BIOS222 Exam 4 Study Guide
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Questions and Answers

What function do synaptic vesicles primarily serve in neural communication?

  • Cell adhesion
  • Regulated secretion (correct)
  • Signal amplification
  • Electrical signaling

    • Where do synaptic vesicles release their contents during synaptic transmission?

  • The axon
  • The postsynaptic cell cytoplasm
  • The presynaptic cell cytoplasm
  • The synaptic cleft (correct)

    • In epithelial cells, where are microvilli primarily located?

  • Lateral domain
  • Apical domain (correct)
  • Basal domain
  • Basolateral domain

    • Which cell junction prevents molecules from diffusing between cells in epithelial tissues?

    <p>Tight junction</p> Signup and view all the answers

    Which type of cell junction is associated with a belt of actin filaments?

    <p>Adherens junction</p> Signup and view all the answers

    What type of transmembrane protein binds to the same domain on adjacent cells?

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

    What is the primary role of gap junctions between cells?

    <p>Communication via small molecules</p> Signup and view all the answers

    What type of cell nucleus can be replaced to clone a frog according to John Gurdon's research?

    <p>Adult skin cell</p> Signup and view all the answers

    What part of the receptor is phosphorylated on tyrosine upon activation of a receptor tyrosine kinase?

    <p>The cytoplasmic domain of the receptor</p> Signup and view all the answers

    How does Viagra affect cellular signaling?

    <p>Delaying the end of the activated state of signaling</p> Signup and view all the answers

    Which signaling pathway is influenced by the action of Viagra?

    <p>Nitric oxide signaling</p> Signup and view all the answers

    Ras is identified as an intermediary in which signaling pathway?

    <p>Tyrosine kinase signaling</p> Signup and view all the answers

    Which process is NOT involved in resetting or turning off a signaling pathway?

    <p>A G alpha trimeric G protein replacing GDP with GTP</p> Signup and view all the answers

    Protein kinase A serves as an effector for which signaling pathway?

    <p>GPCR signaling through adenylyl cyclase</p> Signup and view all the answers

    What is true about both oncogenes and tumor suppressor genes in human populations?

    <p>Both tend to exhibit a gain of function in the mutant state</p> Signup and view all the answers

    Sound transduction by the outer hair cells of the inner ear occurs via which type of channels?

    <p>Mechanically gated ion channels</p> Signup and view all the answers

    What does Ross Cagans' research using transgenic flies demonstrate?

    <p>Expressing genes with mutations that cause cancer in humans also cause cancer in flies</p> Signup and view all the answers

    Oncogenes are mutant forms of which type of genes?

    <p>Genes that promote cell growth and division in normal cells</p> Signup and view all the answers

    Which of the following cell types is not considered pluripotent?

    <p>Adult skin cell</p> Signup and view all the answers

    What describes a stem cell that can only give rise to one specific differentiated cell type?

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

    Which statement about induced pluripotent stem (iPS) cells is false?

    <p>Require destruction of human embryos to produce them</p> Signup and view all the answers

    From where did Texas Governor Rick Perry's injected stem cells originate?

    <p>Fat tissue removed from his own body</p> Signup and view all the answers

    Why do defects in the retinoblastoma gene not always lead to cancer?

    <p>One copy of the gene is defective at birth, and the other copy mutates later.</p> Signup and view all the answers

    How does Viagra impact signal transduction?

    <p>It blocks a negative regulator of nitric oxide.</p> Signup and view all the answers

    What is a significant risk associated with introducing embryonic stem cells into an adult human body?

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

    What is the result of tyrosine kinase receptor activation?

    <p>Phosphotyrosine residues appear in the cytoplasmic domain.</p> Signup and view all the answers

    When are small GTP-binding proteins like Ras and Ran considered active?

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

    In which scenario does ligand binding lead to a change in enzyme activity inside the cell?

    <p>True in both pathways.</p> Signup and view all the answers

    In which pathway could the second messenger potentially be cAMP?

    <p>True in pathway 1.</p> Signup and view all the answers

    What can we infer about the nature of the ligand in pathway 1?

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

    Does the receptor in pathway 1 have 7 transmembrane domains?

    <p>Yes, pathway 1 notably has 7 domains.</p> Signup and view all the answers

    What type of molecules are known to normally put the brakes on the cell cycle?

    <p>Tumor suppressors</p> Signup and view all the answers

    Which molecule's binding to its receptor initiates the removal of the Rb block against cell cycle entry?

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

    What is a ligand?

