Biology Flashcards: Cell Structures & Processes
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Questions and Answers

Which of the following do mitochondria and chloroplasts have in common?

  • Both produce ATP
  • Both contain DNA
  • Both are found only in animal cells
  • Both have a double membrane structure (correct)
  • Which of the following processes includes all others: osmosis, diffusion of a solute across a membrane, facilitated diffusion, and transport of an ion down its electrochemical gradient?

  • Active transport
  • Facilitated diffusion
  • Passive transport (correct)
  • Osmosis
  • Which of the following are functions of the cytoskeleton?

  • Support
  • Motility
  • Cell division
  • All of the above (correct)
  • Which of the following is incorrect about the extracellular matrix?

    <p>It is exclusively found in animal cells</p> Signup and view all the answers

    Which of the following is correct about the extracellular matrix?

    <p>All of the above</p> Signup and view all the answers

    Which one of the following molecules is most likely to diffuse freely across the lipid bilayer of the plasma membrane without the involvement of a transport protein?

    <p>Carbon dioxide</p> Signup and view all the answers

    Which of the following would be least likely to diffuse through a plasma membrane without the help of a transport protein?

    <p>A polar molecule</p> Signup and view all the answers

    Passive transport permits the transported molecules to move in either direction, but the majority of transport occurs down the concentration gradient of the molecule.

    <p>True</p> Signup and view all the answers

    Diffusion is an active process.

    <p>False</p> Signup and view all the answers

    Which one of the following is not in some way involved in facilitated diffusion?

    <p>An outside energy source</p> Signup and view all the answers

    Imagine two solutions separated by a selectively permeable membrane that allows water to pass, but not sucrose or glucose. The membrane separates a 0.2 molar sucrose solution from a 0.2 molar glucose solution. With time, how will the solution change?

    <p>After sucrose dissociates into two monosaccharides, water will be osmotically drawn to that side of the membrane.</p> Signup and view all the answers

    What is cotransport?

    <p>Cotransport is active transport driven by a concentration gradient.</p> Signup and view all the answers

    What is the voltage across a cell membrane called?

    <p>Membrane potential.</p> Signup and view all the answers

    One of the functions of cholesterol in animal cell membranes is to?

    <p>Maintain membrane fluidity.</p> Signup and view all the answers

    Which of the following is a difference between active transport and facilitated diffusion?

    <p>Active transport requires energy from ATP, and facilitated diffusion does not</p> Signup and view all the answers

    Which one of the following pairs matches the name of a membrane transport process with the primary function of that process?

    <p>Pinocytosis - the uptake of water and small solutes into the cell by formation of vesicles at the plasma membrane.</p> Signup and view all the answers

    Which of the following correctly states the relationship between anabolic and catabolic pathways?

    <p>Anabolic pathways synthesize more complex organic molecules using the energy derived from catabolic pathways</p> Signup and view all the answers

    According to the second law of thermodynamics, the decrease in entropy associated with life must be compensated for by an increase in entropy in the environment that life occurs in.

    <p>True</p> Signup and view all the answers

    Metabolic pathways in cells are typically far from equilibrium. Which of the following processes tend to keep these pathways away from equilibrium?

    <p>Both A and B</p> Signup and view all the answers

    What is ATP?

    <p>The energy currency of the cell that powers most cellular work</p> Signup and view all the answers

    A chemical reaction is designated as exergonic rather than endergonic when?

    <p>The products are less complex than the reactants.</p> Signup and view all the answers

    Enzymes speed up the rate of the reaction without changing the delta-G for the reaction.

    <p>True</p> Signup and view all the answers

    Enzymes generally slow reaction rates.

    <p>False</p> Signup and view all the answers

    Which of the following statements about the active site of an enzyme is correct?

    <p>The active site may resemble a groove or pocket in the surface of a protein into which the substrate fits.</p> Signup and view all the answers

    The process of stabilizing the structure of an enzyme in its active form by the binding of a molecule is an example of?

    <p>Allosteric regulation.</p> Signup and view all the answers

    Study Notes

    Cell Organelles and Structures

    • Mitochondria and chloroplasts share a double membrane structure, essential for their functions in energy production and photosynthesis.
    • The extracellular matrix contains proteins and carbohydrates, plays a role in mechanical signaling, and attaches to the plasma membrane; however, it is not present in plant cells.
    • Cytoskeleton provides structural support and aids in cellular motility, important for cell shape and movement.

    Transport Mechanisms

    • Passive transport encompasses diffusion, osmosis, and facilitated diffusion, allowing molecules to move without energy input, generally down their concentration gradients.
    • Facilitated diffusion assists molecules, such as ions and larger solutes, via transport proteins and does not require external energy.
    • Active transport requires energy, typically from ATP, to move substances against their concentration gradients.
    • An example of passive diffusion is carbon dioxide, which can cross the plasma membrane freely due to its nonpolar nature, while polar molecules struggle without assistance.
    • Membrane potential is the voltage across a cell membrane, influencing transport and communication.

    Solutions and Osmosis

    • In a selectively permeable membrane scenario, where sucrose and glucose solutions are separated, water will move toward the side with greater solute concentration after sucrose dissociates, altering the solution's balance.

    Metabolism and Energy

    • Anabolic pathways build complex organic molecules and rely on the energy produced from catabolic pathways, which break down these molecules.
    • The second law of thermodynamics states that the entropy decrease in living systems must be compensated by increased entropy elsewhere.
    • Metabolic pathways maintain non-equilibrium through the continuous removal of products and the intake of free energy from sources like food.

    Enzymes and Reactions

    • Enzymes function by speeding up reactions without altering the overall energy change (delta-G) of the process.
    • The active site of an enzyme is a specific region where substrates bind, often resembling a groove or pocket configuration.
    • Enzymes exhibit allosteric regulation, wherein molecule binding stabilizes their active form, enhancing catalytic activity.
    • A reaction is characterized as exergonic if the products formed are less complex than the initial reactants.

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    Test your knowledge on key concepts in biology with these flashcards focused on cell structures and processes. Explore topics like mitochondria, chloroplasts, osmosis, and the cytoskeleton. Perfect for students looking to reinforce their understanding of cellular function.

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