Cell Cycle and Reproduction Quiz
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Questions and Answers

What is the primary role of the aster fibers during metaphase?

  • They attach to the chromosomes and pull them apart.
  • They help position the chromosomes along the center of the cell. (correct)
  • They assist in the formation of the nuclear membrane.
  • They condense the DNA into chromosomes.

    • What is the significance of the disappearance of the nuclear membrane during prometaphase?

  • It allows the chromosomes to condense more effectively.
  • It initiates the breakdown of the centrioles.
  • It enables the spindle fibers to attach to the chromosomes. (correct)
  • It triggers the formation of the cleavage furrow.

    • In which phase of mitosis does the separation of sister chromatids occur?

  • Prophase
  • Metaphase
  • Telophase
  • Anaphase (correct)

    • What is the name of the process by which a cell splits into two daughter cells?

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

    Why is DNA packaging such a critical process in mitosis?

    <p>It allows for the efficient separation of chromosomes. (B)</p> Signup and view all the answers

    What is the multi-hit hypothesis related to?

    <p>The development of cancer through multiple genetic mutations. (C)</p> Signup and view all the answers

    What characteristic distinguishes cancer cells from normal cells?

    <p>Cancer cells undergo uncontrolled division without stopping at G0. (B)</p> Signup and view all the answers

    Which of the following mutations could potentially contribute to cancer development?

    <p>All of the above. (D)</p> Signup and view all the answers

    Which of the following is NOT part of the G1 checkpoint?

    <p>Replicated DNA is inspected for damage (A)</p> Signup and view all the answers

    What is the primary function of the S phase in the cell cycle?

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

    Why is DNA copied before mitosis occurs?

    <p>To ensure each resulting daughter cell has a complete set of genetic material (D)</p> Signup and view all the answers

    What is the primary difference between binary fission and mitosis?

    <p>Binary fission occurs in prokaryotes, while mitosis occurs in eukaryotes. (A)</p> Signup and view all the answers

    During which phase of mitosis does the nuclear envelope reassemble and chromosomes begin to decondense?

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

    Study Notes

    Cell Cycle and Cell Reproduction

    • Cell reproduction in prokaryotes occurs via binary fission: DNA is copied, and the cell splits into two.
    • Most bacteria can divide quickly, often with multiple copies of their chromosomes already formed.
    • Reproduction speed varies greatly. E. coli can reproduce in about 20 minutes, and other types in 16-18 minutes.

    Cell Division in Eukaryotes

    • The cell cycle is a series of events in eukaryotic cells that leads to cell division. The cycle includes mitosis and cytokinesis.
    • The cell cycle has specific phases: G1 (growth), S (synthesis of DNA), G2 (growth), and mitosis (division of the nucleus).
    • At the G1 checkpoint, the cell can enter a non-dividing state called G0.
    • During S phase, the cell makes a copy of all of its DNA.
    • During G2 phase, the cell stockpiles the energy (like ATP) and other components it needs to divide.

    The Cell Cycle

    • Mitosis and cytokinesis are both essential parts of the cell cycle for eukaryotic cell reproduction.

    Cell Reproduction in Eukaryotes

    • DNA is copied during the S phase before mitosis.
    • Mitosis is nuclear division.
    • Four stages of mitosis include: prophase & prometaphase, metaphase, anaphase, and telophase.
    • Cytokinesis is the division of the cytoplasm and other components of the cell.
    • The divisions result in two daughter cells. For example, the parent cell splits into two daughter cells

    Prophase & Prometaphase

    • Chromosomes condense.
    • Centrioles move to opposite ends of the cell.
    • Spindle fibers form from centrioles.
    • Nuclear envelope disappears (prometaphase).

    DNA Packaging

    • DNA (2 meters/6 feet long) must be compact to fit in the nucleus.
    • DNA is tightly wrapped around proteins called histones.
    • The histones then group together to form structures.

    Metaphase

    • Microtubules from centrioles pull and align chromosomes in the middle of the cell.
    • Chromosomes align along the center (metaphase plate) of the cell.
    • Chromosomal movement occurs via motor proteins along microtubules.

    Anaphase

    • The centromere splits, and sister chromatids pull apart.
    • Motor proteins move chromatids along microtubules, which disassemble as they shorten.

    Telophase

    • Nuclear membranes form around the DNA at each end of the cell, creating two nuclei.
    • The cell prepares to divide its cytoplasm.

    Cytokinesis

    • The cell splits.
    • A ring of protein forms around the equator of the cell.
    • The ring contracts, splitting the cell into two separate cells.

    Mitosis & Cytokinesis Animation & Video

    • Consult the Canvas site for animations of mitosis and cytokinesis.

    Mitosis & Cytokinesis Summary

    • This summarises the stages of mitosis and cytokinesis visualised by different stages of the phases.

    Cancer

    • Cancer is uncontrolled cell division.
    • Mutant cells divide continuously without stopping. They bypass the typical cell cycle checkpoints.
    • Large masses (tumors) form from fast-growing cells; the initial tumor is called the primary tumor.
    • Cancer cells can metastasize, spreading to other areas and forming secondary tumors.

    Getting Cancer

    • Cancer is due to multiple genetic mutations causing uncontrolled cell growth.
    • A multi-hit hypothesis suggests several mutations within the same cell are needed to develop cancer.
    • Mutations that cause cancer include: mutations that signal the cell to divide when it shouldn't, mutations that deactivate apoptosis (programmed cell death), mutations altering contact inhibition, and mutations that affect the ECM for metastasis.

    Factors that Can Increase the Risk for Cancer

    • Environmental factors such as chemicals, radiation, and viruses can cause DNA mutations, increasing the risk of cancer.
    • Genetics also play a role. Some people inherit a predisposition to cancer from their ancestors.

    Treating Cancer

    • Surgical excision can be used to remove primary tumors.
    • Chemotherapy uses drugs that target rapidly dividing cells, including cancer cells, to halt cell division and growth.
    • Radiation therapy uses ionizing radiation to damage cancer cells to kill cancer cells. This can also affect normal cells.
    • Immunotherapy aims to boost the immune system to fight cancer cells.

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    Related Documents

    Cell Cycle and Mitosis Student PDF

    Description

    Test your knowledge on the processes of cell reproduction and the cell cycle. This quiz covers the differences between prokaryotic and eukaryotic cell division, including the phases of the cell cycle and the mechanisms of mitosis and cytokinesis. Perfect for students studying biology concepts related to cellular processes.

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