The Cell Cycle

The Life of a Cell  Cells pass through different stages in their lives  These stages = Cell Cycle  Begins when cell forms, and ends when cell divides  Before division, has to copy its DNA

Prokaryotic or Eukaryotic?  Prokaryotic cells: simple! No membrane covered organelles, small circle of DNA.  Split into 2 parts = Binary fission  Each new cells contains 1 copy of the DNA

Eukaryotic cells  More complex; more DNA  DNA is in chromosome pairs = homologous chromosomes  Humans have 23 pairs, or 46 total

What do chromosome pairs look like?

The Cell Cycle

Phases of the Cell Cycle  IPMAT  Interphase: Cell grows (G1 and G2), and copies its DNA (S = synthesis)

A Cell’s Life  Interphase  Mitosis Prophase Metaphase Anaphase Telophase

Phases of Mitosis Prophase: PREPARATION phase; DNA twists into chromosomes, nuclear membrane breaks down Metaphase: Chromosomes MEET in the MIDDLE of the cell Anaphase: Chromosomes separate and move APART Telophase: The cell TEARS into two

Prophase  Chromosomes starting to form, nuclear membrane starts to break apart

Metaphase Hint: Think of this as the meta or (middle) phase where chromosomes line up in the middle of the cell.

Anaphase Hint: This is were the 2 sisters Ana and Ana are pulled apart to different ends of the cell…so sad.

Telophase Hint: Now the sisters are far apart and starting separate lives. They have to call each other by TELOphone.

Cytokinesis At the end of Telophase the cell membrane pinches into two identical cells. Animal CellPlant Cell In plant cells a cell plate forms and later becomes the cell membrane.

QUIZ 1. The cell cycle is the cell’s what? Life cycle 2. What two main stages make up the cell cycle? Interphase and Mitosis 3. What happens during Interphase? During interphase the cell grows and copies its DNA. 4. Mitosis is all about a cell doing what? Mitosis is all about cells dividing in half and making sure each new cell has the exact same DNA as the parent cell.

QUIZ CONT. 5. In what phase of Mitosis do the chromosomes line up in the center of the cell? Metaphase 5. In what phase of Mitosis do the spindle fibers first pull the chromosomes apart? Anaphase 5. In what phase of the Mitosis do chromosomes start to form? Prophase