cell cycle + mitosis

• What is the basic unit of life?

  Cells
• Why must cells be small?

  To function as independent living organisms through processes like diffusion and osmosis
• What processes require a large amount of surface area in cells?

  Diffusion and osmosis
• What is the origin of all cells?

  • All cells are derived from preexisting cells
• How does cell division occur in prokaryotes?

  Through binary fission
• What are the four stages of the cell life cycle in eukaryotic cells?

  1. G1 (Gap 1): Everything except chromosomes is duplicated
  2. S phase: DNA is copied
  3. G2 phase (Gap 2): Chromosomes are checked before mitosis
  4. M phase: Mitosis
• Why do cells divide at different rates?

  Because some cells need to be replenished more often than others
• What limits cell size?

  If cells are too small, they cannot fit all necessary organelles
• What happens if a cell gets too large?

  There will be too little surface area for diffusion to take place
• What is interphase in the cell cycle?

  • Everything besides mitosis
• What is the G0 phase in the cell cycle?

  A state in which the cell is no longer dividing
• What are the steps of mitosis?

  1. Prophase: DNA packs into chromosomes, centrioles appear, nuclear envelope disappears
  2. Metaphase: Chromosomes line up in the middle, spindle fibers attach
  3. Anaphase: Chromatids separate at the centromere and move towards poles
  4. Telophase: Chromosomes unwind, nuclear envelope forms
  5. Cytokinesis: Cytoplasm and organelles duplicate, cleavage furrow appears
• What is the first step of mitosis?

  Prophase
• What occurs during prophase?

  DNA is packed into chromosomes, centrioles appear, and the nuclear envelope disappears
• What is the second phase of mitosis?

  Metaphase
• What happens during metaphase?

  Chromosomes line up in the middle of the cell and spindle fibers attach to them
• What is the third phase of mitosis?

  Anaphase
• What occurs during anaphase?

  The chromatids of each chromosome separate at the centromere and move towards the poles
• What is the fourth phase of mitosis?

  Telophase
• What happens during telophase?

  Chromosomes reach the poles, spindle fibers break apart, and the nuclear envelope forms around the DNA
• What is cytokinesis?

  The process that finalizes cell division
• What marks the beginning of cytokinesis?

  The appearance of the cleavage furrow
• What is the cleavage furrow?

  The area of the cell membrane that pinches in and eventually separates the cell
• Why is mitosis important?

  • Cellular reproduction is essential to all living things
  • Nonliving things like viruses also need to reproduce
  • Regulated cell procedures ensure every cell receives DNA and organelles
  • Prevents cell death or disease