Chapter 10 Questions

Chapter 10 Questions

>>>p.243 1-5
1.) The larger a cell becomes, the more demands the cell places on it's DNA and the more trouble the cell has moving enough nutrients and wastes across the cell membrane.
2.) Suppose a small town that has a library with a few thousand books. If more people move into the town, the town will get larger. There will be more people borrowing books, and sometimes people may have to wait to borrow popular titles. Similarly, a larger cell would have to make greater demands on it's available genetic "library." In time, the cell's DNA would no longer be able to serve the increasing needs of the growing cell.
3.) Cell division
4.) Volume increases more rapidly than the surface area, causing the ratio of surface area to volume to decrease.
5.) Surface Area = 4 x 4 x 6 = 96 cm2

Volume = 4 x 4 x 4 = 64 cm3

Ratio of SA to V = 96/64 = 3:2

Surface Area (Length x Width x 6)

Volume (Length x Width x Height)

Ratio of Surface Area to Volume (SA/V = SA:V -simplified)

>>>p.249 1-6
1.) During the cell cycle, a cell grows, prepares for division, and divides to form two daughter cells, each of which then begins the cycle again.

2.) The four phases of Mitosis:

Prophase: The longest phase of mitosis, in which the chromatin condenses into chromosomes. The centrioles seperate, and a spindle begins to form. The nuclear membrane breaks down.

Metaphase: The chromosomes line up across the center of the cell. Each chromosome is connected to a spindle fiber at its centromere.

Anaphase: The sister chromatids seperate into individual chromosomes and are moved apart.

Telophase: The chromosomes gather at opposite ends of thecell and lose their distinct shapes. Two new nuclear membranes form.

3.) Interphase is the period of time between each cell division.

4.) Chromosomes are made up of DNA.

5.) Prokaryotic cells differ significantly from eukaryotic cells. They don't have a membrane-bound nucleus and instead of having chromosomal DNA, their genetic information is in a circular loop called a plasmid. Instead of going through elaborate replication processes like eukaryotes, bacterial cells divide by binary fission.

Binary Fission: A method of asexual reproduction that involves the splitting of a parent cell into two approximately equal parts.

http://library.thinkquest.org/C004535/prokaryotic_cells.html

>>>p.252 1-5
1.) Cyclins are proteins that trigger cell division. They regulate the timing of the cell cycle in eukaryotic cells.
2.) Cancer cells do not respond to the signals that regulate the growth of most cells. As a result, they form masses of cells called tumors that can damage the surrounding tissues.
3.) Cells will continue to grow until they come into contact with other cells.
4.) Cancer is a disorder in which some ofthe body's own cells lose the ability to control growth, is one such example. Cancer is a serious disease. Cancer is a disease of the cell cycle.
5.) When cytoplasm from a cell in mitosis is injected into another cell, the second cell enters mitosis. This is caused by cyclin, which triggers cell division. If cyclin were to be injected into a cell already in mitosis, I suggest that the cyclin would react as if it were "late for work" and spring to action, causing chaos throughout the cell. It could possibly deform the new cell as well as the old cell during mitosis.

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