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Biology Chapter 5 Quiz
51 Questions
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Biology Chapter 5 Quiz

Created by
@EvaluativeQuantum

Questions and Answers

Which of the following cell structures exhibits selective permeability between a cell and its external environment?

  • Nucleus
  • Cell wall
  • Cytoplasm
  • Plasma membrane (correct)

    • Which of the following statements about the role of phospholipids in the structure and function of biological membranes is correct?

  • Phospholipids form a selectively permeable structure (correct)
  • Phospholipids have no role in membranes
  • Phospholipids prevent all substances from entering the cell
  • Phospholipids are rigid structures

    • The plasma membrane is referred to as a fluid mosaic structure. Which of the following statements about that model is true?

  • Phospholipids are fixed in place.
  • The membrane has no proteins.
  • Phospholipids can move laterally and proteins contribute to the mosaic aspect. (correct)
  • The membrane is completely static.

    • Consider the currently accepted fluid mosaic model of the plasma membrane. Where in the plasma membrane would cholesterol most likely be found?

    <p>Wedged between phospholipid molecules in the interior of the membrane</p> Signup and view all the answers

    Which of the following functional processes is not a consequence of the association of proteins with biological membranes?

    <p>Energy, carbon, and nitrogen storage</p> Signup and view all the answers

    Which of the following statements concerning carbohydrates associated with the plasma membrane is correct?

    <p>Membrane carbohydrates function primarily in cell-cell recognition.</p> Signup and view all the answers

    Where in the membrane would carbohydrates most likely be found?

    <p>On the outside (external) surface of the membrane</p> Signup and view all the answers

    Which statements about the sidedness of the plasma membrane is/are correct?

    <p>All of the listed responses are correct.</p> Signup and view all the answers

    Which of the following molecules is most likely to passively diffuse across the plasma membrane?

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

    Which of the following structural arrangements of the components in biological membranes is most consistent with the membrane's property of selective permeability?

    <p>Proteins embedded in two layers of phospholipid</p> Signup and view all the answers

    Which of the following statements about passive transport is correct?

    <p>It permits the solute to move in either direction, but net movement occurs down the concentration gradient.</p> Signup and view all the answers

    Oxygen will diffuse more rapidly into cell __________ because __________.

    <p>B...the diffusion gradient in cell B is steeper</p> Signup and view all the answers

    Diffusion is a passive process of a substance across a membrane with energy investment.

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

    To demonstrate plasmolysis, it would be necessary to suspend the cell in what solution?

    <p>1.0 M</p> Signup and view all the answers

    A single plant cell is placed in an isotonic solution. Salt is then added to the solution. Which of the following would occur as a result of the salt addition?

    <p>Water would leave the cell by osmosis, causing the volume of the cytoplasm to decrease.</p> Signup and view all the answers

    Which of these statements describes some aspect of facilitated diffusion?

    <p>It may occur through channel or transport proteins in the membrane.</p> Signup and view all the answers

    Facilitated diffusion requires the hydrolysis of ATP.

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

    Osmosis would cause red blood cells to shrink the most when immersed in which of the following solutions?

    <p>A hypertonic sucrose solution</p> Signup and view all the answers

    How does the preservation of green olives in brine, a 30% salt solution, prevent microorganisms from growing in the olives?

    <p>A 30% salt solution is hypertonic to the bacteria, so they lose too much water and plasmolyze.</p> Signup and view all the answers

    Based on the information that active transport requires energy and can generate voltages across membranes, which of the following statements is true?

    <p>The sodium/potassium pump hydrolyzes ATP and results in a net charge of +1 outside the cell membrane.</p> Signup and view all the answers

    Which of the following is a correct 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 of the following best describes a mechanism by which Ca2+ enters the cell?

    <p>Facilitated diffusion of Ca2+ into the cell down its electrochemical gradient</p> Signup and view all the answers

    Which of the following correctly describes a general property of all electrogenic pumps?

