Topic 2- Cells and control

• What is the cell cycle?

  A series of events in a cell
• How is the cell cycle described?

  As the lifecycle of a cell
• What are the three stages of the cell cycle?

  Interphase, mitosis, cytokinesis
• What is interphase?

  The longest stage of the cell cycle
• What occurs during interphase?

  Cell growth, organelle synthesis, DNA replication
• What does DNA replication involve?

  Double helix unzips, bases align, pairs join
• What is a chromosome?

  A linear DNA molecule tightly coiled
• What happens to chromosomes during DNA replication?

  The DNA in each chromatid is replicated
• What is mitosis?


  A form of cell division producing two diploid cells
• Why is mitosis important in organisms?

  Asexual reproduction, growth, repair, replacement
• What are the four stages of mitosis?

  Prophase, metaphase, anaphase, telophase
• What happens during prophase?

  DNA condenses, chromosomes become visible
• What happens during metaphase?

  Chromosomes line up along the cell equator
• What happens during anaphase?

  Spindle fibres pull chromatids to opposite poles
• What happens during telophase?

  Nucleus divides, new membrane forms around chromosomes
• What does cytokinesis involve?

  Division of cell membrane and cytoplasm
• If a cell divides by mitosis every 2 minutes, how many cells are present after 10 minutes?

  32 cells
• What is cancer?

  Non-communicable disease with uncontrolled cell division
• What results from uncontrolled cell division in cancer?

  Formation of a primary tumour
• What are percentile charts used for?

  To monitor growth and compare measurements
• What does the 95th percentile mean?

  95% of measurements are below this value
• What can doctors determine from percentile charts?


  Growth patterns: slower, faster, or abnormal
• How does growth occur in animals?

  Cell division occurs in all body cells
• How does growth in adults differ from younger animals?

  Slower rate as growth stops
• What happens to most cells during differentiation?

  They become specialized early on
• Where does cell division occur in plants?

  Only in meristematic tissue
• How does cell division rate change in plants?

  Remains the same throughout a plant's life
• What can meristematic stem cells do?

  Differentiate into any cell type for life
• What occurs during cell elongation in plants?

  Cells expand and enlarge for growth
• What are stem cells?

  Unspecialised cells capable of differentiation
• What is meant by differentiation?

  The process by which stem cells become specialized
• What is the process by which most cells become specialized?

  Cell differentiation
• What do adult stem cells retain the ability to do?

  Differentiate into specialized cells
• Where does cell division occur in plants?

  Meristematic tissue
• How does the rate of cell division change throughout a plant's life?

  It remains the same
• What can meristematic stem cells differentiate into?

  Any cell type for the plant's life
• What occurs during cell elongation in plants?

  Cells expand and enlarge
• What does differentiation mean in the context of stem cells?

  Becoming specialized with a specific function
• Why is cell differentiation important?

  It forms specialized tissues with specific functions
• What are embryonic stem cells?

  Stem cells in early embryos capable of differentiation