Cell Biology: Cellular Structure and Function
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Questions and Answers

Which of the following is NOT an example of an anabolic reaction?

  • Protein synthesis
  • Breakdown of glucose through glycolysis (correct)
  • DNA replication
  • Formation of polysaccharides

    • What is the primary function of the nucleolus?

  • Regulating cell division
  • Synthesizing ribosomes (correct)
  • Producing proteins
  • Storing genetic information

    • Which functional group is known for its role in energy storage and cell signaling?

  • Methyl (-CH3)
  • Hydroxyl (-OH)
  • Phosphate (-PO4) (correct)
  • Carboxyl (-COOH)

    • What is the difference between oxidation and reduction in redox reactions?

    <p>Oxidation involves the loss of electrons, while reduction involves the gain of electrons. (B)</p> Signup and view all the answers

    Which functional group is responsible for the acidic properties of carboxyl groups?

    <p>The oxygen atom (A)</p> Signup and view all the answers

    Which of the following molecules is transported across the cell membrane through facilitated diffusion?

    <p>Glucose (C)</p> Signup and view all the answers

    Which type of metabolic reaction involves breaking down complex molecules into simpler ones?

    <p>Catabolic reactions (B)</p> Signup and view all the answers

    What is the role of the nucleolar organizers in ribosome synthesis?

    <p>They act as templates for the synthesis of ribosomal RNA. (A)</p> Signup and view all the answers

    Which of the following is NOT a characteristic of active transport?

    <p>Occurs without the need for energy (B)</p> Signup and view all the answers

    Hydrolysis reactions primarily involve the ______ of chemical bonds.

    <p>cleavage (A)</p> Signup and view all the answers

    Why is the cell membrane described as selectively permeable?

    <p>It regulates the passage of certain molecules based on their size, charge, and solubility (A)</p> Signup and view all the answers

    Which type of transport requires the use of membrane channels?

    <p>Facilitated diffusion (B)</p> Signup and view all the answers

    Which functional group is involved in the formation of proteins and nucleic acids?

    <p>Amide (CONH2) (C)</p> Signup and view all the answers

    What is the primary function of phosphorylation reactions?

    <p>Adding a phosphate group to a molecule (A)</p> Signup and view all the answers

    Which of these processes involves the engulfment of solid particles?

    <p>Phagocytosis (B)</p> Signup and view all the answers

    Which of the following describes the movement of water from an area of high water concentration to an area of low water concentration across a semipermeable membrane?

    <p>Osmosis (B)</p> Signup and view all the answers

    How is the electrical potential difference of a nerve cell maintained?

    <p>By the Na+/K+ pump (C)</p> Signup and view all the answers

    Which of the following molecules uses receptor-mediated endocytosis for transport into the cell?

    <p>Iron (D)</p> Signup and view all the answers

    What is the purpose of exocytosis?

    <p>To remove waste products from the cell (B)</p> Signup and view all the answers

    In which solution would a cell swell and potentially burst?

    <p>Hypotonic (C)</p> Signup and view all the answers

    Which of the following is NOT a function of protein carriers in the cell membrane?

    <p>Providing structural support to the membrane (C)</p> Signup and view all the answers

    What is the primary component of the cytoplasm?

    <p>Water (D)</p> Signup and view all the answers

    Which of these is an example of a polar molecule that cannot passively diffuse across the cell membrane?

    <p>Glucose (C)</p> Signup and view all the answers

    Which type of endocytosis is responsible for the uptake of cholesterol into cells?

    <p>Receptor-mediated endocytosis (A)</p> Signup and view all the answers

    What is the primary difference between facilitated diffusion and active transport?

    <p>Facilitated diffusion moves molecules down their concentration gradient, while active transport moves molecules against their concentration gradient. (A)</p> Signup and view all the answers

    What is the primary function of the plasma membrane?

    <p>To regulate the exchange of substances between the cell and its environment. (A)</p> Signup and view all the answers

    Which statement accurately describes prokaryotic cells?

    <p>They do not have a membrane-bound nucleus. (B)</p> Signup and view all the answers

    How do phospholipids arrange themselves in the plasma membrane?

    <p>In a bilayer with hydrophobic tails facing each other. (A)</p> Signup and view all the answers

    What is one of the roles of membrane proteins?

    <p>They aid in cell recognition and communication. (A)</p> Signup and view all the answers

    What happens to the cell membrane fluidity when cholesterol levels increase?

    <p>Fluidity increases, which allows for better movement of proteins. (B)</p> Signup and view all the answers

    In what way does facilitated transport differ from passive transport?

    <p>Facilitated transport involves membrane proteins, while passive transport does not. (B)</p> Signup and view all the answers

    What characteristic defines eukaryotic cells as opposed to prokaryotic cells?

    <p>Eukaryotic cells have a membrane-bound nucleus. (A)</p> Signup and view all the answers

    What is the term used for the contents of a cell?

    <p>Protoplasm. (D)</p> Signup and view all the answers

    Which of the following is NOT a primary function of the cytoskeleton?

    <p>Generating DNA (A)</p> Signup and view all the answers

    What is the primary function of the peroxisome?

    <p>Breakdown of hydrogen peroxide (D)</p> Signup and view all the answers

    Which of the following structures is directly involved in the synthesis of proteins?

    <p>Ribosomes (B)</p> Signup and view all the answers

    Which organelle is responsible for packaging and modifying materials for export from the cell?

    <p>Golgi complex (C)</p> Signup and view all the answers

    Which type of endoplasmic reticulum is involved in the synthesis of proteins destined for secretion?

