1) How are the different stages of the cell cycle distinguished?
The cell cycle is used by eukaryotic cells. The cell cycle is made up of primarily two main phases, interphase and mitosis, each having different stages. Interphase is what makes up the majority of the cell cycle and is the phase which the cell is “living and doing its normal functions.” During interphase the cell is perform its normal processes in the cell and preparing to divide. The first stage in interphase is g1, standing for growth. In g1 the cell grows rapidly, it also makes proteins and RNA. The cell then moves to the second stage in the interphase process called s for synthesis. During this time the cell stops growing and makes DNA copies through a process of DNA replication. Now each chromosome consists of two sister chromatids. In the G2 stage the cell makes final preparations to divide. It checks the duplicated chromosomes and might make additional proteins or organelles, anything that insures the cell is ready to divide. Cells that stop dividing or leave the cell cycle stay at the stage G0 (zero). This may be a permanent or temporary resting period. Regulatory proteins controls the cell cycle. These proteins send out signals to tell the cell when to stop or delay the next phase of the cycle.
The cell cycle is used by eukaryotic cells. The cell cycle is made up of primarily two main phases, interphase and mitosis, each having different stages. Interphase is what makes up the majority of the cell cycle and is the phase which the cell is “living and doing its normal functions.” During interphase the cell is perform its normal processes in the cell and preparing to divide. The first stage in interphase is g1, standing for growth. In g1 the cell grows rapidly, it also makes proteins and RNA. The cell then moves to the second stage in the interphase process called s for synthesis. During this time the cell stops growing and makes DNA copies through a process of DNA replication. Now each chromosome consists of two sister chromatids. In the G2 stage the cell makes final preparations to divide. It checks the duplicated chromosomes and might make additional proteins or organelles, anything that insures the cell is ready to divide. Cells that stop dividing or leave the cell cycle stay at the stage G0 (zero). This may be a permanent or temporary resting period. Regulatory proteins controls the cell cycle. These proteins send out signals to tell the cell when to stop or delay the next phase of the cycle.
A coiled structure made up of DNA and proteins is called chromosomes. “Chromosomes are the form of genetic material of a cell during cell division.” When the DNA is not coiled into chromosomes, and is instead in a form of a messy matter, like when you undo a ball of yarn and it bunches together, that is called chromatin. When the DNA is condensed and coils, creating a X-shaped form of chromosomes that means the DNA has be copied. That X-shaped form of chromosomes, is made up of two chromosomes, called sister chromatids. Where they attach to one another is called the centromere.
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Once the cell is ready to divide it moves into the phase known as mitosis. The first stage or part of mitosis is prophase. Prophase is the longest phase and during this phase the chromatin condenses into chromosomes. The nucleus disappears and the centrioles move, spindles , consisting of fiber made of microtubes, start to form. It then moves to metaphase, during this stage/phase the chromosomes align in the middle or center of cell. The spindle fibers attach to each pair of sister chromatids. During anaphase the sister chromatids begain to separated and the centromeres divide. The spindle fibers separate the chromatids by moving towards opposite poles, shorting the spindle fiber, in a reeling fashion. This way each pole has its own set of chromosome. In telophase, the “ cell continues to elongate” and the chromosomes begin to uncoil and form back into chromatin. A new nuclear membrane forms and a nucleoli reappears.
Cytokines is the final stage of the cell cycle and comes after mitosis. It is the final stage in both eukaryotic and prokaryotic cells. During this the cytoplasm splits into two and the cell divides. This process can be different between plant and animal cells. In animal cells the plasma membrane of “the parent cell pinches inward along the cell’s equator until the two daughter cells form.” this creating a new cell. However in plant cells because it has a cell wall, the cell instead has to forms a cell plate along the equator of the parent cell. The cell plate forms between the cells and eventually a new cell wall and plasma membrane are created, making new cell when they split in half. |
2) What is the outcome of mitosis? The outcome of mitosis is that two genetically identical cells are made, this would be both the parent cell and daughter cell.
links used:
1)http://www.cellsalive.com/cell_cycle.htmhttp://www.biology4kids.com/files/cell_nucleus.html
2) http://www2.le.ac.uk/departments/genetics/vgec/highereducation/topics/cellcycle-mitosis-meiosis
3) http://www.ck12.org/user:d2Fsc3RvbkBuY21jcy5uZXQ./book/CK-12-Biology/r42/section/4.2/
4) http://www.answers.com/Q/What_are_the_final_outcomes_of_mitosis_and_meiosis
1)http://www.cellsalive.com/cell_cycle.htmhttp://www.biology4kids.com/files/cell_nucleus.html
2) http://www2.le.ac.uk/departments/genetics/vgec/highereducation/topics/cellcycle-mitosis-meiosis
3) http://www.ck12.org/user:d2Fsc3RvbkBuY21jcy5uZXQ./book/CK-12-Biology/r42/section/4.2/
4) http://www.answers.com/Q/What_are_the_final_outcomes_of_mitosis_and_meiosis