Cell Cycle Quiz for Biology Class 10
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Questions and Answers

What occurs during the S phase of the cell cycle?

  • The cell undergoes mitosis.
  • Cell size decreases.
  • Chromosomes are duplicated. (correct)
  • The cell prepares for energy production.

    • Which statement accurately describes the G2 phase of the cell cycle?

  • Cell growth resumes and energy is pooled.
  • Checkpoint mechanisms ensure readiness for mitosis. (correct)
  • DNA synthesis takes place.
  • The cell undergoes apoptosis.

    • What is the primary role of the checkpoint in the middle of mitosis?

  • To initiate cellular energy production.
  • To ensure proper alignment of chromosomes. (correct)
  • To replicate organelles.
  • To prevent DNA damage during synthesis.

    • How long does interphase constitute in the cell cycle?

    <p>About 90% of the cell cycle.</p> Signup and view all the answers

    During which phase does the cell focus energy on preparing for division and stop growing?

    <p>G2 phase.</p> Signup and view all the answers

    What are the two basic functions of the cell cycle?

    <p>Copying cellular components and cell division</p> Signup and view all the answers

    In which phase of the cell cycle does the cell grow and copy chromosomes in preparation for division?

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

    Why is cell division crucial for multicellular organisms?

    <p>It allows for growth and repair of tissues.</p> Signup and view all the answers

    Which cells in the human body typically do not undergo division?

    <p>Eye lens cells and nerve cells</p> Signup and view all the answers

    What phase directly follows the G1 phase in the cell cycle?

    <p>S phase</p> Signup and view all the answers

    What term describes the resting phase where the cell has exited the cycle and is not dividing?

    <p>Quiescent phase</p> Signup and view all the answers

    What is the main event that occurs during the M phase of the cell cycle?

    <p>Mitosis and cytokinesis</p> Signup and view all the answers

    Which component is distributed evenly to the daughter cells during cell division?

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

    What characterizes the G1 phase of the cell cycle?

    <p>Cell growth and metabolic activities take place.</p> Signup and view all the answers

    In what direction does DNA replication proceed?

    <p>5’ to 3’ direction</p> Signup and view all the answers

    What is a requirement for the initiation of DNA replication?

    <p>An RNA primer</p> Signup and view all the answers

    What type of process is DNA replication characterized as?

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

    Which feature is NOT characteristic of DNA replication?

    <p>It is a uni-enzymatic process</p> Signup and view all the answers

    What are duplicated chromosomes held together by after DNA replication?

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

    Which statement accurately describes the nature of the S-phase?

    <p>It includes DNA replication and centrosome duplication.</p> Signup and view all the answers

    What ultimately results from the process of DNA replication?

    <p>Identical copies of DNA strands</p> Signup and view all the answers

    What role do cyclins play in the cell cycle?

    <p>They activate cyclin-dependent kinase enzymes</p> Signup and view all the answers

    Which of the following statements about cancer cells is true?

    <p>They may convey growth signals without the presence of growth factors</p> Signup and view all the answers

    What is the primary function of Maturation Promoting Factor (MPF)?

    <p>To promote entrance into mitosis from G2 phase</p> Signup and view all the answers

    Which cyclin is paired with Cdk4 in the G1 phase?

    <p>Cyclin D</p> Signup and view all the answers

    Which of the following is NOT a characteristic of the cell cycle?

    <p>It allows for variation in DNA replication timing</p> Signup and view all the answers

    What is the role of cyclin-dependent kinases (cdks) in cell cycle regulation?

    <p>To regulate cell cycle progression</p> Signup and view all the answers

    What happens during the G1 checkpoint in the cell cycle?

    <p>Cells are checked for size and DNA integrity</p> Signup and view all the answers

    Which statement best describes the relationship between cyclins and cdks?

    <p>Cyclins and cdks form a complex to regulate the cell cycle</p> Signup and view all the answers

    What is the primary function of the kinetochore during cell division?

    <p>To bind microtubules and facilitate the separation of sister chromatids</p> Signup and view all the answers

    Which phase of the cell cycle is characterized by the synthesis of cell structures needed for division?

    <p>G2 phase</p> Signup and view all the answers

    What occurs during the metaphase of mitosis?

    <p>Chromosomes line up at the metaphase plate.</p> Signup and view all the answers

    What significant role does the centrosome play in cell division?

    <p>It organizes the spindle fibers essential for chromosome movement.</p> Signup and view all the answers

    In which phase do the sister chromatids become individual chromosomes?

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

    What is the main purpose of the cell cycle control system?

    <p>To direct the sequential events of the cell cycle and manage checkpoints</p> Signup and view all the answers

    Which structure forms during telophase to enclose the chromosome sets?

    <p>Nuclear envelope</p> Signup and view all the answers

    What is the result of cytokinesis in the cell cycle?

    <p>The separation of the cytoplasm into two daughter cells</p> Signup and view all the answers

    During which phase of mitosis do spindle fibers attach to kinetochores?

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

    Which of the following statements about daughter cells formed after mitosis is correct?

