Genetics-the branch of biology that studies heredity and variation in organisms
Friday, February 8, 2008
Chapter 11 Vocab
Genetics-the branch of biology that studies heredity and variation in organisms
Tuesday, January 8, 2008
Chapter 10 Questions
1. Give two reasons why cells divide.
-the larger a cell becomes, the more demands the cell places on its 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 the library?
Books are where all of the information is stored
3. What is the solution to the problems caused by cell growth?
the cell grows and replicates its DNA and centrioles
4. As a cell increases in size, which increases more rapidly, its surface area or its volume?
volume
5.Calculate the surface area, volume, and the ratio of surface area to volume of an imaginary cubic cell with a length of 4cm.
Surface Area: 96cm2 Volume: 64cm3 96/64= 3:2
p.249 #1-6:
1.Name the main events of the cell cycle.
- M phase -G1 phase -S phase -G2 phase
2. Describe what happens during each of the four phases of mitosis.
Prophase-nuclear envelope breaks down and strands of chromatin form into chromosomes. Metaphase-the duplicated chromosomes line up along the equatorial plate of the spindle. Anaphase-the daughter chromosomes move away from each other to opposite ends of the cell. Telophase-the chromosomes of daughter cells are grouped in new nuclei.
3.Describe what happens during interphase.
During the interphase, the nucleus is not undergoing any division of growth.
4. What are chromosomes made of?
each chromosome consists of two identical "sister" chromatids attached by a centromere.
5. How do prokaryotic cells divide?
Most Prokaryotic cells divide by a process called binary fission where a cell divides in half - forming two daughter cells which are genetically identical.
6. How is cytokinesis in plant cells similar to cytokinesis in plant cells? How is it different?Cytoplasm is divided in both cells but a plant cell forms a plate midway between divided nuclei while the animal cell's cytoplasm is pinched into two nearly equal parts.
p.252 #1-5:
1. What chemicals regulate the cell cycle? How do they work?
-Cyclins: regulate the timing of the cell cycle in eukaryotic cells
-Internal Regulators: proteins that respond to events inside the cell
-External Regulators: proteins that respond to events outside the cell
2.What happens when cells do not respond to the signals that normally regulate their growth?
They form masses of cells called tumors that can damage the surrounding tissues.
3. How do cells respond to contact with other cells? chromosome damage builds up when cells respond to contact with other cells.
4.Why can cancer be considered a disease of the cell cycle?
It does not respond to the signals the regulate its growth so its size keeps increasing and it spreads, and there is no control over 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 undergoing mitosis, then the cell would not be affected by it because cyclin regulates the timing of the cell cycle so everyhting will remain under control.
p.257 #1-10
1. The rate at which materials enter and leave through the cell membrane depends on the cell's:
Friday, January 4, 2008
Cell Growth and Division Vocabulary
cell division-The process by which a cell divides to form two daughter cells.
centromere-a specialized structure on the chromosome, appearing during cell division as the constricted central region where the two chromatids are held together and form an X shape.
interphase-the period of the cell cycle during which the nucleus is not undergoing division.Also called interkinesis.
mitosis-Celldivision in which the nucleus divides into nuclei containing the same number of chromosomes.
centriole-One of two cylindrical cellular structures that are composed of nine triplet microtubules and form the asters during mitosis.
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 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 mitosis or meiosis during which the chromosomes of daughter cells are grouped in new nuclei.
Thursday, January 3, 2008
Deborah Crocker
A little about me...
I have a brother who is a pain in the butt but very cute, and a sister that just turned 13 (DRAMA!). Also I play soccer and i love fashion! I guess you could say thats my thang! Haha but i love to hang out with all of my amazing friends and every once and awhile you can throw the fam in there too.