Questions and Answers
What is the role of ribosomes in protein synthesis?
Where are free ribosomes located and what is their main function?
Which statement about the endoplasmic reticulum is correct?
What process describes the conversion of DNA to RNA and then to protein?
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Which type of ribosomes are involved in synthesizing proteins that are eventually secreted from the cell?
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What is the primary function of smooth endoplasmic reticulum?
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What is a primary function of smooth endoplasmic reticulum?
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Which statement about the Golgi complex is most accurate?
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What is the primary role of lysosomes in a cell?
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How do peroxisomes contribute to cellular metabolism?
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What type of vacuole is essential for maintaining water levels in certain cells?
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What is a significant function of the central vacuole in plant cells?
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What process allows lysosomes to recycle organic materials in a cell?
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What modification occurs to materials as they pass through the Golgi complex?
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What do all cells have in common?
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Which of the following statements is true about prokaryotic cells?
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What is the primary function of the nuclear pores?
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Which of these is NOT an endomembrane organelle?
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What allows compartmentalization to be effective in eukaryotic cells?
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Which unique cell component is found only in plant cells?
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Where is ribosomal RNA synthesized?
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What must occur for DNA to exit the nucleus?
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What is the primary site of the Krebs cycle within the mitochondria?
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Which of the following components is found inside the chloroplast?
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What role do microtubules play in the cytoskeleton?
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Which of the following statements about mitochondria is true?
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What is the function of the cytoskeleton in cells?
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What is located in the stroma of a chloroplast?
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Which type of fiber is responsible for cell motility in the cytoskeleton?
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What distinct feature do mitochondria possess that is not found in many other organelles?
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What is the primary function of albumin in the blood?
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What effect does hepatitis C have on liver cells?
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Where is insulin synthesized in normal pancreatic cells?
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What is a consequence of the immune system attacking pancreatic cells in type 1 diabetes?
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According to the endosymbiont theory, what role did prokaryotic cells play?
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What evidence supports the endosymbiont theory regarding mitochondria?
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What structural feature of mitochondria increases their surface area for cellular respiration?
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What is found in the intermembrane space of mitochondria?
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Study Notes
Cells
- Basic structural and functional units of organisms.
- All cells have a plasma membrane, cytosol, chromosomes, and ribosomes.
- Two main types of cells: prokaryotes and eukaryotes.
Prokaryotes vs Eukaryotes
- Prokaryotes: Include Bacteria and Archaea, DNA located in a nucleoid region, generally smaller than eukaryotes.
- Eukaryotes: Include protists, fungi, animals, and plants, DNA contained within a nucleus, possess membrane-bound organelles.
Organelles
- Membrane-bound structures found in eukaryotic cells.
- Classified into two groups: endomembrane organelles and energy organelles.
Endomembrane Organelles
- Nuclear envelope, endoplasmic reticulum, Golgi complex, lysosomes, vesicles/vacuoles, plasma membrane.
Energy Organelles
- Mitochondria and chloroplasts.
Compartmentalization
- Organelles allow for different metabolic reactions in distinct locations, increasing surface area, and preventing interference between reactions.
Unique Cell Components
- Plant unique components: chloroplasts, central vacuole, cell wall, plasmodesmata.
- Animal unique components: lysosomes, centrosomes, flagella.
Nucleus
- Houses chromosomes and enclosed by a double membrane nuclear envelope with pores that regulate material exchange.
- Contains a nucleolus for ribosomal RNA (rRNA) synthesis, which forms ribosome subunits.
Protein Synthesis Process
- DNA is transcribed into mRNA, modified, and transported out of the nucleus.
- Ribosomes, composed of rRNA and proteins, translate mRNA into polypeptides.
Ribosomes
- Located in cytosol ("free ribosomes") or bound to the endoplasmic reticulum ("bound ribosomes").
- Free ribosomes synthesize proteins for cytosolic functions, while bound ribosomes produce proteins for secretion or membrane incorporation.
Endoplasmic Reticulum (ER)
- Network of membranous sacs and tubes with two types:
- Rough ER: Contains ribosomes, synthesizes membranes, and compartments proteins.
- Smooth ER: Lacks ribosomes, synthesizes lipids, metabolizes carbohydrates, and detoxifies toxins.
Golgi Complex
- Composed of flattened membranous sacs called cisternae, with directional flow:
- Cis face receives vesicles from the ER.
- Trans face sends vesicles to cytosol or for secretion.
- Modifies, sorts, and packages materials, ensuring correct protein folding.
Lysosomes and Peroxisomes
- Lysosomes: Hydrolytic enzyme sacs that recycle cellular materials through autophagy.
- Peroxisomes: Membrane-bound compartments that break down hydrogen peroxide (H2O2) produced in metabolic reactions.
Vacuoles
- Large vesicles from ER and Golgi with selective transport capabilities.
- Types include:
- Food vacuole: Formed via phagocytosis, digested by lysosomes.
- Contractile vacuole: Maintains water levels in cells.
- Central vacuole (plants): Stores inorganic ions and water; crucial for turgor pressure.
Endosymbiont Theory
- Explains how mitochondria and chloroplasts resemble prokaryotes, suggesting they originated from engulfed prokaryotic cells.
- Evidence includes double membranes, ribosomes, circular DNA, and self-sufficient functioning.
Mitochondria
- Powerhouse of the cell, site of cellular respiration.
- Features include a smooth outer membrane and a folded inner membrane (cristae) that increases surface area.
- Internal compartments include intermembrane space and mitochondrial matrix, where the Krebs cycle occurs.
Chloroplast
- Found in photosynthetic organisms, site of photosynthesis containing chlorophyll.
- Inner membrane features thylakoids arranged in grana for light-dependent reactions; stroma surrounds thylakoids for the Calvin cycle.
Cytoskeleton
- Network of fibers providing structural and mechanical support in the cytoplasm; anchors organelles and facilitates vesicle movement.
- Composed of three types of fibers: microtubules, microfilaments, and intermediate filaments.
Microtubules
- Hollow, rod-like structures made from tubulin, formed from the centrosome.
- Provide structural support for organelle movement and assist in chromosome separation during cell division.
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Description
This quiz explores the essential components of cells, including the differences between prokaryotic and eukaryotic cells. You will also learn about various organelles and their functions in cellular processes. Test your knowledge on the structural and functional units of life!