    <p>A thing that binds to a thing</p> Signup and view all the answers

    cohesins are agents thaat link

    <p>sister chromatds to each other</p> Signup and view all the answers

    Phosphorylation by wee1 kinase has what kind of effect on the activity of M-CDK?

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

    Is it true that every signaling pathway requires its own unique ligand and receptor?

    <p>No, they can share ligands</p> Signup and view all the answers

    Which statement accurately describes the role of the p53 protein?

    <p>Tumor suppressor</p> Signup and view all the answers

    What is the likely outcome for an animal cell that is receiving no signals?

    <p>Is likely to die</p> Signup and view all the answers

    What is the main role of licensing factors in DNA replication?

    <p>Limits it to once per cycle</p> Signup and view all the answers

    Gbeta and Ggamma are typically found in what state?

    <p>Bound to Galpha in the resting state</p> Signup and view all the answers

    What is the primary role of condensins in cellular processes?

    <p>Chromatin condensation</p> Signup and view all the answers

    What is the primary role of a dimeric ligand?

    <p>Specifically activating enzyme coupled receptors</p> Signup and view all the answers

    Which aspect of kinetochore microtubules changes during anaphase?

    <p>Get shorter as anaphase proceeds</p> Signup and view all the answers

    How does a receptor tyrosine kinase primarily function?

    <p>Phosphorylating itself upon ligand binding</p> Signup and view all the answers

    Which substance was the first messenger in Earl Sutherland's work with cAMP?

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

    What is required for a receptor tyrosine kinase to return to its resting state?

    <p>Removal of phosphate by phosphatase</p> Signup and view all the answers

    treating a cell with an antibody against a receptor tyrosine kinase can cause it to form dimers leading to receptor

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

    M-CDK is most active when its

    <p>bound to cyclin</p> Signup and view all the answers

    Wee1 kinase

    <p>Adds an inhibitory phosphate to M-CDK</p> Signup and view all the answers

    phosphorylation of nuclear lamins is responsible for disassembly of the nuclear envelope at the start of mitosis. The kinase that is responsible is

    <p>M-CDK</p> Signup and view all the answers

    After replication of DNA, sister chromatids are held together by

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

    Retinoblastoma protein is a

    <p>Tumor suppressor</p> Signup and view all the answers

    DNA damage

    <p>Causes a pause in progress through the cell cycle</p> Signup and view all the answers

    Force production to segregate chromosomes at mitosis is provided through

    <p>Polar microtubules</p> Signup and view all the answers

    polar microtubules

    <p>get longer as anaphase proceeds</p> Signup and view all the answers

    At which of the following sites would you expect to see a plus-end-directed kinesin family member that contributes to anaphase chromosome movements

    <p>Polar microtubule overlapping region</p> Signup and view all the answers

    p53 is activated in response to DNA damage

    <p>By phosphorylation</p> Signup and view all the answers

    A chromosome can be plucked out of the spindle of a live cell undergoing mitosis. As a result:

    <p>division will be halted by spindle assembly checkpoint</p> Signup and view all the answers

    After replication of DNA, sister chromatids are held together by

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

    Astral microtubules contribute to

    <p>anaphase B chromosome movements</p> Signup and view all the answers

    A cell’s karyotype is best observed and evaluated at

    <p>Metaphase of mitosis</p> Signup and view all the answers

    An action potential begins with

    <p>the opening of voltage-dependent Na+ channels</p> Signup and view all the answers

    The chromosome movements of anaphase A of mitosis are based on

    <p>Shortening of population 6</p> Signup and view all the answers

    The time it takes to reset an action potential is

    <p>in the millisecond range</p> Signup and view all the answers

    Voltage gated calcium ion channels in the presynaptic membrane are responsible for

    <p>Release of neurotransmitter from the presynaptic cell</p> Signup and view all the answers

    Neurotransmitter gated ion channels

    <p>regenerate an action potential in the post synaptic cell</p> Signup and view all the answers

    Oncogenes arise by mutations in genes

    <p>That make growth stimuli uncontrolled</p> Signup and view all the answers

    A cell junction that attaches bundles of actin filaments to sites of cell-cell adhesion

    <p>Adherens junction</p> Signup and view all the answers

    Yamanaka looked for genes that would bestow “stemness” on cells that would express them. He found a combination of ____ genes.

