1. The rate at which materials enter and leave through the cell membrane depends on the cell's ......
volume
2. The process of cell division results in......
two daughter cells
3. Pairs of identical chromatids are attached to each other at an area called the..
centriole
4. If a cell has 12 chromosomes, how many chromosomes will each daughter cell have afrer mitosis?
12 chromosomes
5. At the beginning of cell division, a chromosome consists of two.....
centrioles
6.The phase of mitosis during which chromosomes become visible and the centrioles separate from one another is....
metaphase
7. Metaphase is best illustrated on which figure?
Figure B
8. The timing of the cell cycle in eukaryotic cell is controlled by a group of closely related proteins known as......
cyclins
9. In the cell cycle, external regulators direct cells to....
speed up or slow down the cell cycle
10. Uncontrolled cell division occure in......
cancer
Monday, January 7, 2008
10-3 Assessment (pg 252 1-5)
1. What chemicals regualate the cell cycle? How do they work?
Cyclins regulate the timing of the cell
2. What happens when cells do not respond to the signals that normally regulate their growth?
The form masses of cells called tumors that can damage the surrounding tissues.
3. How do cells respond to contact with other cells?
the form a mass. such as cancer
4. Why can cancer be considered a disease of the cell cycle?
It can be called a disease because it takes over the cell. It spreads throuhgout the cell and no scientist knows to stop it from spreading.
5. Write a hypothesis about what you think would happen if cyclin were injected into a cell that was in mitosis.
I think that the cell would stop the process it was in. It would come to a halt.
Cyclins regulate the timing of the cell
2. What happens when cells do not respond to the signals that normally regulate their growth?
The form masses of cells called tumors that can damage the surrounding tissues.
3. How do cells respond to contact with other cells?
the form a mass. such as cancer
4. Why can cancer be considered a disease of the cell cycle?
It can be called a disease because it takes over the cell. It spreads throuhgout the cell and no scientist knows to stop it from spreading.
5. Write a hypothesis about what you think would happen if cyclin were injected into a cell that was in mitosis.
I think that the cell would stop the process it was in. It would come to a halt.
10-2 Assessment (pg 249 1-6)
1. Name the main events if the cell cycle.
The main event is that a cell grows, prepares for division, and divides to form two new daughter cells.
2. Describe what happens during each of the four phases of mitosis.
Prophase: chromatin condence into chromosomes. The centrioles serperate, and a spindle begins to form. The nuclear membrane breaks down.
Metaphase: chromosomes line up across the center of the cell. Microtubules connect the centermere of each chromosome to poles of a spindle.
Anaphase: The sister chromatids serperate into individual chromosomes and are moved apart.
Telophase: The chromosomes gather at opposite ends of the cell and lose their distinct shapes. Two nuclear membranes form.
3. Describe what happens during interphase.
Interphase: The cell grows and replicates its DNA and centrioles.
4. What are chromosomes made of?
DNA
5. How do prokaryotic cells divide?
6. How is the cytokinesis in plant cells similiar to cytokinesis in animal cells? How is it different?
In animal cells the cell membraneos drawn inward until the cytoplasm is pinched into nearly two equal parts.
In a plant cell a structure known as the cell plate forms midway between the divided nuclei.
The main event is that a cell grows, prepares for division, and divides to form two new daughter cells.
2. Describe what happens during each of the four phases of mitosis.
Prophase: chromatin condence into chromosomes. The centrioles serperate, and a spindle begins to form. The nuclear membrane breaks down.
Metaphase: chromosomes line up across the center of the cell. Microtubules connect the centermere of each chromosome to poles of a spindle.
Anaphase: The sister chromatids serperate into individual chromosomes and are moved apart.
Telophase: The chromosomes gather at opposite ends of the cell and lose their distinct shapes. Two nuclear membranes form.
3. Describe what happens during interphase.
Interphase: The cell grows and replicates its DNA and centrioles.
4. What are chromosomes made of?
DNA
5. How do prokaryotic cells divide?
6. How is the cytokinesis in plant cells similiar to cytokinesis in animal cells? How is it different?
In animal cells the cell membraneos drawn inward until the cytoplasm is pinched into nearly two equal parts.
In a plant cell a structure known as the cell plate forms midway between the divided nuclei.
10-1 Section Assessment (pg 243 1-5)
1. Give two reasons why cells divide.
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. How is a cell's DNA like the books in a library?
A cell is like a library because if a town grows bigger the deman for books is higher, and so the library gets more books. It is the same with a cell because if you get bigger the demand for more "books" is greater so the cell makes more.
3.What is the solution to the problems caused by cell growth?
they must divide as they grow
4. As a cell increases in size, which increases more rapidly, it's surface area or it's volume?
the volume increase much more rapidly
5. Calculate the surface area, volume, and ratio of surface area to volume of an imaginary cubic cell with a length of 4 cm.
The area of the surface is 96 cm cubed.
The volume is 64cm cubed.
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. How is a cell's DNA like the books in a library?
A cell is like a library because if a town grows bigger the deman for books is higher, and so the library gets more books. It is the same with a cell because if you get bigger the demand for more "books" is greater so the cell makes more.
3.What is the solution to the problems caused by cell growth?
they must divide as they grow
4. As a cell increases in size, which increases more rapidly, it's surface area or it's volume?
the volume increase much more rapidly
5. Calculate the surface area, volume, and ratio of surface area to volume of an imaginary cubic cell with a length of 4 cm.
The area of the surface is 96 cm cubed.
The volume is 64cm cubed.
Saturday, January 5, 2008
Cancer
Cancer: a malignant and invasive growth or tumor, esp. one originating in epithelium, tending to recur after excision and to metastasize to other sites.
Cytokinesis and Cyclin
Cytokinesis: the division of the cell cytoplasm that usually follows mitotic or meiotic division of the nucleus.
http://img.sparknotes.com/figures/D/d756b5b73abe2974f3521a828791899f/cytokinesis.gif
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.
http://www.nature.com/nrm/journal/v8/n2/images/nrm2105-f1.jpg
Anaphase and Telophase
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.
botit.botany.wisc.edu/images/130/Mitosis
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