Mitosis & Meiosis
How cell division works
Mitosis
- The series of event that cells go through as they grow/divide
- Process:
- Grows (Interphase/G1/S/G2)
- Prepares for division (Mitosis/Prophase/Metaphase/Anaphase/Telophase)
- Cytoplasm divides to form two daughter cells
- Interphase
- Longest phase
- Cell appears to be at rest
- G1 phase
- Period where cells do most of growing
- S phase
- DNA is copied
- G2 phase
- Shortest phase
- Organelles needed for cell division are produced
- At the end of this phase cell gets ready to divide/start M phase
- M phase
- Mitosis (preparation) and cytokinesis (cell division)
- Cell division has two stages in eukaryotes
- Stage 1: Mitosis
- Prophase
- Nuclear membrane breaks down
- Nucleolus disappears
- Chromatin condenses into chromosones
- Centrioles separate and a spindle begins to form
- Metaphase
- Chromosomes line up across the middle
- Each chromosome connects to a spindle fiber at its centromere
- Anaphase
- Sister chromatids separate into individual chromosomes and move to opposite ends
- Telophase
- Nucleolus reappears
- Chromosomes gather at the opposite ends
- They lose their shape
- New nuclear envelopes begin to form
- Stage 2: Cytokinesis
- Cytoplasm pinched in half
- Each daughter now has all chromosomes (diploid-2n cells)
LINK TO MORE INFORMATION
Onion Cell Mitosis