Genetics
The science of heredity, dealing with resemblances and differences of related organisms resulting from the interaction of their genes and the environment.
True-breeding
A true breeding organism, sometimes also called a pure-bred, is an organism having certain biological traits which are passed on to all subsequent generations when bred with another true breeding organism for the same traits. In other words, to "breed true" means that two organisms with a particular, heritable phenotype produce only offspring with that (same) phenotype.
Trait
A genetically determined characteristic or condition: a recessive trait.
Hybrid
The offspring of genetically dissimilar parents or stock, especially the offspring produced by breeding plants or animals of different varieties, species, or races.
Gene
The basic physical unit of heredity; a linear sequence of nucleotides along a segment of DNA that provides the coded instructions for synthesis of RNA, which, when translated into protein, leads to the expression of hereditary character.
Allele
Any of several forms of a gene, usually arising through mutation, that are responsible for hereditary variation.
Segregation
The separation of allelic genes into different gametes during meiosis.
Gamete
A mature sexual reproductive cell, as a sperm or egg, that unites with another cell to form a new organism.
Probability
The quality or fact of being probable.
Punnett Square
The Punnett square is a diagram designed by Reginald Punnett and used by biologists to determine the probability of an offspring having a particular genotype.
Homozygous
Having identical pairs of genes for any given pair of hereditary characteristics.
Heterozygous
Having dissimilar pairs of genes for any hereditary characteristic.
Phenotype
The appearance of an organism resulting from the interaction of the genotype and the environment.
Genotype
The genetic makeup of an organism or group of organisms with reference to a single trait, set of traits, or an entire complex of traits.
Homologous
Having the same alleles or genes in the same order of arrangement: homologous chromosomes.
Diploid
Having two similar complements of chromosomes.
Haploid
Pertaining to a single set of chromosomes.
Meiosis
Part of the process of gamete formation, consisting of chromosome conjugation and two cell divisions, in the course of which the diploid chromosome number becomes reduced to the haploid.
Tetrad
A group of four chromatids formed by synapsis at the beginning of meiosis.
Crossing Over
The exchange of genetic material between homologous chromosomes that occurs during meiosis and contributes to genetic variability.
Gene Map
A graphic representation of the arrangement of genes or DNA sequences on a chromosome.
Monday, February 11, 2008
Thursday, January 10, 2008
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
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
Friday, January 4, 2008
Cell Growth and Division
Vocabulary
Cell Division
The process by which a cell divides to form two daughter cells. Upon completion of the process, each daughter cell contains the same genetic material as the original cell and roughly half of its cytoplasm.
Chromatid
Either of the two daughter strands of a replicated chromosome that are joined by a single centromere and separate during cell division to become individual chromosomes.
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 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.
Cell Cycle
The cycle of growth and asexual reproduction of a cell, consisting of interphase followed in actively dividing cells by prophase, metaphase, anaphase, and telophase.
Mitosis
The usual method of cell division, characterized typically by the resolving of the chromatin of the nucleus into a threadlike form, which condenses into chromosomes, each of which separates longitudinally into two parts, one part of each chromosome being retained in each of two new cells resulting from the original cell.
Prophase
The first stage of mitosis, during which the chromosomes condense and become visible, the nuclear membrane breaks down, and the spindle apparatus forms at opposite poles of the cell.
Centriole
A small, cylindrical cell organelle, seen near the nucleus in the cytoplasm of most eukaryotic cells, that divides in perpendicular fashion during mitosis, the new pair of centrioles moving ahead of the spindle to opposite poles of the cell as the cell divides: identical in internal structure to a basal body.
Spindle
A 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 of mitosis and meiosis, following prophase and preceding anaphase, during which the chromosomes are aligned along the metaphase plate.
Anaphase
The stage of mitosis and meiosis in which the chromosomes move to opposite ends of the nuclear spindle.
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.
Cytokinesis
The division of the cell cytoplasm that usually follows mitotic or meiotic division of the nucleus.
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.
Cancer
A malignant and invasive growth or tumor, esp. one originating in epithelium, tending to recur after excision and to metastasize to other sites.
Cell Division
The process by which a cell divides to form two daughter cells. Upon completion of the process, each daughter cell contains the same genetic material as the original cell and roughly half of its cytoplasm.Chromatid
Either of the two daughter strands of a replicated chromosome that are joined by a single centromere and separate during cell division to become individual chromosomes.
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 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.Cell Cycle
The cycle of growth and asexual reproduction of a cell, consisting of interphase followed in actively dividing cells by prophase, metaphase, anaphase, and telophase.Mitosis
The usual method of cell division, characterized typically by the resolving of the chromatin of the nucleus into a threadlike form, which condenses into chromosomes, each of which separates longitudinally into two parts, one part of each chromosome being retained in each of two new cells resulting from the original cell.Prophase
The first stage of mitosis, during which the chromosomes condense and become visible, the nuclear membrane breaks down, and the spindle apparatus forms at opposite poles of the cell.Centriole
A small, cylindrical cell organelle, seen near the nucleus in the cytoplasm of most eukaryotic cells, that divides in perpendicular fashion during mitosis, the new pair of centrioles moving ahead of the spindle to opposite poles of the cell as the cell divides: identical in internal structure to a basal body.Spindle
A 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 of mitosis and meiosis, following prophase and preceding anaphase, during which the chromosomes are aligned along the metaphase plate.Anaphase
The stage of mitosis and meiosis in which the chromosomes move to opposite ends of the nuclear spindle.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.Cytokinesis
The division of the cell cytoplasm that usually follows mitotic or meiotic division of the nucleus.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.
Cancer
A malignant and invasive growth or tumor, esp. one originating in epithelium, tending to recur after excision and to metastasize to other sites.
Thursday, January 3, 2008
Aristotle
Aristotle
Under the alias of Aristotle, I am posting as a female.
I am fifteen years old, and very artistic. I love drawing, reading, writing, and surfing the internet. I am a fan of anime, which is a form of japanese artwork. I can speak Chinese, and a bit of Japanese, and plan on becoming a Graphic Designer upon growing older.
I was born in Colorado, and have never lived elsewhere, however I may be moving to Sioux Falls, South Dakota shortly. My mom's best friend Jori and her two children Saraya and Nydjah live there. I first lived in Denver, which is more of a large smelly city, then moved to Aurora, which is a bit of inbetween, then finally to Parker- which is mostly lots of land, from what I've seen. I don't own a job, but I do wish to work at Hot Topic when I turn sixteen in five months. My favorite subject is probably Drawing And Painting, Biology, or Honors English II.
I have four siblings. Two brothers, and two sisters. My oldest brother's name is Cole, and he is eight years old. My second brother's name is Austin, and he is also eight- but not a twin. My oldest sister's name is Chloe, and she is six. The youngest of my siblings is Chylie, and she turned two. My dad's in the military, and is currently in Iraq under mechanic work.
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