    <p>Rough endoplasmic reticulum (B)</p> Signup and view all the answers

    Which of the following is a characteristic of the inner membrane of the mitochondria?

    <p>It is highly folded into cristae. (A)</p> Signup and view all the answers

    Which type of cytoskeletal filament is responsible for providing mechanical strength beneath the plasma membrane?

    <p>Actin filaments (C)</p> Signup and view all the answers

    What is the main role of the nuclear envelope?

    <p>To regulate the movement of molecules between the nucleus and cytoplasm (D)</p> Signup and view all the answers

    Which of the following is NOT a function of the Golgi complex?

    <p>Synthesis of proteins (B)</p> Signup and view all the answers

    What is the role of the nucleolus in the nucleus?

    <p>To synthesize ribosomal RNA (A)</p> Signup and view all the answers

    Which of the following is a characteristic of microtubules?

    <p>They are involved in the movement of chromosomes during cell division. (D)</p> Signup and view all the answers

    Which organelle's function involves the breakdown of excess fatty acids?

    <p>Peroxisomes (C)</p> Signup and view all the answers

    What is the primary difference between rough endoplasmic reticulum and smooth endoplasmic reticulum?

    <p>Rough ER has ribosomes attached to it, while smooth ER does not. (A)</p> Signup and view all the answers

    What process is responsible for moving organelles along microtubule tracks?

    <p>Motor proteins (C)</p> Signup and view all the answers

    Study Notes

    Cellular Basis of Life

    • Cells are the basic units of structure and function in living organisms, which can be unicellular (single cell) or multicellular (multiple cells).
    • Cells are categorized as prokaryotic (bacteria, no membrane-bound nucleus or organelles) or eukaryotic (all other organisms, with a membrane-bound nucleus and organelles).
    • This module focuses on animal cells.

    The Cell: Parts and Functions

    • Cells are small, microscopic entities enclosed by a cell membrane.
    • Protoplasm is the internal contents of a cell.
    • Plasma membrane acts as a barrier and gateway, regulating substance exchange with the external environment.
    • It also enables cell communication.
    • The membrane's structure is a phospholipid bilayer with hydrophobic tails facing inward and hydrophilic heads outward.
    • Membrane proteins facilitate transport, cell recognition, and communication.
    • Cholesterol maintains membrane fluidity.

    Transport System in Cell Membrane

    • Cell membranes are selectively permeable.
    • Passive transport:
      • Diffusion: Movement of molecules from high to low concentration until equilibrium. Examples include oxygen and carbon dioxide.
      • Osmosis: Movement of water across a semipermeable membrane from a low solute concentration to a high one. Hypotonic solutions have lower solute concentration than the cell, causing water influx. Hypertonic solutions have higher solute concentration than the cell, causing water outflow. Isotonic solutions have equal solute concentration, resulting in no net water movement.
    • Active transport: Uses energy (ATP) to move substances against their concentration gradient, concentrating molecules within the cell.
    • Facilitated diffusion: Movement of molecules through protein channels or carriers with no energy expenditure.
    • Membrane transport mechanisms include endocytosis (taking in large molecules) and exocytosis (releasing large molecules). Types of endocytosis include phagocytosis (taking in solids), pinocytosis (taking in fluids), and receptor-mediated endocytosis (specific molecule uptake).

    Protoplasm: Cytoplasm

    • Cytoplasm: The cell's internal contents excluding the nucleus. Contains water, enzymes, and nutrients.
    • Cellular Structures and Organelles:
      • Ribosomes: Protein synthesis. Free in cytoplasm or bound to rough ER.
      • Endoplasmic Reticulum (ER): Network of membranes. Smooth ER lacks ribosomes, rough ER has ribosomes.
      • Golgi Complex: Modifies, stores, and packages proteins and lipids for secretion.
      • Lysosomes: Contain digestive enzymes to break down cellular waste and debris.
      • Peroxisomes: Breakdown fatty acids and hydrogen peroxide, and participate in other metabolic processes.
      • Mitochondria: Cellular respiration, produce ATP. Have an inner membrane folded into cristae and an outer membrane. Have their own DNA.
      • Cytoskeleton: Provides structural support, intracellular transport, movement. Composed of actin filaments, intermediate filaments, and microtubules.

    Nucleus

    • Encloses the cell's genetic material (DNA).
    • Nuclear envelope: Double membrane with pores regulating nuclear-cytoplasmic exchange.
    • Chromosomes: DNA organized into chromosomes during cell division.
    • Nucleolus: Ribosome production site.

    Metabolic Reactions

    • Metabolism encompasses all biochemical processes.
      • Anabolism: Synthesis of complex molecules from simpler ones (requires energy).
      • Catabolism: Breakdown of complex molecules into simpler ones (releases energy).
      • Oxidation-reduction (redox) reactions: Electron transfer between molecules.
      • Hydrolysis reactions: Breakdown of bonds using water.
      • Phosphorylation/dephosphorylation: Addition/removal of phosphate groups for regulation.

    Functional Groups in Biomolecules

    • Functional groups are specific arrangements of atoms conferring unique properties to biomolecules. Examples include hydroxyl (-OH), carbonyl (C=O), carboxyl (-COOH), amino (-NH2), phosphate (-PO4), sulfhydryl (-SH), methyl (-CH3), amide (CONH2), and ester groups.

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    Description

    Explore the fundamental concepts of cell biology, focusing on the cellular basis of life, including the differences between prokaryotic and eukaryotic cells. This quiz highlights the structure and functions of animal cells, their membranes, and transport mechanisms. Test your understanding of how cells communicate and regulate their internal environments.

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