The cell cycle is the repeating series of growth and division that produces new cells. It consists of interphase, where the cell grows and DNA is replicated, and mitosis, where the cell divides into two daughter cells each with identical DNA. Chromosomes, made of DNA and proteins, condense during cell division and separate into each new cell, ensuring genetic continuity. The cycle controls cell growth, division, and death through regulated phases.

1. Cell Division

2. The Cell CycleEvery hour, about one billion (109) cells die and one billion cells are made in your body

3. The Cell CycleThrough careful observation, scientists have identified a repeating cycle of events in the life of a cellThis cycle of events is called the cell cycle

4. The Cell Cycle

5. The Cell CycleThe cell cycle has four phases:G1 Phase – Cell growthS Phase – DNA ReplicationG2 Phase – Preparation for MitosisM Phase – MitosisInterphase

6. ChromosomesEvery cell contains chromosomesChromosomes are long pieces of coiled DNA and proteins

7. ChromosomesChromosomes are only visible when the cell is dividing.When the cell is not dividing, the DNA and proteins are spread throughout the cell as chromatin

8. ChromosomesAt the beginning of cell division, the chromosomes condense into visible structuresDude, mitosis starts in five minutes… I can’t believe you’re not condensed yet!

9. Chromosomes

10. ChromosomesBefore cell division can occur, each chromosome is copied so that each chromosome consists of two identical sister chromatidsWhen cells divide, one chromatid goes to each of the new cells

11. The Cell CycleRecall that a cell spends about 90% of its time in interphase

12. G1 Phase – Cell growth

13. S Phase – DNA Replication

14. G2 Phase – Preparation for Mitosis

15. M Phase – MitosisInterphase

16. InterphaseDuring interphase, the cell takes in nutrients, grows and conducts other normal cell functions

17. First Growth Phase (G1)The G1 Phase is a period of growth for the cellDuring this phase, new proteins and organelles are produced

18. Synthesis Phase (S)During the S Phase, the cell makes (synthesizes) an entire copy of the DNA of the cell

19. Second Growth Phase (G2)During the G2 Phase, the cell produces the organelles and structures needed for cell divisionThe G2 Phase is the shortest part of interphase

20. Cell DivisionOnce the cell is ready to divide and make two new identical cells, it enters mitosis (M Phase)During the M Phase, all of the cell’s energy is devoted to the process of cell division

21. MitosisThere are four phases in mitosis:ProphaseMetaphaseAnaphaseTelophase(and Cytokinesis)

22. MitosisAt the end of telophase, two daughter cells are formed, each containing identical genetic information

23. ProphaseDuring prophase, the chromatin (DNA and proteins) that makes up the chromosomes condensesThe DNA has already been replicated, so the chromosomes contain two identical sister chromatids

24. MetaphaseDuring metaphase, the chromosomes line up at the center of the cellSpindle fibers extend from the poles of the cell and attach to the centromeres of each chromosome

25. AnaphaseDuring anaphase, the sister chromatids separate at the centromereThe separated chromosomes are pulled to opposite ends of the cell

26. Telophase & CytokinesisDuring telophase, the cell divides the cytoplasm into two portionsThe process of splitting the cytoplasm is known as cytokinesis

27. Telophase & Cytokinesis

28. Telophase & Cytokinesis

29. Telophase & Cytokinesis

30. Interphase

31. Cell DeathThe cell cycle regulates how long a cell livesSometimes cells die because they have suffered injury or damage that cannot be repaired

32. ApoptosisA cell also dies when it is no longer needed or useful to the organismThis regulated or controlled cell death is called apoptosisThe cell on the bottom is healthy and normal, while cell on the top is undergoing apoptosis.