Questions and Answers
What is the nuclear membrane/envelope?
What is a nucleolus?
What is the nucleus?
What is the function of the cell wall?
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Why doesn't onion have chloroplasts?
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What did iodine do to the onion cells?
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What is in the center of each cell?
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What is/are visible inside the nucleus?
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What surrounds each cell?
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What is found just inside the cell wall?
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What are the colored structures found in the Elodea?
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How many chloroplasts are typically in a cell?
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When focused up and down on layers of Elodea, what was detected?
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Which cells of Elodea are bigger?
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What is cyclosis?
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What does the vacuole hold?
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What is the shape of eggplant cells?
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What is the name of the pigment in eggplant cells?
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What structure is the pigment found in?
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What are the channels in the thick layer surrounding the cell and their function?
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What structure is found in the 'notch' in the colored area?
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What is the shape of potato pulp cells?
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What are the oval-ish structures in each cell?
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What do amyloplasts contain?
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When iodine is dropped on the pulp cells, what happens?
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What cell part do stone cells mostly consist of?
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What substance makes up this specific cell structure in stone cells?
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What are the channels through the cell wall in stone cells?
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Are stone cells living or dead? Why?
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What purpose do stone cells have?
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What is the nuclear envelope structure/function?
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What is a nucleolus?
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What is the stroma?
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Study Notes
Cell Structures in Onion Cells
- Nuclear membrane/envelope: Composed of phospholipid bilayers with pores that facilitate transport.
- Nucleus: Contains the nucleolus and is central to genetic material.
- Nucleolus: A condensed region responsible for ribosomal RNA (rRNA) synthesis.
Unique Features of Onion and Other Cells
- Onion cells lack chloroplasts: Grown underground, thus do not perform photosynthesis.
- Reaction to iodine: Stains onion cells yellowish, enhancing visibility of organelles.
- Vacuole: Occupies the center of each cell, storing substances and maintaining turgor pressure.
Organelles and Their Functions
- Inside the nucleus: Nucleoli are visible; crucial for ribosome assembly.
- Cell wall: Surrounds each cell, providing structural support.
- Plasma membrane: Found just within the cell wall, regulates what enters and exits the cell.
Elodea Cell Characteristics
- Chloroplasts: Present in Elodea, containing chlorophyll, about 30-50 per cell.
- Layer observation: Two layers of cells detected; top layer receives more sunlight, showing more chloroplasts.
- Cell sizes: Larger cells found in the upper layer, smaller in the lower layer.
Cytoplasm and Vacuoles
- Cyclosis: Describes the movement of cytoplasm within the cell.
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Vacuole functions:
- Stores organic compounds and pigments.
- Provides protection by storing poisons.
- Maintains turgor pressure to keep plants upright.
Eggplant Cell Structures
- Shape of eggplant cells: Spherically shaped, accommodating storage.
- Pigment presence: Anthocyanin, a water-soluble pigment found in vacuoles, gives color.
- Amyloplasts in potato cells: Oval structures responsible for starch storage (amylose and amylopectin).
Chemical Reactions and Cell Types
- Iodine interaction: Turns starch in amyloplasts purple, indicating presence of carbohydrates.
- Stone cells: Composed largely of cell walls made of lignin, providing structural support and are dead at maturity.
- Plasmodesmata: Channels in cell walls allowing nutrient and waste transport, facilitating cell communication.
Summary of Cell Functions
- Purpose of stone cells: Provide structure and support, contributing to the crunchiness of fruits like pears.
- Nuclear envelope: Functions to protect the nucleus while controlling substance passage.
- Stroma: The fluid within chloroplasts where photosynthesis reactions take place.
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Description
Test your knowledge on the structure of onion cells with this labeling quiz. Identify key components like the nuclear membrane, nucleolus, and nucleus, and understand why onions do not have chloroplasts. Perfect for biology students looking to reinforce their learning!
