cells.
Solutions and Cellular Responses
- Hypertonic Solution: Causes cells to lose water and shrink (crenation).
- Hypotonic Solution: Leads cells to absorb water and can cause them to swell or rupture (lysis).
- Water Composition in Body: Approximately 60% of body weight; includes intracellular (intra) and extracellular (extra) fluid.
Osmolarity and Solutions
- Osmolarity: Refers to the concentration of solute in a solution.
- Water Movement Direction: Water moves from areas of lesser osmolarity to greater osmolarity.
- Physiological Changes: Increased water intake decreases plasma osmolarity.
IV Solutions and Responses
- 0.45% NaCl IV Solution: Hypotonic, promoting water movement into cells.
- Osmotic Concentration: Isotonic solutions have equal osmotic concentrations; hypertonic has a higher concentration, hypotonic has lower.
Cellular Effects and Transport Mechanisms
- Red Blood Cells in Hypertonic Solution: Results in crenation (shriveling).
- Low-Density Lipoprotein (LDL) Transport: Enters cells via receptor-mediated endocytosis.
- Sodium-Potassium Pump: Transports three sodium ions out and two potassium ions into cells; confirmed as true.
Additional Transport Information
- Counter-Transport Protein: Involves antiport mechanisms.
Important Notes
- Protein Role in Osmosis: Proteins in the body are significant contributors to osmotic pressure.
- Higher Osmotic Solutions: Lead to water movement towards the area with higher solute concentration.
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Description
Test your knowledge on diffusion and osmosis with these flashcards. Learn how molecules move from high to low concentration and understand the factors that affect the rate of diffusion. Perfect for reviewing key concepts in biology.
