Cell Cycle Notes

The Cell Cycle is

• The cycle of a cell's growth and division

• ​Three main stages

  • ​Interphase - longest

  • ​Mitosis

  • ​Cytokinesis - shortest

​Interphase: Growth phase

• ​the cell grows in size, performs normal functions, copies its DNA

• ​Three parts

  • ​G1: ​cell growth

    • ​cell functions normally

  • S​: DNA replication

    • Chromatin is split to allows replication

    • Chromatin is the relaxed from of DNA in the nucleus

      • phase that DNA spends most time in because it allows proteins access to information stored in DNA

  • G2

    • cell prepares for division

    • duplicates organelles​

​Mitosis: division of the nucleus

• ​Four phases

  • ​Prophase

  • ​Metaphase

  • ​Anaphase

  • ​Telophase

​Cytokinesis

• ​Divison of the cytoplasm

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Two daughter cells are produced

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​Start the cycle over again at interphase

PMAT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!​

• ​The longest phase of mitosis

• ​Chromatin condenses to form chromosomes

• ​Sister chromatids attach together near the center of the chromosomes by a centromere

  • ​Sister chromatids are IDENTICAL copies of DNA

• ​Nuclear membrane disappears

• ​Spindle fibers form

• ​Centrioles migrate to opposite ends of the cell for spindle attachment

• ​Sister chromatids attach to spindle fibers

• ​Chromosomes are lined up at the center of the cell (equator of the cell)

• ​Shortest phase of mitosis

• ​The centromere splits and the sister chromatids are pulled by the spindle to opposite ends of the cell

• Last part of mitosis

• ​Chromosomes arrive at opposite ends of cells

• ​Chromosomes unwind

• ​Nuclear membrane reforms

• ​Nucleoli reappear

• ​Spindle apparatus is broken down

• Division of the cytoplasm

​Animal Cells

• ​Microtubules constrict, or pinch, the cytoplasm in half

Plant Cells​

• ​Cell plate forms in between the new nuclei

• ​Cell walss form on either side of the cell plate, dividing the cell into two new daughter cells

​Results in two IDENTICAL daughter cells

​Binary Fission

1. ​DNA is replicated

2. ​DNA and cytoplasm split

3. ​Two new cells produced