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General Biology: Cell Cycle and Meiosis

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Termini in questo insieme (30)

  • What is the primary result of most cell division?
    Most cell division results in genetically identical daughter cells, ensuring continuity of life.
  • What are the key roles of cell division in multicellular eukaryotes?
    Cell division allows growth, development, renewal, and repair in multicellular eukaryotes.
  • How is genetic material organized in prokaryotes versus eukaryotes?
    Prokaryotes have a single circular chromosome; eukaryotes have multiple linear chromosomes.
  • What is the difference between chromatin and chromosomes?
    Chromatin is unpacked DNA accessible for use; chromosomes are condensed DNA packaged for cell division.
  • What are germ line cells and somatic cells?
    Germ line cells are diploid progenitors that produce haploid gametes by meiosis; somatic cells are all other diploid body cells.
  • What is the difference between haploid and diploid cells?
    Haploid cells contain one copy of each chromosome; diploid cells contain two copies of each chromosome.
  • What is the cell cycle and its main phases?
    The cell cycle includes interphase (G1, S, G2 phases) and M phase (mitosis and cytokinesis).
  • What happens during the S phase of the cell cycle?
    DNA is replicated in preparation for cell division.
  • What are the five stages of mitosis?
    Prophase, prometaphase, metaphase, anaphase, and telophase.
  • What occurs during prophase in mitosis?
    Chromatin condenses into chromosomes, nucleoli disappear, mitotic spindle forms, and centrosomes migrate.
  • What is the mitotic spindle and its function?
    A structure of microtubules that controls chromosome movement during mitosis.
  • What happens during metaphase of mitosis?
    Chromosomes align at the metaphase plate, each attached to spindle microtubules from opposite poles.
  • Describe anaphase in mitosis.
    Sister chromatids separate and are pulled to opposite poles as kinetochore microtubules shorten.
  • What occurs during telophase and cytokinesis?
    Nuclear envelope reforms, chromosomes decondense, and the cell divides into two daughter cells.
  • How does cytokinesis differ in animal and plant cells?
    Animals form a cleavage furrow using actin and myosin; plants form a cell plate from Golgi vesicles.
  • What is binary fission in prokaryotes?
    A form of asexual reproduction where the single chromosome replicates and the cell divides into two identical cells.
  • What controls progression through the cell cycle?
    Checkpoints regulated by proteins monitor DNA integrity and spindle formation to control cell cycle progression.
  • What happens if DNA damage is detected at the G1 checkpoint?
    The cell attempts repair; if unsuccessful, it may undergo apoptosis (programmed cell death).
  • How can loss of cell cycle control lead to cancer?
    Disruption of checkpoints allows uncontrolled cell division, leading to tumor formation.
  • What are oncogenes and tumor-suppressor genes?
    Oncogenes promote cell growth when hyperactive; tumor-suppressor genes inhibit growth and cause cancer when inactivated.
  • What is the difference between a benign and malignant tumor?
    Benign tumors grow slowly and remain localized; malignant tumors invade other tissues and can metastasize.
  • What is asexual reproduction?
    Reproduction by a single parent producing genetically identical offspring without gamete fusion.
  • What is sexual reproduction?
    Reproduction involving fusion of gametes from two parents, producing genetically diverse offspring.
  • What is the significance of genetic diversity in sexual reproduction?
    Genetic diversity increases the chance of offspring survival in changing environments.
  • What are homologous chromosomes?
    Pairs of chromosomes similar in length and gene content, one from each parent.
  • What is meiosis and its purpose?
    A type of cell division that reduces chromosome number from diploid to haploid to produce gametes.
  • What occurs during prophase I of meiosis?
    Homologous chromosomes pair (synapsis) and crossing over occurs, increasing genetic variation.
  • What is independent assortment in meiosis?
    Random orientation of chromosome pairs at metaphase I, producing diverse gamete combinations.
  • How does crossing over contribute to genetic variation?
    Exchange of DNA segments between non-sister chromatids creates recombinant chromosomes.
  • What is random fertilization?
    Any sperm can fuse with any egg, increasing genetic variation in offspring.