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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 • • • • • • Interphase Prophase Metaphase Anaphase Telophase Cytokinesis Mitosis: division of the nucleus