Question

Please help me with this. I'm so lost. If you could be detailed/help explain, I would appreciate it a lot. Thank you.

Topic: Onions, Lily Anther, Mitosis and Meiosis!: Prophase I, Prometaphase I, Metaphase I, Anaphase I, Telophase I, Cytokinesis Prophase II, Metaphase II, Anaphase II, Telophase II, Cytokinesis II Tetrads Intro Pretend you were in the lab and you took some onion root tips and some lily and viewed them under the lab in a microscope. We are Concerned with Mitosis 1A. When you looked at onion cells, we had you look at a specific region of the root tip to find cells undergoing mitosis. Why would we have you look at the root tip for those cells, and not other cells within the onion? (3 pts) 1B. In which stage of mitosis do we analyze a cell's karyotype and why? (2 pts) 1C. For this stage, draw what the chromosomes look like for a diploid cell that normally has 2 sets of 3 chromosomes (2n- 6) (4 pts)

Answer 1

1A. Cells in the onion root-tip are actively dividing cells.

Many cells in the onion root-tip would be undergoing different stages of the mitotic cycle.

These cells can be tapped on a slide which will flatten the chromosomes and prepared to study mitosis under a compound microscope.

1B. Karyotype is the pictorial representation of the total number of chromosomes in a cell. It is best studies during mitotic metaphase as chromosomes at this stage have condensed and are more visible align themselves at the equatorial plane. Kinetochore microtubules align the chromosomes at the equatorial plate of the cell.

1C

1D need more information. Have to see the specific slides first

1E. Unless the cells are not properly aligned at the metaphase plate, cells won't proceed to anaphase stage, this is because of the positive control of cell cycle regulated by checkpoints (spindle checkpoint). Kinetochores of the sister chromatids should be attached to opposite poles at metaphase, only then can cell allow the transition to anaphase.