Page 234
Q: Give two reasons why cells divide.
A: Cells divide because as the cell grows it demands more places on DNA and the more trouble the cell has moving enough nutrients and wastes across the cell membrane.
Q: How is a cell's DNA like the books in the library?
A: The cell's DNA is like books in a library because like a book the cell contains material that will help make even more DNA or books.
Q: What is the solution to the problems caused by cell growth?
A: The solution to problem caused by the cell growth are the daughter cells that help contain more genetic material.
Q:As a cell increases in size, which increases more rapidly, its surface area or its volume?
A: When the cell increases in size the volume increases more rapidly that surface area.
Q: Calculate the surface area, volume, and ratio of the surface area of an imaginary cubic cell with a lenghe of 4 cm.
A: Surface Area- (4)(4)(6) = 96 cm squared
Volume-(4)(4)(4)= 64 cm cubed
Ratio-3:2
Page 249
Q:Name the main events of the cell cyle.
A: The main events of the cell cycle are G1 Phase, S Phase, and G2 Phase.
Q:Describe what happens during each of the four phases of mitosis.
A: Prophase - Longest phase of mitosis, the chromosomes become visible, and the two tiny structures in the cytoplasm near the nuclear envelope go to opposite poles of the nucleus
Metaphase- The chromosomes line up across the center of the cell. Microtubles then connenct the centromere to the spindles.
Anaphase- The centromeres join the sister chromatid that are seperate and then become individual chromosomes. The chromosomes continue moving until they are near the poles.
Telophase- The chromosomes disperse into a tangle of dense material and the nuclear envelope re-forms around each cluster of chromosomes. Then the spindles begin to break apart and the nucleolus becomes visible.
Q: Describe what happens during interphase.
A: During interphase the cell grows and replicate DNA.
Q: What are chromosomes made of?
A: Chromosomes are made up of DNA and proteins.
Q: How do prokaryotic cells divide?
A: Prokaryotic cells divide like eukaryotic cells/
Q: How is cytokinesis in plant cells similar to cytokinesis in animal cells?
A: The are both similar because they both use a membrane to help seperate the cytoplasm.
Page 252
Q: What chemicals regulate the cell cycle? How do they work?
A: Cyclins regulate the timing of the cell cycle. The cyclins regulate the timing of the cell cycle by being injected into a nondividing cell and that would cause a mitotic spindle.
Q:What happens when cells do not respond to the signals that respond that normally regulate growth?
A: When the cells can not respond to the signals that normally regulate growth this can cause cancer.
Q: How do cells respond to contact with other cells?
A: Cells respond to eachother by not growing.
Q: Why can cancer be considered a disease of the cell cycle?
A: Cancer can be considered a disease to the cell cycle because the cancer cells have a defect in a gene call p53 which stops the cells growth so it doesn't grow too big. As this problem starts to increase the cells lose the information needed to respond to the cell signals and to control growth.
Q: Write a hypothesis about what you think would happen if cylcin were injected into a cell that was in mitosis.
A: I think that if cylcin were injected into a cell during mitosis it would not regulate the timing of the cell cycle because it would be so busy trying to regulate the process of mitosis.
Page 257
Q: The rate at which materials enter and leave through the cell membrane depends on the cell's...
A: Volume
Q: The process of cell division results in...
A: Two daughter cells
Q: Pairs of identical chromatids are attached to eachother at an area called the ...
A: centromere
Q: If a cell has 12 chromosomes, how many chromosomes will each of its daughter cells have after mitosis?
A: Six
Q: At the beginning of cell division, a chromosome consists of two...
A: chromatids
Q: The phase of mitosis during which chromosomes become visible and the centrioles seperate from one antother is...
A: Prophase
Q: Metaphase is best illustrated in which figure?
A: C
Q: The timing fo the cell cycle in eukaryotic cells is controlled by a group of clsely related proteins known as...
A: Cyclins
Q: In the cell cycle, external regulators direct cells to...
A: speed up or slow down cell cycle
Q: Uncontrolled cell division occurs in...
A: Cancer
Wednesday, January 9, 2008
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