1. Liceo Scientifico P.P. Pasolini Potenza Biology course The Cell Cycle Teacher Anna Massenzio

2. The complex life of a cell is divided into five phases: Gap1 DNA synthesis Gap2 Cell division Cytokinesis Interphase

3. During the interphase the cell increases in size. The DNA of the chromosomes is replicated and the centrosome is duplicated. 90% of the cell cycle concerns the interphase, which consists of three moments: 1.G 1 - when new organelles are made and the cell carries out its various functions 2. S - when faithful copies of DNA cell are made 3. G 2 - when the cell prepares for further cell division, condensing DNA into chromosomes

4. Cell division can be by mitosis or meiosis depending on whether the chromosomes number is to be unchanged or halved

5. Mitosis is a replication-division which produces two daughters cells, each with the same number of chromosomes as the parent cell. Diploid cell (2n): two sets of chromosomes Haploid cell (n): one set of chromosomes

6. Functions of mitosis: Amoeba in mitosis growth of an organism repair of damaged cells asexual reproduction

7. Mitosis and Cancer If cells divide when new ones are not nedeed, they form a mass of excess tissue, called tumor. benign tumor Some tumor cells stay together and do not tend to spread malignant tumor/cancer Tumor cells invade nearby organs or travel to new body sites

8. Meiosis is a reduction-division which produces four daughter cells, each with half the number of chromosomes of the original parent cell. It halves the chromosome number, producing haploid cells from diploid cells. 2n n n n n haploid cells Diploid cell

9. Meiosis produces sex cells. It maintains the original chromosome number within the population: haploid cells, or gametes, unite in fertilization to restore the original diploid number.

10. Cytokinesis, or division of the cytoplasm, occurs when the cell separates into daughter cells. It initiates during the late stage of mitosis, and sometimes meiosis, splitting a binucleate cell into two, to ensure that the chromosome number is mantained from one generation to the next one. direction into two

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