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Cell Reproduction
• Interphase– Cell growth, DNA synthesis, Growth and
Preparation
• Mitosis (Division)– dividing the nucleus into two daughter nuclei
• Cytokinesis (Division)– separating the organelles and the cytoplasm
Mitosis
• Mitosis is a continuous process that can be observed in four stages: – Prophase– Metaphase – Anaphase– Telophase
Prophase 1• Chromosomes begin to condense• The nuclear membrane breaks down. • Spindle which is made up of several spindle
fibers form. – run at a right angle to the cell’s equator.
• An organelle called the centrosome helps assemble the spindle. – animal cells includes a pair of centrioles– centrosomes move to opposite poles of the cell
Metaphase• Chromosomes are packaged into their most
condensed form.
• Nuclear membrane is fully dissolved
• Chromosomes move to the center of the cell
• Spindle fibers form a link between the poles and the centromere of each chromosome.
Anaphase• Spindle fibers shorten
• Sister chromatids move toward opposite poles as the spindle fibers shorten.
• Each pole now has a full set of chromosomes.
Telophase• A nuclear envelope forms around the
chromosomes at each pole of the cell.
• Chromosomes now uncoil.
• The spindle dissolves.
• Mitosis is complete.
Cytokinesis• The cytoplasm is separated
• Two daughter cells are formed – Have half of the parent’s cytoplasm and organelles– Genetically identical diploid cells
• After cytokinesis, each cell enters the G1 stage of interphase.
Summary• The life of a eukaryotic cell cycles through;
– Growth, DNA replication– preparation for cell division – division of the nucleus and cytoplasm
• Mitosis is a continuous process that includes four stages: – Prophase– Metaphase – Anaphase– Telophase
• Cytokinesis– the cell membrane grows into the center of the cell and divides
it into two daughter cells– each daughter cell has about half of the parent’s cytoplasm and
organelles