    <p>4</p> Signup and view all the answers

    Which of these has the most potency (ie produces the most different differentiated cell types

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

    Blood cells like erythrocytes are derived from the same stem cell progenitor as neutrophils and macrophages

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

    Study Notes

    Exam 4 Study Guide - BIOS222

    • Ligand: A molecule that binds to a receptor, initiating a signaling pathway.
    • Signaling Pathway Characteristics: Every signaling pathway requires a unique ligand and receptor.
    • Animal Cell Response to No Signals: A cell receiving no signals is likely to die, unless it's a stem cell.
    • G-protein subunits (Gβγ): Active when bound to GTP. They are bound to Gα in the resting state.
    • Dimeric Ligands: Important for activating enzyme-coupled receptors, specifically affecting GPCRs.
    • Receptor Tyrosine Kinase (RTK): Can phosphorylate itself.
    • 2nd Messenger Discovery: Earl Sutherland discovered cAMP as a 2nd messenger.
    • Receptor Tyrosine Kinase Inhibition: Antibodies against receptor tyrosine kinases can lead to receptor dimer formation, activation, and downstream effects.
    • Inactivation (RTK): The return to the resting state is dependent on preventing further kinase activity, preventing further ligand binding, and removal of phosphates by phosphatases.
    • M-CDK Activity: Most active when its not phosphorylated at inhibitory sites, yet it's also bound to cyclin within the S phase of the cell cycle.
    • Wee1 Kinase: Adds an inhibitory phosphate to M-CDK.
    • Cell Cycle Brakes: Tumor suppressors put brakes on the cell cycle.
    • Cell Cycle Trigger: Mitogens initiate cell cycle events.
    • Nuclear Lamins Disassembly: Phosphorylation of nuclear lamins leads to nuclear envelope disassembly, a key aspect of mitosis initiation.
    • Sister Chromatid Connection: Cohesins hold sister chromatids together after DNA replication.
    • Phosphorylation Effect on M-CDK: Phosphorylation by Wee1 kinase has a negative effect on M-CDK activity.
    • P53 Protein: A tumor suppressor.
    • Retinoblastoma Protein (Rb): A tumor suppressor protein.
    • Licensing Factor Effect: A licensing factor limits DNA replication to one cycle per cell cycle.
    • Cohesins: Link sister chromatids to each other.
    • Condensing Agents (Condins): Responsible for chromatin condensation, which is crucial in apoptosis and cell division.
    • DNA Damage Response: DNA damage leads to cell cycle arrest and can induce apoptosis. P53's activation is a crucial part of the response.
    • Mitosis Force Production: Astral, kinetochore, and polar microtubules all contribute to chromosome segregation during mitosis.
    • Kinetochore Microtubules: Shorten during anaphase.
    • Polar Microtubules: Lengthen during anaphase.
    • Action Potential Reset: The resetting of an action potential occurs in the millisecond timescales.
    • Presynaptic Calcium and Neurotransmission: Voltage-gated calcium channels in the presynaptic membrane are crucial for neurotransmitter release.
    • Neurotransmitter Ions: Neurotransmitter gated ion channels are required to trigger action potentials.
    • Induced Pluripotent Stem (iPS) Cells: Stem cells that can be generated from adult cells and can develop into many different adult cell types without using embryonic stem cells.
    • Tyrosine Kinase Receptor Activation: Occurs via phosphotyrosine residues and the signaling pathway's downstream cytoplasmic components
    • Small GTP-Binding Proteins (GTPases): Active when bound to GTP. Inactive when bound to GDP.
    • Ligand Binding and Enzyme Activity: Ligand binding outside a cell can influence enzyme activity inside.
    • Second Messengers: Small molecules like cAMP, can act as second messengers within pathways.
    • Receptor Complexity: Certain receptors feature multiple transmembrane domains, important components of their signaling.
    • GTPase Activity: Inactivates the pathway's activity.
    • Cell-Cell Contact Proteins: Tight Junction (ZO), Adheren Junction (ZA), Desmosome influence cell-cell structure and communication.
    • Signal Transduction: The process by which a cell receives and interprets a signal.
    • Sounds and Inner Ear Hair Cells: Outer hair cells transduce sound via mechanically gated ion channels.
    • Viagra's Effect: Alters nitric oxide signaling pathways.

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    BIOS222 Exam 4 Study Guide Fall 2024 PDF

    Description

    Prepare for your BIOS222 Exam 4 with this comprehensive study guide focused on signaling pathways, ligand-receptor interactions, and key concepts like G-proteins and receptor tyrosine kinases. Understand the critical roles of second messengers and the implications of ligand binding and RTK inhibition in cellular responses. This guide is essential for mastering the chapter content and excelling in your exam.

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