Definition: the complete series of events from one cell division to the next — compare - g1 phase, g2 phase, m phase, s-phase Source:"Cell Cycle." Merriam-Webster.com. Merriam-Webster, n.d. Web. 7 Jan. 2018.
Key Terms:
Interphase: Longest phase of cell cycle, includes G1, S, G2 and M phases.
Chromosome: Structure in many living organism which contain and carry genetic information
Mitosis: Process in the cell cycle in which chromosomes are divided into new nuclei.
DNA Replication: The process by which DNA, which carries genetic instructions, is duplicated from the original strand of DNA.
Sister Chromatid: Identical copies of a chromosome joined by a centromere.
Cell Cycle Summary
The Cell cycle describes each phase of a cell’s life. There are approximately four stages to a cells life. Each separated into phases. Beginning with G1 phase, S phase, G2 phase, and M phase. Interphase is the longest phase, composing the first three stages of the cell cycle. During G1 phase the cell grows and duplicates it substances besides chromosomes. S-phase which is the most vital stage in interphase, the cell copies its it’s DNA,through, DNA replication and in G2 phase the cell resumes its growth and prepares for M-phase by manufacturing proteins.
Cell Cycle Infograph
Mitosis is the stage when chromosomes are duplicated and the cell is fully developed and prepared to be divided into two daughter cells. During S-phase sister chromatids were created from the process of DNA replication in which the complementary and existing strand are together and paired at a centromere. The phases of Mitosis include Prophase, Metaphase, Anaphase, and Telophase.
During prophase the nucleus surrounding the pairs of chromatids is reduced and eventually completely breaks down, while the centrioles in the cell move towards the poles. Next, metaphase, the centrioles manufacture spindles which become tethered to the centromeres of the sister chromatids which aligned themselves up the middle of the cell. Then Anaphase, the shortening spindles pull the sister chromatids apart moving the material to opposite walls of the cell. Finally during telophase the new membranes have formed and surround the separated chromosomes and they extend, nearly ready for separation.
Mitosis Infograph
CYTOkinesis
Cytokinesis Infograph
Usually during Telophase the process of Cytokinesis has already been initiated. Cytokinesis can simply be described as the cleaving of the cell. The cell is divided at the contractile ring which provides the energy to separate the cell into two, genetically identical daughter cells.
Cytokinesis is completed when the cell is separated completely, into two daughter cells. If these daughter cells are average they should have 23 sets of chromosomes. They are reproduced by going through the cell cycle individually until trillions upon trillions of cells are being continually created through the organism’s life.
REview-Quiz
1. Through which stage does the DNA duplicate? a) M-phase b) G1 phase c) S-Phase d) Telophase
2. Put this diagram of Mitosis into the correct order;
(ignore first depiction)
a) Prophase, Metaphase, Anaphase, Telophase, Cytokinesis, b) Anaphase, prophase, telophase, cytokinesis, metaphase c) Cytokinesis, anaphase, metaphase, telophase, prophase d) Telophase, cytokinesis, anaphase, prophase, metaphase
3. How many chromosome pairs belong in an average pair of daughter cell after Cytokinesis?
a) 46 b) 92 c) 21 d) 23
4. Give a brief summary in at least 4 sentences how Mitosis works?
5. How do daughter cells reproduce after Cytokinesis?