    <p>They create a voltage difference across the membrane.</p> Signup and view all the answers

    Which of the following statements about cotransport of solutes across a membrane is correct?

    <p>Cotransport proteins can couple the 'downhill' diffusion of the solute to the 'uphill' transport of a second substance against its own concentration gradient.</p> Signup and view all the answers

    Consider the transport of protons and sucrose into a plant cell by the sucrose-proton cotransport protein. Why, in the absence of sucrose, don't protons move back into the cell through the sucrose-proton cotransport protein?

    <p>The movement of protons through the cotransport protein cannot occur unless sucrose also moves at the same time.</p> Signup and view all the answers

    Which of the following enables a cell to pick up and concentrate a specific kind of molecule?

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

    Which of the following processes and organelles account for the replacement of lipids and proteins lost from the plasma membrane?

    <p>Exocytosis and rough and smooth ER</p> Signup and view all the answers

    How do large protein molecules, such as antibodies, enter the cells lining the baby's digestive tract?

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

    Which of the following pairs correctly matches a membrane transport process to its primary function?

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

    When a platelet contacts a damaged blood vessel, it is stimulated to release thromboxane A2. Thromboxane A2 in turn stimulates vascular spasm and attracts additional platelets to the injured site. In this example thromboxane A2 is acting as a __________.

    <p>local regulator</p> Signup and view all the answers

    Early work on signal transduction and glycogen metabolism by Sutherland indicated that __________.

    <p>the signal molecule did not interact directly with the cytosolic enzyme, but required an intact plasma membrane before the enzyme could be activated</p> Signup and view all the answers

    Testosterone and estrogen are lipid-soluble signal molecules that cross the plasma membrane by simple diffusion. If these molecules can enter all cells, why do only specific cells respond to their presence? __________.

    <p>Nontarget cells lack the intracellular receptors that, when activated by the signal molecule, can interact with genes in the cell's nucleus.</p> Signup and view all the answers

    Steroid hormones can enter a cell by simple diffusion. Therefore, steroids __________.

    <p>do not initiate cell signaling by interacting with a receptor in the plasma membrane.</p> Signup and view all the answers

    Steroid hormones can enter a cell by simple diffusion. Therefore steroids __________.

    <p>None of the listed responses is correct</p> Signup and view all the answers

    Receptors for signal molecules __________.

    <p>May be found embedded in the plasma membrane, or found within the cytoplasm or nucleus</p> Signup and view all the answers

    Testosterone does NOT affect all cells of the body because __________.

    <p>not all cells have cytoplasmic receptors for testosterone.</p> Signup and view all the answers

    Nitric oxide is unusual among animal signal molecules in that it __________.

    <p>is a gas.</p> Signup and view all the answers

    A G protein is active when __________.

    <p>GTP is bound to it.</p> Signup and view all the answers

    What event would activate a G protein? __________.

    <p>replacement of GDP with GTP.</p> Signup and view all the answers

    Ras, a small G protein located at the plasma membrane, is often mutated in different types of cancer. Ras normally signals to a cell that it should divide. Cancer cells divide uncontrollably. Which of the following changes to Ras would you expect to see in a cancer cell that has mutated Ras present?

    <p>It cannot hydrolyze GTP to GDP.</p> Signup and view all the answers

    The cellular response of a signal pathway that terminates at a transcription factor would be __________.

    <p>the synthesis of mRNA.</p> Signup and view all the answers

    What did Sutherland discover about glycogen metabolism in liver cells? __________.

    <p>The hormone that breaks down glycogen into glucose enters the liver cell.</p> Signup and view all the answers

    The general name for an enzyme that transfers phosphate groups from ATP to a protein is __________.

    <p>protein kinase.</p> Signup and view all the answers

    If ATPgammaS is a form of ATP that cannot be hydrolyzed by enzymes. If this compound was introduced to cells so that it replaced the normal ATP present in the cell, which of the following would you predict? __________.

