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Hypotonic, Isotonic, and Hypertonic Solutions (Lesson 2 Page 4)
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Hypotonic Solution: A solution that has a lower concentration of solutes compared to another solution. When a cell is placed in a hypotonic solution, water moves into the cell, causing it to swell and potentially burst (lyse).
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Isotonic Solution: A solution that has an equal concentration of solutes compared to another solution. When a cell is placed in an isotonic solution, there is no net movement of water in or out of the cell, meaning the cell maintains its normal shape.
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Hypertonic Solution: A solution that has a higher concentration of solutes compared to another solution. When a cell is placed in a hypertonic solution, water moves out of the cell, causing it to shrink (crenate).
Difference between Exocytosis and Endocytosis (Lesson 2 Page 5)
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Exocytosis: The process by which cells expel materials in vesicles that fuse with the plasma membrane. This is essential for the secretion of substances (like hormones and neurotransmitters) and for the removal of waste materials from the cell.
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Endocytosis: The process by which cells take in substances by engulfing them in vesicles. This can occur in different forms:
- Phagocytosis: "Cell eating," where large particles are brought into the cell.
- Pinocytosis: "Cell drinking," where liquids and small particles are taken up.
- Receptor-mediated endocytosis: A targeted process where cells internalize specific molecules based on receptor-ligand interactions.
Type of Solution Saltwater Fish Live In (Lesson 2 Page 4)
Saltwater fish live in a hypertonic solution compared to their body fluids. Their bodies have a lower concentration of salt than the surrounding saltwater, which causes water to flow out of the fish's body through osmosis. To cope with this, saltwater fish actively drink seawater and excrete excess salt through their gills and urine.
Main Functions of Organelles (Lesson 3 Page 2)
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Endoplasmic Reticulum (ER):
- Rough ER: Has ribosomes attached and is involved in protein synthesis and processing.
- Smooth ER: Lacks ribosomes and is involved in lipid synthesis, detoxification, and calcium ion storage.
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Nucleus: The control center of the cell that houses the cell's DNA; it regulates gene expression and cell division.
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Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.
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Central Vacuoles: Large vacuoles in plant cells that store nutrients, waste products, and help maintain turgor pressure.
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Ribosomes: The site of protein synthesis; they can be free-floating in the cytoplasm or attached to the rough ER.
Human Body Cell with the Highest Concentration of Mitochondria (Lesson 4 Page 2 and Practice Question #1 L4 Pg4)
The human body cell with the highest concentration of mitochondria is the muscle cell, particularly in cardiac muscle cells. This is because muscle cells require a significant amount of energy (ATP) to support their constant and vigorous activity, especially in the heart where continuous contraction is necessary for blood circulation. Mitochondria are the powerhouse of the cell, providing the energy required for muscle contractions.
This comprehensive overview should help you with your lesson materials. If you have any additional questions or need further clarification on any topic, feel free to ask!
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