Transcript sc10u9lesson7

 One cell divides into two new cells with identical
genetic information as the parent cell.
Nucleus:
 Nuclear envelope: a double membrane surrounding
the nucleus.
 Nucleolus: produces ribosomes.
 Deoxyribonucleic acid (DNA):
• DNA exists in long fibres called chromatin.
• Each fibre makes up a chromosome.
• On a chromosome are genes that carry
information for the cell to function and reproduce.
The Cell Cycle:
1. Interphase:
• Longest part of a cell’s life cycle.
• Growing and preparing for reproduction.
• DNA is in fibrous chromatin form (not visible).
• DNA duplicates.
2. Prophase:
• Duplicated chromatin coil to form chromosome
(consisting of two sister chromatids)
• Nuclear membrane begins to break down.
• Spindle fibres begin to appear from centromeres
as they move to opposite sides of the cell.
• Centromere joins each pair of sister chromatids to
a spindle fibre.
3. Metaphase:
• Chromosomes line up along equator of cell.
• Spindle fibres are getting ready to pull the sister
chromatids away from each other.
4. Anaphase:
• Sister chromatids separate from the centromere
and are pulled to opposite poles of the cell.
• Each sister chromatid is now a chromosome.
5. Telophase:
• Spindle fibres disassemble.
• Nuclear envelope reforms around each group of
chromosomes.
6. Cytokinesis:
• Splitting of the cytoplasm.
• In animal cells a new cell membrane forms (in
plant cells, a cell wall forms) producing two
identical daughter cells.
Overview: Cell Life Cycle
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Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
Mitosis: division of the nucleus