    <p>a decrease in phosphorylated proteins in the cell.</p> Signup and view all the answers

    What does the addition of a phosphate group do to a protein? __________.

    <p>can either activate or inactivate a protein.</p> Signup and view all the answers

    The source of phosphate for a phosphorylation cascade is __________.

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

    Second messengers tend to be water-soluble and small. This accounts for their ability to __________.

    <p>rapidly move throughout the cell by diffusion.</p> Signup and view all the answers

    CAMP usually directly activates __________.

    <p>protein kinase A.</p> Signup and view all the answers

    A mutation in the active site of adenylyl cyclase that inactivates it would most likely lead to __________.

    <p>lower activity of protein kinase A.</p> Signup and view all the answers

    In eukaryotic cells, which of the following is a second messenger that is produced as a response to an external signal such as a hormone?

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

    Study Notes

    Plasma Membrane and Selective Permeability

    • The plasma membrane features selective permeability, regulating the passage of substances between the cell and its environment.
    • Phospholipids create a selectively permeable layer, essential for membrane structure and function.
    • The fluid mosaic model describes the plasma membrane's dynamic nature due to phospholipid movement and the embedded proteins that contribute to its mosaic appearance.

    Membrane Composition and Structure

    • Cholesterol is located between phospholipid molecules, aiding membrane fluidity.
    • Membrane carbohydrates primarily serve for cell-cell recognition and are situated on the external surface of the membrane.
    • The asymmetrical distribution of membrane components is established during membrane assembly, influencing the specific orientation of integral proteins.

    Molecular Transport Mechanisms

    • Small nonpolar molecules like carbon dioxide can easily passively diffuse across the plasma membrane.
    • Large polar molecules require transport proteins to diffuse through the membrane effectively.
    • The arrangement of proteins within two layers of phospholipids enhances selective permeability.

    Passive and Active Transport

    • Passive transport allows solutes to move down their concentration gradients without energy expenditure.
    • Oxygen diffuses more rapidly into actively respiring cells, where the concentration gradient is steeper.
    • Osmosis causes plant cells to lose water in hypertonic solutions, leading to potential plasmolysis.

    Facilitated Diffusion and Ion Transport

    • Facilitated diffusion utilizes channel or transport proteins to assist solute movement, not requiring ATP.
    • Red blood cells shrink when placed in a hypertonic sucrose solution due to osmosis.
    • The sodium/potassium pump hydrolyzes ATP, generating a charge difference across the membrane.

    Signal Reception and Transduction

    • Endocytosis mechanisms enable cells to concentrate specific molecules, while receptor-mediated endocytosis is one method to uptake large proteins like antibodies.
    • Specific cells respond to steroid hormones because they possess the necessary intracellular receptors.
    • Activated G proteins yield a cellular response upon binding GTP, which replaces GDP.

    Cellular Responses and Enzyme Activity

    • A phosphorylation cascade is critical in signaling pathways, utilizing ATP as the phosphate source.
    • The addition of a phosphate group can modulate the activity of proteins, either activating or deactivating them.
    • cAMP functions as a second messenger, typically activating protein kinase A.

    Cancer Signaling and Enzymatic Functions

    • Mutations in signaling proteins, like Ras, can lead to uncontrolled cell division, a hallmark of cancer.
    • Protein kinases transfer phosphate groups from ATP to proteins, playing roles in various signaling pathways.
    • Adenylyl cyclase activation facilitates increased kinase activity, which would be disrupted by mutations that inactivate it.

    Summary of Key Functions

    • Membrane transport processes include pinocytosis, active transport (against gradients), and facilitated diffusion, facilitating various cellular functions.
    • The interplay of hormones, receptors, and intracellular signals orchestrates complex responses within cells, highlighting the intricate nature of cellular communication and metabolism.

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    Description

    Test your knowledge with this quiz focused on Chapter 5 of biology, covering cell structures and the plasma membrane. Determine your understanding of key concepts such as selective permeability and the role of phospholipids in biological membranes.

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