The questions are 2 Which cell cycle phase requires the long

The questions are..

2. Which cell cycle phase requires the longest time for completion?

3. Which mitotic phase requires the longest time for completion?

4. What important changes are occurring in the nucleus during the longest phase of mitosis? Does this justify the amount of time spent in the phase?

5. Which mitotic phase requires the next longest time for completion?  

6. Which mitotic phase requires the shortest time for completion?    7. Are there any assumptions made in using this method to estimate the timing of phases within the cell cycle? What are the most important assumptions?


In the scientific method (hypothetico-deductive method), complementary hypotheses are evaluated to determine the best explanation for a natural phenomenon. The scientific researcher develops both a testable hypothesis (sometimes called an alternative hypothesis) and a complementary null hypothesis. Then the researcher collects data to evaluate both hypotheses, and if the data is sufficient, determines that one of the hypotheses is the better explanation.


8. Cancer is a disease that involves irregular accumulation of cells within the body tissues.   Develop a pair of hypotheses about cancer that address the length of the phases within the cell cycle and the length of the cell cycle itself. Please list your hypotheses along with a brief (only one or two sentences) explanation explaining why you have chosen those hypotheses.  2.

Solution

ans 2: Interphase requires the longest time for completion,about 78 % of the time of Cell cycle the cell remain in this non dividing stage.IN this phase DNA replicates cells, become larger accumulate substances that are essential for cell division, growth and development.

ans 3: Prophase is the longest mitotic phase, which requires about 14 % of the time of cell cycle.  

ans 4: Imortant changes occuring during prophase are:

During early prophase:
The chromosome begins to condense.
The mitotic spindle begins to form. As we know spindle fibers plays an imortant role of organizing the chromosomes and move around during the mitotic phase.
The nucleolus disappears,this shows that the protein synthesis stops and the nucleus is ready to break down.
During late prophase:
Chromosomes become compact
Nuclear envelop breakes down releasing the chromosomes.
Mitotic spindleelongates and gets attached to chromosome.
  
This phase takes longer than the others because the nuclear envelope fragments and the microtubules have to attach to the chromosomes.
Yes, time spend in this phase is justified as without spindle fibers attachment to the chromosomes and nuclear envelope breakdown the cell division is not possible.

Ans 5: The Metaphase of the mitotic phase requires the next longest time for completion about 4% of the cellcycle time is consumed during this phase. In this phase lining up of chromosome at metaplate occurs, and the check point for two kinetochores of each chromosome are correctly attached to microtubules from opposite spindle poles or not.

Ans 6: Anaphase of the mitotic phase requires the shortest time for completion it only takes about 0.8 percent of the cell cycle to complete. Dring this phase the sister chromatids are pulled apart to opposite poles.Due to which each daughter cell to have an identical copy of each of the original cell’s chromosomes.