Thursday, January 10, 2008

Chapter 10 Questions

Page 243:

1. DNA "overlaod" and the ratio of surface area to volume are two reasons why cells divide.

2.The cells DNA is like the books in a library because the replication of DNA copies the genetic information and tranfers it to the two daughter cells that resemble books; the two daughter cells then have their very own information just like books. Therefore the daughter cells have information similiar to a book in a library.

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

4. As a cell increases in size its volume increases more rapidly than its surface area.

5. A cubic cell with a length of 4 cm, would have a surface area of 96cm squared, a volume of 64cm squared, and a ratio of 2:3.

Page 249:

1. The main events of the cell cycle is prophase, metaphase, anaphase, and telophase.

2. During prophase the nuclear membrane breaks down, the centrioles separates to opposite sides of the cell, a spindle starts to form, and chromatin condenses into chromosomes. During metaphase the chromosomes line up in the center of the cell and the spindle fibers connect to them from the centromere. The sister chromatids separate into individual chromosomes and move apart during anaphase. During the final stage, telophase, the chromosomes at opposite ends of the cell form two new nuclear membranes.

3. During interphase the cell grows and replicates its DNA and centrioles.

4. Chromosomes are made up of DNA and protien.

5. Cell division of eukaryotic and prokaryotic cells are for the most part very alike, expect in prokaryotes, after each daughter cell gets a comlete copy of their own genetic information, the rest of the procces is separating the contents of the cell into two parts.

6. Ckytokinesis in plant and animal cells are similar becuase a cell membrane is used to separate the cytoplasm. They are different because animal cells are pinched into two parts where as plant cells gradually develops into separating parts.

Page 252:

1. Chemicals that regulate the cell cylce are cyclins as well as internal and external regulators. They regulate the cell cycle by triggering cell division and controlling the timing of the process.

2. When cells do not respond to the signals that normally regulate cancer developes and creates tumors that can damage the surrounding tissues.

3. Cells respond to contact with other cells by not increasing in size.

4. Cancer can be considered a disease of the cell cycle because it causes a loss of control over the cell cylce.

5. If cyclin were injected into a cell that was in mitosis, then there would be less of a chance for something to go wrong and cell division would happen faster because cyclins controll the timing of cell division.

Page 257:

1. A: volume

2. C:two daughter cells

3. B:centromere

4. B: six

5. C: chromatids

6: A: Prophase

7: B

8: B:cyclins

9. A: speed up or slow down cell cycle

10. A: cancer

Monday, January 7, 2008

Cell Growth and Division vocabulary

Cell Division: the process by which a cell divides to form two daughter cells. Upon completion of the process, each daughter cell contains the same genetic material as the original cell and roughly half of its cytoplasm.

Chromatid: one of the two identical "sister" parts of a duplicated chromosome.

Centromere: the most condensed and constricted region of a chromosome, to which the spindle fiber is attached during mitosis.


Interphase: the stage in the development of a cell following mitosis or meiosis, during which the nucleus is not dividing. In cells that will undergo further division, the DNA in the nucleus is duplicated in preparation for the next division.



Cell cycle: the series of events involving the growth, replication, and division of a eukaryotic cell.



Mitosis: the process in cell division by which the nucleus divides, typically consisting of four stages, prophase, metaphase, anaphase, and telophase, and normally resulting in two new cells fromed by the original cell.





Prophase: the first stage of mitosis, during which the chromosomes condense and become visible, the nuclear membrane breaks down, and the spindle apparatus forms at opposite poles of the 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.


Spindle: 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 of mitosis and meiosis in which the chromosomes move to opposite ends of the nuclear spindle.



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 cytoplasm of a cell following the division of the nucleus during cell division.




Cyclin: any of a group of proteins active in controlling the cell cycle and in initiating DNA synthesis.



Cancer: disorder in wich some of the body's own cells lose the ability to control growth.






Sunday, January 6, 2008

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