Pg. 157

1. A
2. C
3. 6
4. C
5. D
6. B
7. B
8. D
9. D

10-2

1. During the cell cycle, a cell grows, prpares for cell division and divide to form 2 daughter cells. each of which then begins the cell cyle again.
2. Biologists divide the events of mitosis into 4 phases: prophase, metaphase, anaphase and telophase.
3. The cell grows and replicates its DNA and centrioles.
4. Chromosomes are made up of DNA.
5.Prokayrote cells divide during anaphase.
6.Cytokinesis takes place in an animal cell, the cell membrane is drawn inward until the cytoplasm is pinched into two nearly equal parts.

10-3

1. Cyclins regulate the timing of the cell cycle in eukarotic cells.
2. Cancer cells do not resond to the growth of most cells. As a result, they form masses of cells called tumors that can damage the surrounding tissue.
3.chromosome damage builds up when cells respond to contact with other cells.
4. Cancer cells don't respond to the signals that would normally stop them dividing. Masses of cancer cells form tumors that can damage normal tissue. These cancer cells are from a cancer tumor in the large intestine.
5. If cyclin were incerted into a cell that was in mitosis, the timing would be wrong.

10-1

1. Two reasons cells divide are (1) the larger the cell becomes, the more demands the cell places on its DNA and (2) the more trouble the cell has moving enough nutrients and wastes across the cell membrane.

2. A cells DNA is like the books in a library because it stays the same. In a a growing town, the library doesn't grow with it, it stays the same just like DNA in a cell--the DNA doesn't grow with the cell.

3. Cell division is the solution to the problems caused by cell growth.

4. As a cell increased in size, the cell's volume increases more rapidly than its surface area.

5. Surface Area: 96cm2 Volume: 64cm3; 96:64= 3:2

cell division--the division of a cell in reproduction or growth. http://www.youtube.com/watch?v=VhkQP5g4EHo&NR=1

chromatid--one of two identical chromosomal strands into which a chromosome splits longitudinally preparatory to cell division.

centromere--a specialized structure on the chromosome, appearing during cell division as the constricted central region where the two chromatids are held together and form an X shape.

interphase--the period of the cell cycle during which the nucleus is not undergoing division, typically occurring between mitotic or meiotic divisions.

cell cycle--the usual method of cell division, characterized typically by the resolving of the chromatin of the nucleus into a threadlike form, which condenses into chromosomes, each of which separates longitudinally into two parts, one part of each chromosome being retained in each of two new cells resulting from the original cell. http://www.youtube.com/watch?v=JmiSg_bEv6I&feature=related

prophase--the first stage of mitosis or meiosis in eukaryotic cell division, during which the nuclear envelope breaks down and strands of chromatin form into chromosomes.

centriole--a small, cylindrical cell organelle, seen near the nucleus in the cytoplasm of most eukaryotic cells, that divides in perpendicular fashion during mitosis, the new pair of centrioles moving ahead of the spindle to opposite poles of the cell as the cell divides: identical in internal structure to a basal body.

spindle--shaped structure, composed of microtubules, that forms near the cell nucleus during mitosis or meiosis and, as it divides, draws the chromosomes to opposite poles of the cell.

metaphase--the stage in mitosis or meiosis in which the duplicated chromosomes line up along the equatorial plate of the spindle.

anaphase--the stage in mitosis or meiosis following metaphase in which the daughter chromosomes move away from each other to opposite ends of the cell.

telophase--the final stage of meiosis or mitosis, in which the separated chromosomes reach the opposite poles of the dividing cell and the nuclei of the daughter cells form around the two sets of chromosomes.

cytokinesis--the division of the cell cytoplasm that usually follows mitotic or meiotic division of the nucleus.

cyclin--A class of proteins that fluctuate in concentration at specific points during the cell cycle and that regulate the cycle by binding to a kinase.

cancer--any malignant growth or tumor caused by abnormal and uncontrolled cell division; it may spread to other parts of the body through the lymphatic system or the blood stream. http://www.youtube.com/watch?v=bDjDw18HJto&feature=related

Biography

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I am extremely excited to be blogging today.

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