Chapter 10 Questions

Pg. 243 #1-5


1. Give two reasons why cells divide

One of the reasons a cell divides is to prevent from a DNA 'overload'. Each time a cell grows larger in size, there is no replication of the DNA. If a cell were to grow without limit, an "information crisis" would occur.
The second reason a cell divides, is to keep the cell healthy in all senses. Food, oxygen and water, are

2. How is a cell's DNA like the books in a library?

The analogy used is referring to a small town being the cell. The books in a library are like DNA because, as the 'town' grows larger- there's more and more need for the books, and less will be available- until there will be a long waiting list and endless possibilities.

3. What is the solution to the problem caused by cell growth?

Cell growth is a problem that is more commonly fixed by cell division.

4. As a cell increases in size, which increase more rapidly, its surface or its volume?

When a cell increases in size, its volume increases more rapidly.

5. Calculate the surface area, volume, and ratio of surface area to volume of an imaginary cubic cell with a length of 4cm.

The surface area would be 4 x 4 x 6 = 96 cm2. Volume = 4 x 4 x 4 = 64 cm3. Ratio of SA to V = 96/64 = 3:2.


Pg. 249 #1-6


1. Name the main events of the cell cycle.

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. Describe what happens during each of the four phases of mitosis.

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

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.

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.

3. Describe what happens during 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.

4. What are chromosomes made of?

They are made up of coils of DNA.

5. How do prokaryotic cells divide?

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.

6.


Pg. 252 #1-5
(Randi helped me with these, that's why they're identical)

1. What chemicals regulate the cell cycle? How do they work?

Cyclins are proteins that trigger cell division. They regulate the timing of the cell cycle in eukaryotic cells.

2.What happens when cells do not respond to the signals that normally regulate their growth?

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. How do cells respond to contact with other cells?

Cells will continue to grow until they come into contact with other cells.

4. Why can cancer be considered a disease of the cell cycle?

Cancer is a disorder in which some of the 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. Write a hypothesis about what you think would happen if cyclin were injected into a cell that was in mitosis.

If cyclin was injected into a cell that was in mitosis then it would cause chaos in the cell.

p.257 1-10

1.The rate at which materials enter and leave through the cell membrane depends on the cell's....

a. volume

2. The process of cell division results in.....

c. two daughter cells

3. Pairs of identical chromatids are attached to each other at an area called the....

b. Centromere

4. If a cell has 12 chromosomes, how many chromosomes will each of its daughter cells have after mitosis?

c.12

5. At the beginning of cell division, a chromosome consists of two...

a. centromeres

6. The phase of mitosis during which chromosomes become visible and the centrioles separate from one another is....

a.Prophase

7. Metaphase is best illustrated in which figure?

b

8. The timing of the cell cycle in eukaryotic cells is controlled by a group of closely related proteins known as.....

b. cyclins

9. In the cell cycle, external regulators direct cells to....

a. speed up or slow down the cycle

10. Uncontrolled cell division occurs in....

a. Cancer