Cell & Nuclear Division

• What is the process called where the nucleus divides into two genetically identical daughter nuclei?

  Mitosis
• Why is mitosis important for cells?

  It ensures that each new cell receives an exact copy of the genetic material from the parent cell.
• What are the two main components of the cell cycle besides mitosis?

  Interphase and cytokinesis
• What happens to chromosomes during mitosis?

  They undergo condensation, becoming more compact and visible under a microscope.
• How can you visualize the condensation of chromosomes during mitosis?

  By comparing it to twisting a long, tangled string tightly to make it shorter and thicker.
• What is cytokinesis?

  The division of the cytoplasm that occurs after mitosis.
• How does cytokinesis differ between plant and animal cells?

  In animal cells, a contractile ring pinches the cell, while in plant cells, a cell plate forms to create a new cell wall.
• What occurs during the G1 phase of interphase?

  Cell growth and preparation for DNA synthesis.
• What happens during the S phase of interphase?

  DNA replication occurs.
• What is the G2 phase of interphase responsible for?

  Further growth and preparation for mitosis.
• What common mistake do students make regarding interphase?

  They believe it is a "resting" phase.
• What are cyclins?

  A family of proteins that control the cell cycle.
• How do cyclins function in the cell cycle?

  They act as regulatory subunits of cyclin-dependent kinases (CDKs) to drive the cell through various stages.
• What factors can lead to cancer in relation to cell division?

  Mutagens, oncogenes, and metastasis.
• What is metastasis?

  The spread of cancer cells from the primary tumor to other parts of the body.
• Why is understanding cell division processes important for cancer treatment?

  It is crucial for developing cancer treatments and prevention strategies.
• What are the four main phases of mitosis?

  • Prophase
  • Metaphase
  • Anaphase
  • Telophase
• What occurs during prophase of mitosis?

  Chromosomes condense, the nuclear envelope begins to break down, and centrosomes move to opposite poles.
• What happens during metaphase of mitosis?

  Chromosomes align at the cell's equator and spindle fibers attach to the centromeres.
• What is the key event during anaphase of mitosis?

  Sister chromatids separate and move to opposite poles of the cell.
• What occurs during telophase of mitosis?

  Chromosomes decondense, the nuclear envelope reforms, and cytokinesis begins.
• What mnemonic can help remember the order of mitotic phases?

  PMAT (Prophase, Metaphase, Anaphase, Telophase)
• What features should students look for to identify mitotic phases under a microscope?

  Chromosome condensation, position of chromosomes, presence of nuclear envelope, and separation of sister chromatids.
• What is the mitotic index?

  A measure of cell division calculated as the ratio of cells in mitosis to the total number of cells.
• If 25 out of 500 cells are in mitosis, what is the mitotic index?

  $\text{Mitotic Index} =$$\frac{25}{500} =$$0.05$
• What is the difference between sister chromatids and homologous chromosomes?

  Sister chromatids are identical copies of the same chromosome, while homologous chromosomes are pairs from each parent carrying genes for the same traits.
• What terminology should be used after anaphase when sister chromatids separate?

  They should be referred to as chromosomes.
• What are the implications of understanding cell and nuclear division in biology?

  • Fundamental to biology
  • Important in genetics
  • Relevant in cancer research
  • Useful in biotechnology