All cells arise from other cells

• What is the first stage of the cell cycle in eukaryotic cells?

  Interphase
• What occurs during the S phase of interphase?

  DNA replicates semi-conservatively
• What do two chromatids represent?

  Identical copies joined at a centromere
• What happens during G1 and G2 phases of interphase?

  Organelles increase and protein synthesis occurs

  
• What is the purpose of mitosis?

  To produce two nuclei with identical DNA
• What occurs during cytokinesis?

  Cytoplasm and cell membrane divide
• What is the result of cytokinesis?

  Two genetically identical daughter cells
• What happens to chromosomes during prophase?

  Chromosomes condense and become visible
• What forms the spindle network during prophase?

  Centrioles move to opposite poles
• How do spindle fibres behave during metaphase?

  They attach to chromosomes by their centromeres
• What is the key event in anaphase?

  Centromere divides and chromatids are pulled apart
• What happens to chromosomes during telophase?

  Chromosomes uncoil and nuclear envelopes reform
• Why do some eukaryotic cells not undergo the cell cycle?

  Not all cells retain the ability to divide
• What is the importance of mitosis for multicellular organisms?

  It allows growth and tissue repair
• What leads to the formation of tumors?

  Uncontrolled cell division due to mutations
• What distinguishes malignant tumors from benign tumors?

  Malignant tumors can spread (metastasis)
• How do some cancer treatments disrupt cell division?

  They disrupt spindle fibre activity
• What is binary fission?

  A method of prokaryotic cell replication

  
• What are the steps of binary fission?

  Replication of DNA and division of cytoplasm

  
• How do viruses replicate?

  They inject nucleic acid into host cells
• What is the role of attachment proteins in viral replication?

  They attach to receptors on host cells
• What is a mitotic index?

  Proportion of cells undergoing mitosis
• How can a reliable mitotic index be determined?

  Count cells in mitosis and total cells
• How do you calculate the time cells spend in a certain phase of mitosis?

  Identify proportion of cells in that phase
• What are the stages of the cell cycle in eukaryotic cells?

  1. Interphase

  • S phase: DNA replication
  • G1/G2: Organelles increase, protein synthesis

  1. Mitosis

  • Nucleus divides, producing two nuclei

  1. Cytokinesis

  • Cytoplasm and membrane divide, forming daughter cells

  
• What are the stages of mitosis and their characteristics?

  1. Prophase: Chromosomes condense, nuclear envelope breaks down
  2. Metaphase: Chromosomes align at the equator
  3. Anaphase: Chromatids pulled to opposite poles
  4. Telophase: Chromosomes uncoil, nuclear envelopes reform

  
• What are the common mistakes regarding mitosis and cell division?

  • Mitosis repairs cells, not the cells themselves
  • DNA replication occurs in interphase, not mitosis
  • Chromosomes and chromatids are not the same
  • Centromeres join chromatids, centrioles form spindle
  • Cytokinesis may not occur in all cells
• What is the procedure for preparing squashes of cells from plant root tips?

  1. Cut thin slice of root tip
  2. Soak in hydrochloric acid, rinse
  3. Stain for DNA
  4. Lower coverslip without trapping air
  5. Squash gently to spread cells
• What are the rules for scientific drawing?

  • Look similar to specimen
  • No sketching or shading
  • Include magnification scale
  • Label with straight, uncrossed lines
• How to set up and use an optical microscope?

  1. Clip slide onto stage, turn on light
  2. Select lowest power lens
  3. Use coarse focus to bring stage close
  4. Adjust fine focus for clarity
  5. Swap to higher power lens, refocus