Chapter 10: Cell Growth and Division

  • Why do cells need to divide?- Cells need to divide because as cells grow larger it demands more on the cell's DNA, it is harder to move materials across the cell membrane, and because the cell's volume grows faster than the cell's surface area.
  • What is a chromosome? - Chromosomes are packages of genetic information that is bundled together.

  • The parts of a chromosome include the

  • Centromere: holds the 2 chromatids together
  • Gene: segment of DNA that codes for a trait
  • Chromatids: identical copies

  • The events of the cell cycle include:

  • G1: growth and normal metabolic roles
  • S phase: DNA replication
  • G2: growth and preparation for mitosis
  • M phase: mitosis begins (prophase, metaphase, anaphase, and telophase)
  • Cytokinesis

The Cell Cycle

  • The steps of Mitosis include:
  • Prophase- Genetic material inside the nucleus condenses and the duplicated chromosomes become visible. Outside of the nucleus the spindle fibers begin to form. The fibers are attached to the centrioles that are moving to the poles of the cell
  • Metaphase- The centromeres of the duplicated chromosomes line up across the center of the cell. The spindle fibers connect the centromere of each chromosome to the two poles of the spindle
  • Anaphase- The chromosomes separate and move along the spindle fibers to the opposite ends of the cell
  • Telophase- The chromosomes, which were distinct and condensed, begin to spread out into a tangle of chromatin
The process of cytokinesis

  • During cytokinesis in animal cells, the membrane is drawn inward until the cytoplasm is pinched into two equal parts. Each part contains its own nucleus and cytoplasmic organelles
  • During cytokinesis in plant cells, a structure known as the cell plate forms halfway between the divided nuclei and the cell forms in between the daughter cells, thus, completing the cell cycle

  • The difference between the processes of cytokinesis and mitosis are that mitosis is the splitting of the nucleus. And cytokinesis is the splitting of the cytoplasm.