    <p>They are identical to each other and to the parent cell.</p> Signup and view all the answers

    What role do positive cues play in the cell cycle?

    <p>They increase the activity of Cdks and cyclins.</p> Signup and view all the answers

    At which checkpoint does the cell cycle predominantly assess DNA integrity before moving to division?

    <p>G2 checkpoint</p> Signup and view all the answers

    Which of the following phases is characterized by the nuclear envelope breaking down?

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

    What is primarily regulated by Cdks and cyclins during the cell cycle?

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

    Which component is NOT directly responsible for the regulatory processes of the cell cycle?

    <p>DNA ligase</p> Signup and view all the answers

    Which transition is specifically influenced by negative cues such as DNA damage?

    <p>G2 to M transition</p> Signup and view all the answers

    Which molecule primarily acts as a kinase to promote cell cycle progression?

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

    During which phase is DNA replicated in the cell cycle?

    <p>S phase</p> Signup and view all the answers

    Study Notes

    The Cell Cycle and Its Control

    • Cells are derived from pre-existing cells
    • Cell cycle: an ordered sequence of events in a cell preparing for division
    • Function of cell cycle: copying cellular components and DNA duplication, dividing the cell into daughter cells with even distribution of components.
    • Cell division is a crucial part of the cell cycle
    • Cell division occurs in unicellular organisms for reproduction
    • In multicellular organisms, cell division is for growth, creating new cells, and repairing existing ones (e.g., liver, skin)
    • Not all cells can divide, some cells like nerve cells, heart cells, and eye lens cells are maintained throughout adult life

    Stages of the Cell Cycle

    • Interphase (about 90% of the cell cycle):
      • G1 phase: cell growth, normal cell function, organelle duplication, protein synthesis, preparing for DNA replication, making proteins to duplicate the cellular components and DNA
      • S phase: DNA replication, chromosomes duplicate, forming sister chromatids connected by the centromere
      • G2 phase: final growth phase, preparing for mitosis (cell division). synthesizing cellular components (cytoplasm and organelles) needed for division
    • Mitosis: process of nuclear division
      • Prophase: preparation for chromosome separation
      • Prometaphase: breakdown of nuclear membrane and nucleolus, chromosomes condense, and spindle fibers form connecting to centromeres
      • Metaphase: chromosomes align in the middle (metaphase plate)
      • Anaphase: sister chromatids separate and move to opposite poles of the cell, pulled by spindle fibers attached to kinetochores
      • Telophase: nuclear envelopes form around each set of chromatids at opposite poles, chromosomes decondense, nucleolus reappears, spindle fibers disappear
    • Cytokinesis: division of the cytoplasm, creating two daughter cells

    DNA Replication

    • DNA replication: a semi-conservative process where DNA strands serve as templates for new strands, with each new DNA molecule consisting of one original and one new strand, creating identical DNA strands.
    • Base pairing allows each strand to serve as a template for a new strand.
    • Involved in several enzymes and proteins (Replisome)
    • Semiconservative: Watson and Crick base pairing maintained
    • 5' to 3' direction of synthesis
    • Initiation involves a primer, a complex process involving several enzymes and proteins (Replisome)

    Cell Cycle Control System

    • The sequential events of the cell cycle are directed by a distinct cell cycle control system.
    • The system is similar to a clock.
    • The cell cycle control system is regulated by both internal and external controls.
    • The clock has specific checkpoints where the cycle stops until a go-ahead signal is received.

    Checkpoints in the Cell Cycle

    • G1 checkpoint (restriction point): makes decision to divide or not based on conditions and also checks if DNA is damaged. If DNA is damaged then it does not proceed to division.
    • G2 checkpoint: determines if DNA replication has occurred correctly or if there was any damage. If conditions are not favourable the cells stop division
    • Metaphase checkpoint: ensures that all kinetochores are attached to the microtubules of the mitotic spindle before sister chromatids separate. It ensures that all of the chromosomes are properly attached to spindles before being divided.

    Molecules Involved in Cell Cycle Control

    • Cyclins: proteins that activate cyclin-dependent kinases (Cdks). Their concentrations fluctuate cyclically throughout the cell cycle.
    • Cyclin-dependent kinases (Cdks): enzymes that drive cell cycle events, activated by cyclins.

    Maturation Promoting Factor (MPF)

    • Heterodimeric protein composed of cyclin B & cyclin-dependent kinase (CDK1)
    • Promotes entrance into mitosis (M phase) from G2 phase.
    • Phosphorylates multiple proteins needed during mitosis.

    Cancer Cells and Cell Cycle Control

    • Cancer cells do not respond normally to the body's control mechanisms.
    • They may not need growth factors to grow and divide or may have an abnormal cell cycle control system. This can lead to uncontrolled cell growth, which is a characteristic of cancer.

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    Related Documents

    The Cell Cycle and Its Control PJ1311 PDF

    Description

    Test your knowledge about the various phases of the cell cycle, including interphase and mitosis. This quiz covers key functions, roles, and events that occur during each phase, from the G1 phase through to cell division. Perfect for biology students looking to reinforce their understanding of cell biology.

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