Skip to main content
Back

Cellular Reproduction and Cell Division

Control buttons has been changed to "navigation" mode.
1/29
  • What is cell division?

    Cell division is the splitting of one parent cell into two genetically identical daughter cells.

  • Define asexual reproduction.

    Asexual reproduction is cell division that results in the reproduction of a whole organism, producing genetically identical clones.

  • What is sexual reproduction?

    Sexual reproduction requires the fusion of gametes (egg and sperm cells) and produces offspring genetically different from parents.

  • What is binary fission?

    Binary fission is the process by which prokaryotes divide, involving duplication and separation of a single circular DNA molecule.

  • What are the two main types of eukaryotic cell division?

    Mitosis for growth and maintenance; Meiosis for producing gametes used in sexual reproduction.

  • What is chromatin?

    Chromatin is the diffuse mass of DNA and proteins in the nucleus that coils into chromosomes when the cell prepares to divide.

  • Define sister chromatids and centromere.

    Sister chromatids are two identical copies of a chromosome attached at the centromere.

  • What are the two main stages of the cell cycle?

    Interphase (growth and DNA replication) and Mitotic phase (mitosis and cytokinesis).

  • Describe the phases of interphase.

    G1: cell growth; S: DNA synthesis; G2: preparation for mitosis.

  • What occurs during mitosis?

    Mitosis divides the nucleus into two genetically identical nuclei through prophase, prometaphase, metaphase, anaphase, and telophase.

  • What happens in prophase?

    Chromatin coils into chromosomes; mitotic spindle forms; centrosomes begin to move apart.

  • What occurs during prometaphase?

    Nuclear envelope breaks down; spindle microtubules attach to kinetochores on chromosomes.

  • Describe metaphase in mitosis.

    Chromosomes align at the metaphase plate; spindle fibers attach to kinetochores from opposite poles.

  • What happens during anaphase?

    Sister chromatids separate and move to opposite poles powered by motor proteins and ATP.

  • What occurs in telophase?

    Chromosomes arrive at poles; nuclear envelopes reform; chromatin decondenses; mitotic spindle disappears.

  • Define cytokinesis and how it differs in animal and plant cells.

    Cytokinesis divides the cytoplasm. In animal cells, a cleavage furrow forms; in plant cells, a cell plate forms to create new cell walls.

  • What is anchorage dependence?

    Cells must be attached to a solid surface to divide, a property of most animal cells.

  • Explain density-dependent inhibition.

    Crowded cells stop dividing when they touch each other, preventing overgrowth.

  • What is a tumor?

    A mass of abnormally growing cells; benign tumors stay localized, malignant tumors can spread (metastasize).

  • What is the difference between somatic cells and gametes?

    Somatic cells are body cells with diploid chromosome number; gametes are haploid reproductive cells.

  • Define homologous chromosomes.

    Pairs of chromosomes matching in length, centromere position, and gene loci, one from each parent.

  • What is the difference between diploid and haploid cells?

    Diploid (2n) cells have two sets of chromosomes; haploid (1n) cells have one set, as in gametes.

  • What is crossing over?

    Exchange of chromosome segments between non-sister chromatids during prophase I of meiosis, increasing genetic variation.

  • What is nondisjunction?

    Failure of chromosome pairs or sister chromatids to separate properly during meiosis, leading to abnormal gametes.

  • What is a karyotype?

    An ordered display of an individual's chromosomes arranged in pairs, used to detect abnormalities.

  • What causes Down syndrome?

    Trisomy 21: presence of three copies of chromosome 21, leading to developmental and physical effects.

  • Name four types of chromosomal alterations.

    Deletion, duplication, inversion, and translocation, which can cause birth defects or cancer.

  • What is independent assortment?

    Random orientation of homologous chromosome pairs during metaphase I of meiosis, contributing to genetic diversity.

  • How many possible chromosome combinations can human gametes produce?

    Approximately 8.4 million, calculated as \(2^{23}\).