Biology: Cell Structure and Function
38 Questions
2 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary function of membrane receptors?

  • To provide structure to the cell membrane
  • To synthesize proteins
  • To bind to specific extracellular molecules and cause a corresponding cellular response (correct)
  • To facilitate the passage of molecules through the membrane
  • What is the typical composition of membrane-spanning components of membrane receptors?

  • Alpha helices (correct)
  • Cytoplasmic organelles
  • Beta sheets
  • Beta barrels
  • What is the function of ligands in cellular signaling?

  • To provide structure to the cell membrane
  • To facilitate the passage of molecules through the membrane
  • To bind to receptors to produce an intercellular signal (correct)
  • To synthesize proteins
  • What is the purpose of channels in cellular membranes?

    <p>To facilitate the passage of molecules through the membrane that wouldn't be able to otherwise</p> Signup and view all the answers

    What is the composition of channels in cellular membranes?

    <p>Beta barrels</p> Signup and view all the answers

    What is the function of the cytosol in cellular structure?

    <p>To suspend organelles in the cell</p> Signup and view all the answers

    What type of amino acids would be present in the intramembranous domains of membrane receptors?

    <p>Hydrophobic/nonpolar amino acids</p> Signup and view all the answers

    What type of amino acids would be present in the intra- and extracellular domains of membrane receptors?

    <p>Polar/charged amino acids</p> Signup and view all the answers

    What is the unit of osmotic pressure?

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

    Which of the following increases the osmotic pressure of a solution?

    <p>Increasing the molarity of the solution</p> Signup and view all the answers

    What is the role of van't Hoff factor in osmotic pressure?

    <p>It represents the number of ions formed by the solute</p> Signup and view all the answers

    What is the primary purpose of the plasma membrane in a cell?

    <p>To separate the external and internal environments of the cell, allowing for homeostasis</p> Signup and view all the answers

    What is the characteristic of phospholipids that allows them to form a lipid bilayer?

    <p>Their amphipathic nature, with a charged phosphate head and hydrocarbon tails</p> Signup and view all the answers

    In which direction will water flow when a cell with a higher osmotic pressure is placed in a solution with a lower osmotic pressure?

    <p>Into the cell</p> Signup and view all the answers

    What is the purpose of facilitated diffusion in a cell?

    <p>To allow polar molecules or charged ions to cross the plasma membrane</p> Signup and view all the answers

    What is the function of cholesterol in the plasma membrane of eukaryotic cells?

    <p>To maintain consistency in membrane performance in a wide range of temperatures</p> Signup and view all the answers

    What is the term for areas in the plasma membrane with high concentrations of cholesterol?

    <p>Lipid rafts</p> Signup and view all the answers

    What is the driving force behind spontaneous movement of molecules?

    <p>The concentration gradient</p> Signup and view all the answers

    What is the main difference between peripheral and integral proteins in the plasma membrane?

    <p>Their location in the membrane, with peripheral proteins attaching to one side and integral proteins spanning the entire membrane</p> Signup and view all the answers

    Which of the following is an example of facilitated diffusion?

    <p>Passage of glucose across the plasma membrane</p> Signup and view all the answers

    What will happen to a cell placed in a hypertonic solution?

    <p>Water will flow out of the cell</p> Signup and view all the answers

    What is the term for proteins that span the entire plasma membrane and have both extracellular and intracellular domains?

    <p>Transmembrane proteins</p> Signup and view all the answers

    Why do prokaryotes not use cholesterol in their plasma membrane?

    <p>Because they use hopanoids instead, which provide similar functionality</p> Signup and view all the answers

    What is the term for the smallest unit of self-sustainable life?

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

    What is the result of the hydrolysis of ATP?

    <p>ADP + Pi + H2O</p> Signup and view all the answers

    What is the primary source of energy for biological reactions?

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

    What is the function of Na+/K+ ATPase?

    <p>To pump 3 Na+ ions out and 2 K+ ions into the cell</p> Signup and view all the answers

    What is the purpose of secondary active transport?

    <p>To utilize the gradient established by active transport</p> Signup and view all the answers

    What type of amino acids would be present in the core of a Ca2+ channel?

    <p>Negatively charged or dipole amino acids</p> Signup and view all the answers

    What is the process of releasing cellular contents into the extracellular environment?

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

    What is the energy yield of ATP hydrolysis?

    <p>-30 kJ/mol</p> Signup and view all the answers

    What is the purpose of active transport?

    <p>To use ATP to pump ions against their gradient</p> Signup and view all the answers

    What is the primary function of endocytosis in a cell?

    <p>To release extracellular molecules into the cell</p> Signup and view all the answers

    What type of transport is exocytosis and endocytosis an example of?

    <p>Active transport</p> Signup and view all the answers

    What is the name of the protein used to create vesicles in exocytosis and endocytosis?

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

    What is the main difference between symport and antiport transportation?

    <p>The direction of molecule movement</p> Signup and view all the answers

    What is the purpose of symport and antiport transportation?

    <p>To move molecules against their concentration gradient</p> Signup and view all the answers

    What is the term for vesicles produced in exocytosis?

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

    Study Notes

    The Cell

    • The cell is the smallest unit of self-sustainable life.

    Plasma Membrane

    • Composed of a lipid bilayer, separating external and internal environments to maintain homeostasis.
    • Phospholipids have an amphipathic nature, with a charged phosphate head and hydrocarbon tails.
    • Cholesterol is used by eukaryotes to maintain consistency in membrane performance at various temperatures.
    • Lipid rafts are areas in the membrane with high concentrations of cholesterol, surrounding proteins or other membrane components.

    Proteins

    • Peripheral proteins attach to one side of the membrane, either externally or internally.
    • Integral proteins, also called transmembrane proteins, span the entire membrane with both extracellular and intracellular domains.
    • Membrane receptors are integral proteins that bind to specific extracellular molecules, causing a corresponding cellular response.
    • Channels allow for the passage of molecules through the membrane, composed of beta barrels, and each type allows passage of a different substance.

    Cytoplasm

    • The entire interior of the cell, including organelles and cytosol.
    • Cytosol is the gel-like portion suspending organelles, composed of water, ions, proteins, etc.

    Osmotic Pressure

    • The pressure needed to prevent the inward flow of water from a pure solution across a semipermeable membrane.
    • Described by the equation: π = iMRT, where π is the osmotic pressure, i is van't Hoff's factor, M is the molarity of the solution, R is the ideal gas law constant, and T is the temperature in Kelvin.

    Facilitated Diffusion

    • Passage of polar molecules or charged ions through a protein channel or carrier.
    • Molecules move from areas of high concentration (or charge) to areas of low concentration (or charge), down an electrochemical gradient.

    Active Transport

    • Energy is used to move solutes against their electrochemical gradient.
    • ATP is the primary source of energy for biological reactions, produced by the cell.
    • Na+/K+ ATPase pumps 3 Na+ ions out of the cell and 2 K+ ions into the cell, against their chemical gradients.

    Exocytosis and Endocytosis

    • Exocytosis: Cellular contents are packaged in a vesicle and released into the extracellular environment.
    • Endocytosis: A vesicle containing extracellular molecules fuses with the plasma membrane and releases its contents into the cell.

    Symport and Antiport

    • Both utilize the movement of one molecule with its gradient to transport another molecule against its respective gradient.
    • Symporters move both molecules in the same direction, while antiporters move them in opposite directions.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    Learn about the components of a cell and their roles in making life possible. This quiz covers the plasma membrane, its purpose, and how it maintains homeostasis.

    More Like This

    Use Quizgecko on...
    Browser
    Browser