BSC 118: Chapter 12 My Labs Plus

In the figure above, mitosis is represented by which number?

IV

A cell containing 92 chromatids at metaphase of mitosis would, at its completion, produce two nuclei each containing how many chromosomes?

46

Which of the following are primarily responsible for cytokinesis in plant cells?

Golgi-derived vesicles

Where do the microtubules of the spindle originate during mitosis in animal cells?

centrosome

As in most areas of biology, the study of mitosis and the cell cycle involves a lot of new terminology. Knowing what the different terms mean is essential to understanding and describing the processes occurring in the cell.

1. DNA replication produces two identical DNA molecules, called SISTER CHROMATID(S), which separate during mitosis. 2. After chromosomes condense, the CENTROMERE(S) is the region where the identical DNA molecules are most tightly attached to each other. 3. During mitosis, microtubules attach to chromosomes at the KINETOCHORE(S) 4. In dividing cells, most of the cell's growth occurs during INTERPHASE 5. The MITOTIC SPINDLE(S) is a cell structure consisting of microtubules, which forms during early mitosis and plays a role in cell division. 6. During interphase, most of the nucleus is filled with a complex of DNA and protein in a dispersed form called CHROMATIN 7. In most eukaryotes, division of the nucleus is followed by CYTOKINESIS, when the rest of the cell divides. 8. The CENTROSOME(S) are the organizing centers for microtubules involved in separating chromosomes during mitosis.

As the chromosomes of a parent cell are duplicated and distributed to the two daughter cells during cell division, the structure of the chromosomes changes. Answer the three questions for each phase of the cell cycle by dragging the yes and no labels to the appropriate locations in the table. Note: Assume that by the end of the M phase, the parent cell has not yet divided to form two daughter cells.

Are sister chromatid present in all or part of this phase? G1-no S-yes G2-yes Beginning of M-yes End of M-no Is the DNA condensed in all or part of this phase? G1- no S-no G2-no Beginning of M-yes End of M-yes Does the cell contain twice as much DNA in this phase as it did in the G1 phase? G1- no S-yes G2-yes Beginning of M- yes End of M-yes

The cell cycle represents the coordinated sequence of events in the life of a cell from its formation to its division into two daughter cells. Most of the key events of the cell cycle are restricted to a specific time within the cycle. In this exercise, you will identify when various events occur during the cell cycle. Recall that interphase consists of the G1, S, and G2 subphases, and that the M phase consists of mitosis and cytokinesis.

a. non-dividing cells exit cell cycle b. at this point, cell commits to go through the cycle c. DNA replicate d. centrosome replicates e. mitotic spindle begins to form f. cell divides, forming two daughter cells