Cell Division in Prokaryotes and Eukaryotes Cell Division

Cell Division in Prokaryotes and Eukaryotes

Cell Division in Prokaryotes • Prokaryotes reproduce through binary fission. • 3 steps: – Cell duplicates its chromosome. – Cell doubles in size. – DNA is divided and 2 new cells are formed. • Two new cells are identical to one another.

Cell Division in Eukaryotes • All eukaryotes go through the cell cycle. – Cell cycle – different stages of life for cells • Made up of 2 parts: – Interphase – time between divisions • G 1 – cell grows to its mature size • S (synthesis) – chromosomes are copied • G 2 – cell prepares for division – M phase – cell division • Mitosis – chromosomes in nucleus divide • Cytokinesis – the rest of the cell divides • Cells can leave the cell cycle. – Some cells stop dividing (ex: nerve cells) – These cells are said to be in G 0

Cell Division in Eukaryotes • Cell division happens during the M phase of cell cycle • Made of 2 parts: – Mitosis – nucleus divides • • Prophase Metaphase Anaphase Telophase – Cytokinesis – cytoplasm divides

Prophase • Chromsomes coil up and condense – 1 st time chromosomes are visible • Nuclear membrane breaks down • Centrosomes appear and move to opposite ends of the cell • Spindle fibers attach to each chromosome – Attach at the centromere

Metaphase • Meta = middle • Spindle fibers move chromosomes • Chromosomes line up along the middle of the cell

Anaphase • Spindle fibers shorten and move the chromosomes across the cell • Chromosomes separate, and chromatids are pulled apart • Chromatids move to opposite ends of the cell

Telophase • Chromosomes reach ends of the cell • Spindle fibers detach and disassemble • Nuclear membrane reforms around each set of chromosomes • Nucleolus reforms • One large cell with two identical nuclei • Cytokinesis happens next – Splits the rest of the cell – Different in plants and animals

Cytokinesis in Animal Cells • Cell membrane pinches in forming a cleavage furrow until cells are separated. • The cytoskeleton causes this to happen.

Cytokinesis in Plants • Vesicles from Golgi fuse together forming a membrane-bound cell wall called a cell plate. • Eventually it grows to separate the cells.

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