Lesson Objectives

Why are cells small?

What are the stages of the cell cycle?

What are the stages of interphase?​

Cell Size

• Cells are SMALL!

• Key factor - The ratio of surface area of the cell membrane to the volume inside the cell

• A high ratio = good

  • A lot of surface area and small volume inside

Cell Size

• If cell grows too large, processes slow down

  • Transport of substances (nutrients in/waste out)

  • Cell communication

• Cells will divide before they become too large

  • Maintains small size

  • Creates new cells

Forms of DNA

• Chromosomes

  • Structures in the nucleus that contain of genetic material (DNA)

    • Tightly wrapped up form of DNA

• Chromatin

  • Relaxed, unwrapped form of DNA

• Humans have 46 chromosomes

  • Other organisms have different # of chromosomes

Cell Cycle

There are 3 main stages of the Cell Cycle

​

Stage 1 - Interphase (normal cell activities)

• 3 sub-stages

  • G1 - Gap 1 (cell grows, performs normal functions)

  • S - Synthesis (chromosomes are copied)

  • G2 - Gap 2 (cell prepares to divide)​

Cell Cycle

Stage 2 - Mitosis (nucleus divides)

• 4 sub-stages PMAT

  • Prophase

  • Metaphase

  • Anaphase

  • Telophase​

​

​Stage 3 - Cytokinesis (cytoplasm divides) = 2 new cells

​Cell Cycle - Amoeba Sisters

https://www.youtube.com/watch?v=QVCjdNxJreE​