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What is the primary function of the Golgi apparatus?
Which face of the Golgi apparatus is responsible for receiving products from the endoplasmic reticulum (ER)?
What is the primary function of mitochondria within the cell?
Chloroplasts are primarily involved in which process?
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Which component of the cytoskeleton is the thickest filament?
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What defines an amphipathic molecule?
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What structure do phospholipids contain that contributes to their unique properties?
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Which type of hydrocarbon tail in lipids remains fluid and prevents packing?
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What is the primary function of the nucleus in a cell?
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Which parameter of microscopy measures the clarity of an image?
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What distinguishes a scanning electron microscope (SEM) from a transmission electron microscope (TEM)?
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Which type of endoplasmic reticulum is involved in lipid synthesis and detoxification?
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Which statement about ribosomes is true?
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In light microscopy, what is magnification?
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What type of sample preparation is typically necessary for transmission electron microscopy (TEM)?
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What role does the nucleolus play in the cell?
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Which system is unable to exchange energy or matter with its surroundings?
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What is the primary concept of the first law of thermodynamics?
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Which example best represents an increase in entropy?
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What type of process leads to an increase in entropy by itself?
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What characterizes a system with higher stability in terms of free energy?
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Which type of chemical reaction is characterized by absorbing energy and being non-spontaneous?
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Which component of ATP is primarily responsible for energy release?
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Which example illustrates a non-spontaneous process?
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What is the effect of cholesterol on membrane fluidity at higher temperatures?
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Which type of molecules easily diffuse across the cellular membrane?
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Which of the following molecules is impermeable to the cellular membrane?
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Which type of transport across the membrane does not require energy?
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What defines the term 'tonicity' in relation to cellular environments?
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Which metabolic pathway involves the consumption of energy to build complex molecules?
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Which type of energy is associated with the random movement of atoms or molecules?
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Which of the following is NOT a characteristic of potential energy?
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Study Notes
Light Microscopy
- Passes visible light through a specimen
- Light travels through lenses to create a magnified image
- Enables viewing of details too small for the naked eye
Microscopy Parameters
- Magnification: Ratio of image size to real size; light microscopes can magnify up to 1,000x.
- Resolution: Clarity of the image; ability to distinguish between two separate points.
- Contrast: Difference in brightness between light and dark areas; achieved through staining or labeling cell components.
Electron Microscopy
- Uses a beam of electrons to create images
- Electrons have a shorter wavelength than visible light, resulting in higher resolution (~nm)
- Resolution is 100x higher than standard light microscopy
Types of Electron Microscopes
- Scanning Electron Microscope (SEM): Scans the surface of a sample, producing detailed images.
- Transmission Electron Microscope (TEM): Electrons pass through a thin specimen, creating a projection image.
Nucleus
- Stores and protects the cell's genetic material (DNA)
Nucleolus
- Produces and assembles ribosomes
Ribosomes
- Responsible for protein synthesis
Endoplasmic Reticulum (ER)
- Smooth ER: No ribosomes; involved in diverse metabolic processes, lipid synthesis, carbohydrate metabolism, detoxification, and calcium storage.
- Rough ER: Contains ribosomes; responsible for protein synthesis and secretion, including glycoproteins, and membrane protein formation.
Golgi Apparatus
- Functions as the cell's "shipping and receiving center".
- Cis face: Receives products from the ER.
- Trans face: Ships products from the Golgi.
- Transport vesicles: Transport products between the ER and Golgi, and from the Golgi to other structures.
Mitochondria
- The "powerhouse of the cell".
- Consumes chemical energy and uses oxygen to generate ATP from glucose, fats, and other fuel sources.
Chloroplasts
- Site of photosynthesis in plants and algae.
- Convert solar energy into chemical energy, synthesizing sugars from carbon dioxide and water.
Cytoskeleton
- Network of fibers extending throughout the cell's cytoplasm.
- Microtubules (tubulin): The thickest filaments; involved in cell shape, movement, and organelle transport.
- Microfilaments (actin): The thinnest filaments; involved in muscle contraction and cell division.
- Intermediate filaments: Medium-sized filaments; provide structural support and anchor organelles.
Cell Walls
- Found in plant, bacterial, and fungal cells.
- Provide structural support and protection.
Amphipathic Molecules
- Possess both hydrophilic (water-loving) and hydrophobic (water-fearing) regions.
- Hydrophilic head groups interact with water.
- Hydrophobic tails avoid water.
Phospholipids
- Structural components of cell membranes.
- Consist of a glycerol backbone, two fatty acid tails (hydrophobic), and a phosphate group with a polar head group (hydrophilic).
Lipids and Cellular Membranes
- Unsaturated hydrocarbon tails: Maintain fluidity; kinks in the tails prevent close packing.
- Saturated hydrocarbon tails: Become viscous; tails pack tightly together.
- Cholesterol: Wedges between lipids; reduces fluidity at high temperatures, increases fluidity at low temperatures.
Membrane Transport
- Passive transport: Requires no energy input. Examples include diffusion, osmosis, and facilitated diffusion.
- Active transport: Requires energy input to move molecules against their concentration gradient.
Tonicity
- The ability of a solution to change the volume of cells by altering their water content.
Metabolic Pathways
- Catabolism: Breaks down complex molecules into simpler compounds; releases energy. Example: Breakdown of glucose in the presence of oxygen, producing carbon dioxide and water, releasing stored energy for cellular work.
- Anabolism: Builds complex molecules from simpler ones; requires energy. Example: Protein synthesis.
Cellular Energy
- Kinetic energy: Energy of motion, like muscle contraction.
- Thermal energy: Kinetic energy associated with the random movement of atoms or molecules, such as heat transfer.
- Potential energy: Stored energy based on position, structure, or properties; examples include batteries, dynamite, and a drawn bow.
- Chemical energy: Stored energy released during chemical reactions; examples include burning wood, gasoline in cars, and eating food.
Thermodynamic Systems
- Isolated system: No exchange of energy or matter with surroundings, like a liquid in a thermos.
- Open system: Exchange of energy and matter with surroundings, like a pot of boiling water on a stovetop.
Laws of Thermodynamics
- First Law: Energy can be transferred or transformed; it cannot be created or destroyed. Example: A plant converts sunlight into chemical energy.
- Second Law: Every energy transfer or transformation increases the entropy of the universe; entropy is a measure of disorder or randomness in a system, like ice melting into a more disordered liquid.
Energetic Processes
- Spontaneous process (negative ΔG): Increases entropy and happens naturally, like water flowing downhill.
- Nonspontaneous process (positive ΔG): Decreases entropy and requires energy input, like a machine pumping water uphill.
Free Energy
- A measure of a system's stability; lower free energy indicates a more stable system.
Chemical Reactions
- Exergonic (negative ΔG): Releases energy spontaneously, like a downhill process.
- Endergonic (positive ΔG): Requires energy input, like an uphill process.
ATP
- Adenosine triphosphate, a molecule that stores and releases chemical energy.
- Composed of ribose sugar, adenine nitrogenous base, and a triphosphate group.
- The bond between the second and third phosphate groups stores energy that can be released during hydrolysis, forming ADP.
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Description
Explore the fundamental concepts of light and electron microscopy in this quiz. Learn about magnification, resolution, and contrast, as well as the distinct types of electron microscopes available. Perfect for students seeking to enhance their understanding of microscopy techniques and applications.
