Thursday, January 10, 2008

End of Chapter Review 1-10

1-10 page 257
1. A
2. C
3. C
4. 6
5. C
6. D
7. B
8. B
9. D
10. D

Reviwe 10.3

Pg. 252 Questions 1-5
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 dont 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 all messed up.

Review 10.2

10.2 Review
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.

Review 10.1

10.1 Pg. 243
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.Caculate the surface area, volume, and ratio of surface area to volume of an imaginary cubic cell with a lengh of 4 cm.: surface area = 96:volume = 64 cm2:ratio of surface area to volume = 3/2

Sunday, January 6, 2008

cell division-the cycle of growth and asexual reproduction of a cell, consisting of interphase followed in actively dividing cells by prophase, metaphase, anaphase, and telophase.
















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


























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


























centromere-The most condensed and constricted region of a chromosome, to which the spindle fiber is attached during mitosis.


























cell cycle-the cycle of growth and asexual reproduction of a cell, consisting of interphase followed in actively dividing cells by prophase, metaphase, anaphase, and telophase.


























mitosis-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.


























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.


























prophase-Cell Biology. 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.


























spindle-Cell Biology. a 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-
1.
Pathology.
a.
a malignant and invasive growth or tumor, esp. one originating in epithelium, tending to recur after excision and to metastasize to other sites.
b.
any disease characterized by such growths.

Friday, January 4, 2008

Biography


Hi, my alias name is Charles Darwin. I am a 89 year old female. I am very old and wrinkley. I like to bite my toe nails and Ilike to make jam. I love to milk cows. My hobbies are skydriving, bungee jump and I like to swim with great white sharks without a cage. Basically I am just the Average Joe.