Meiosis Overview and Genetic Variation
37 Questions
0 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 phase of the cell cycle is primarily involved in DNA replication?

  • S phase (correct)
  • G2 phase
  • G1 phase
  • Mitosis

    • Which of the following is NOT a characteristic of the G1 phase of interphase?

  • Organelles double
  • Cell size increases
  • Materials for DNA synthesis accumulate
  • DNA replication happens (correct)

    • What is apoptosis?

  • A stage in meiosis
  • A process that increases cell number
  • Programmed cell death involving cell fragmenting (correct)
  • A tumor-forming process in cancer

    • During which part of the cell cycle does cytokinesis occur?

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

    How do cancer cells differ from normal cells regarding cell cycle control?

    <p>They divide uncontrollably and form tumors</p> Signup and view all the answers

    What is the diploid number of chromosomes in humans?

    <p>46</p> Signup and view all the answers

    Which stage of the cell cycle is most associated with cell growth and organelle duplication?

    <p>G1 phase</p> Signup and view all the answers

    Which process reduces the chromosome number from diploid to haploid?

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

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

    <p>To monitor and regulate cell division</p> Signup and view all the answers

    What characterizes a benign tumor?

    <p>It does not spread to other body parts</p> Signup and view all the answers

    Which type of cell division contributes to genetic variation?

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

    What are homologous chromosomes?

    <p>A pair of chromosomes with the same length and inherited characters</p> Signup and view all the answers

    What typically occurs during the G2 phase of interphase?

    <p>Proteins necessary for division are synthesized</p> Signup and view all the answers

    What type of chromosomes do human females have?

    <p>Two X chromosomes</p> Signup and view all the answers

    Which of the following best describes binary fission?

    <p>A type of asexual reproduction in prokaryotes</p> Signup and view all the answers

    What is formed when an egg and sperm fuse during fertilization?

    <p>A diploid zygote</p> Signup and view all the answers

    What is the primary purpose of meiosis in eukaryotic organisms?

    <p>To create genetic diversity through haploid gamete production</p> Signup and view all the answers

    Which phase occurs during meiosis II?

    <p>Metaphase II</p> Signup and view all the answers

    How does crossing over contribute to genetic variation?

    <p>It exchanges genetic material between non-sister chromatids, producing recombinant chromosomes.</p> Signup and view all the answers

    In which phase do homologous chromosomes line up at the cell's equator?

    <p>Metaphase I</p> Signup and view all the answers

    What does independent assortment of chromosomes ensure during meiosis?

    <p>Maternal and paternal chromosomes segregate randomly into gametes.</p> Signup and view all the answers

    What characterizes the daughter cells produced at the end of meiosis?

    <p>They are haploid and genetically diverse.</p> Signup and view all the answers

    How many nuclear divisions are required in meiosis?

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

    What is the result of random fertilization in terms of genetic variation?

    <p>Generates about 70 trillion diploid combinations</p> Signup and view all the answers

    What is the formula for the number of possible combinations of chromosomes during independent assortment?

    <p>$2^n$ where n is the haploid number</p> Signup and view all the answers

    Which statement correctly describes the daughter cells produced by meiosis?

    <p>They are haploid and genetically different from the parent cell</p> Signup and view all the answers

    What initiates the process of crossing over during meiosis?

    <p>The pairing of homologous chromosomes in Prophase I</p> Signup and view all the answers

    Which phase of meiosis involves the formation of bivalents?

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

    During which phase do homologous chromosomes separate in meiosis?

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

    What is the function of histones in eukaryotic chromosomes?

    <p>To help organize DNA into chromatin</p> Signup and view all the answers

    During which phase of mitosis does the nuclear envelope disintegrate?

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

    What characterizes the diploid chromosome number in somatic cells?

    <p>It consists of two full sets of chromosomes.</p> Signup and view all the answers

    What is required for the attachment of spindle fibers during prometaphase?

    <p>Development of kinetochores on centromeres</p> Signup and view all the answers

    At which stage of mitosis do chromosomes line up at the metaphase plate?

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

    What is the main function of cytokinesis?

    <p>To divide the cytoplasm and complete cell division</p> Signup and view all the answers

    How does chromatin change during the preparation for mitosis?

    <p>It becomes highly coiled and condensed.</p> Signup and view all the answers

    How many chromosomes do human somatic cells have?

    <p>46</p> Signup and view all the answers

    Study Notes

    Meiosis Overview

    • Meiosis is a cell division process that reduces the chromosome number from diploid (2n) to haploid (n).
    • It is essential for sexual reproduction, producing gametes (sperm and egg) with half the number of chromosomes.
    • Meiosis consists of two successive nuclear divisions: Meiosis I and Meiosis II, each with four phases.
    • Daughter cells from meiosis become either gametes (sperm or egg) in animals or haploid spores in plants, which later produce gametes by mitosis.

    Mechanisms for Genetic Variation

    • Genetic variation during meiosis is achieved through three mechanisms:
      • Crossing Over: Exchange of genetic material between non-sister chromatids of homologous chromosomes during prophase I.
      • Independent Assortment of Chromosomes: Random orientation of homologous chromosome pairs at metaphase I, leading to different combinations of maternal and paternal chromosomes in daughter cells.
      • Random Fertilization: The fusion of any sperm with any egg increases the number of possible genetic combinations.

    Key Differences Between Mitosis and Meiosis

    • Number of Divisions: Mitosis involves one nuclear division, while meiosis involves two.
    • Daughter Cell Number: Mitosis produces two diploid daughter cells, while meiosis produces four haploid daughter cells.
    • Genetic Similarity: Mitosis produces daughter cells genetically identical to the parent cell, while meiosis produces daughter cells that are genetically different from each other and the parent cell.
    • Function: Mitosis is involved in growth, repair, and asexual reproduction, while meiosis is involved in producing gametes for sexual reproduction.
    • Crossing Over: Crossing over does not occur in mitosis, but it is a crucial event during prophase I of meiosis.
    • Chromosome Alignment: In mitosis, individual chromosomes align at the metaphase plate, while in meiosis I, bivalents (pairs of homologous chromosomes) align at the metaphase plate.
    • Chromosome Separation: In mitosis, sister chromatids separate during anaphase, becoming daughter chromosomes that move to opposite poles. In meiosis I, homologous chromosomes separate, with duplicated chromosomes moving to opposite poles.

    Studying That Suits You

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

    Quiz Team

    Related Documents

    Fundamentals Of Biology: Cell Cycle & Cellular Reproduction PDF

    Description

    Explore the key concepts of meiosis, a crucial process in sexual reproduction that reduces chromosome numbers to create gametes. Understanding genetic variation mechanisms such as crossing over, independent assortment, and random fertilization is essential for appreciating the diversity in living organisms.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser