The division of nuclear material in which each new nucleus obtains the same number of chromosomes and the same nuclear code as the original nucleus is call mitosis. Mitosis occurs in four phases. Interphase occurs between mitosis.
Interphase: Cell contains easily seen nucleus and nucleolus- chromosomes appear as fine dots within nucleus Mitosis: 4 steps
Prophase – cell nucleus enlarged –nucleolus no longer visible- chromosomes appear as short strands within nucleus.
Metaphase – chromosomes long and thin strands – chromosomes lined up along cell center and look like “spider on a mirror”.
Anaphase – two sets of separate chromosomes can be seen – look as if they are being pulled apart from one another.
Telophase – chromosomes appear at opposite ends of cell – middle of cell has line across center that divides it almost into two new cells. Cytokinesis: appear as two daughter cells, small and side by side – then starts in interphase again.
Use notes from lecture, pictures on the board, and the description from above to answer the following questions for each phase:
1. Describe the contents of a nucleus during interphase._____________________________________________ 2. Are a nucleolus and nuclear membrane present in the cell? ________________________________________ 3. Are distinct rod-shaped structures called chromosomes easily observed in the nucleus at this time? ________ 4. Are chromosomes present in cells during interphase? _____________________________________________ 5. What term is used to describe nuclear contents during interphase? __________________________________ 6. What important event occurs to chromosomes during interphase? ___________________________________ 7. What other important events occur during interphase? ____________________________________________
8. Are chromosomes now visible during prophase? _______________________________________ 9. Describe the changes...