Cell Division

• What are the two types of cells mentioned in the study material?

  Somatic cells and gametes
• What process do somatic cells undergo?

  Mitosis
• What process do gametes undergo?

  Meiosis
• Why do cells divide instead of just growing larger?

  To avoid stress on DNA and facilitate transport in and out of the cell
• What are the three purposes of cell division?

  To reproduce, repair injuries, and become more efficient
• What are the main differences between plant cells and animal cells?

  • Plant cells lack centrioles, centrosomes, and asters
  • Both have spindle fibers and undergo the same stages of mitosis
• Where are meristematic tissues located in plants?

  In the root tip or the shoot tip
• What happens when cells in the lateral part of the meristem divide?

  Plants grow taller or increase in diameter
• What occurs to chromatin when a cell is about to divide?

  It shortens, condenses, and becomes distorted to form chromosomes
• What are the two arms of a chromosome called?

  The upper arm and the lower arm
• What is a sister chromatid?

  Two chromatids that belong to the same chromosome
• What is the function of the telomere on a chromosome?

  It prevents the tips of chromosomes from joining together
• How many chromosomes do humans have?

  46 chromosomes
• How many chromosomes does a fruit fly have?

  8 chromosomes
• How many chromosomes does a rice plant have?

  12 chromosomes
• How many chromosomes does a dog have?

  39 chromosomes
• What are the two major stages of the cell cycle?

  1. Interphase
  2. Mitosis
• What is the primary activity during interphase?

  The cell grows and organelles double before mitosis
• What occurs during the G1 phase of interphase?

  Cells increase in size and synthesize new proteins and RNA
• What happens during the S phase of interphase?

  DNA replication occurs and chromosomes are doubled
• What is the purpose of the G2 phase of interphase?

  Growth and preparation for mitosis
• What are the stages of mitosis?

  1. Prophase
  2. Metaphase
  3. Anaphase
  4. Telophase
• What happens to chromosomes during prophase?

  Chromosome strands coil tightly, becoming shorter and thicker
• What occurs during metaphase?

  Chromosomes line up across the center of the cell
• What is the role of spindle fibers during metaphase?

  They connect the centromere of each chromosome to the poles of the spindle
• What happens during anaphase?

  Sister chromatids separate and move to opposite poles
• What occurs during telophase?

  Chromosomes begin to disperse into chromatin and the nuclear envelope re-forms
• What is cytokinesis?

  The process that occurs at the same time as telophase, forming two new identical cells
• What is the result of mitosis?

  A single mother cell divides to produce two identical daughter cells
• If a mother cell has 26 chromosomes, how many chromosomes will each daughter cell have after mitosis?

  Each daughter cell will also have 26 chromosomes
• What is meiosis and where does it occur?

  • Meiosis is the process that occurs only in sex cells (sperm and egg cells)
  • It results in daughter cells with different genetic make-up
• What happens during Prophase I of meiosis?

  The chromosomes condense and the nuclear envelope breaks down
• What is synapsis in meiosis?

  The pairing of homologous chromosomes that occurs during Prophase I
• What are homologous chromosomes?

  Pairs of chromosomes, one inherited from each parent, that are similar in shape, size, and genetic content
• What is the cross-over point in meiosis?

  It is where the exchange of genetic material takes place
• What occurs during Metaphase I of meiosis?

  The pair of homologous chromosomes move to the equator of the cell
• What happens during Anaphase I of meiosis?

  The homologous chromosomes separate and move to opposite poles of the cells
• What occurs during Telophase I of meiosis?

  Chromosomes gather at the poles of the cell and the cytoplasm divides
• What is the result after Telophase I of meiosis?

  A single mother cell will form 2 daughter cells with different genetic make-up
• What happens during Prophase II of meiosis?

  A new spindle forms around the chromosomes