Monday, February 11, 2008

genetics-the science of heredity, dealing with resemblances and differences of related organisms resulting from the interaction of their genes and the environment.
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http://www.ornl.gov/sci/techresources/Human_Genome/genetics.shtml


True-breeding-term used to describe organisms that produce offspring identical to themselves if allowed to self polluniate
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http://biology.about.com/bldeftruebreed.htm

Trait- A genetically determined characteristic or condition: a recessive trait.
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http://webspace.ship.edu/cgboer/genpsytraits.html


Hybrid-bred from two distinct races, breeds, varieties, species, or genera
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http://www.biology-online.org/dictionary/Hybrid



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.
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http://www.genetics.gsk.com/kids/genes01.htm

Allele- any of several forms of a gene, usually arising through mutation, that are responsible for hereditary variation.
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http://biology.about.com/od/geneticsglossary/g/alleles.htm

Segregation- the separation of allelic genes into different gametes during meiosis
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http://biology.about.com/library/glossary/bldefmenlawseg.htm

Gamete-a mature sexual reproductive cell, as a sperm or egg, that unites with another cell to form a new organism.
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http://www.biology-online.org/dictionary/Gamete

Probability-the relative possibility that an event will occur, as expressed by the ratio of the number of actual occurrences to the total number of possible occurrences.
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http://www.mathgoodies.com/lessons/toc_vol6.html

Punnett Square- in genetics, a type of grid used to show the gametes of each parent and their possible offspring; a type of grid that can indicate all the possible outcomes of a genetic cross;
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http://www.athro.com/evo/gen/punexam.html

Homozygous-Relating to a cell that has two identical alleles for a particular trait at corresponding positions on homologous chromosomes.
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http://biology.about.com/bldefhomozyg.htm

Heterozygous-Relating to a cell that has two different alleles at corresponding positions on homologous chromosomes.
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http://biology.about.com/bldefhetzyg.htm


Phenotype- the appearance of an organism resulting from the interaction of the genotype and the environment.
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http://www.brooklyn.cuny.edu/bc/ahp/BioInfo/SD.Geno.HP.html

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.
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http://www.iscid.org/encyclopedia/Genotype


Homologous-Similar in structure and evolutionary origin, though not necessarily in function, as the flippers of a seal and the hands of a human.
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http://www.merriam-webster.com/dictionary/homologous

Diploid-having two similar complements of chromosomes
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http://www.biology-online.org/dictionary/Diploid

Haploid-an organism or cell having only one complete set of chromosomes, ordinarily half the normal diploid number.
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http://www.biology-online.org/dictionary/Haploid

Tetrad-a group of four chromatids formed by synapsis at the beginning of meiosis.
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http://answers.yahoo.com/question/index?qid=20061030200732AAJD3T4



Crossing-Over-The exchange of genetic material between homologous chromosomes that occurs during meiosis and contributes to genetic variability.
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http://www.accessexcellence.org/RC/VL/GG/comeiosis.html


Gene Map-A graphic representation of the arrangement of genes or DNA sequences on a chromosome
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http://www.msnbc.msn.com/id/22827585/

Thursday, January 10, 2008

Review pg 157 1-10

1-10 page 257
1. A
2. C
3. C
4. 6
5. C
6. D
7. B
8. B
9. D
10. D

10.3 pg 252 Review

Pg. 252 Questions 1-5
1. Cyclins regulate the timing of the cell cycle in eukarotic cells.
2. Cancer cells do not resond to the growth of most cells. As a result, they form masses of cells called tumors that can damage the surrounding tissue.
3.chromosome damage builds up when cells respond to contact with other cells.
4. Cancer cells dont respond to the signals that would normally stop them dividing. Masses of cancer cells form tumors that can damage normal tissue. These cancer cells are from a cancer tumor in the large intestine.
5. If cyclin were incerted into a cell that was in mitosis, the timing would be all jacked up.

10.2 pg 249 1-6

10.2 Review
1. During the cell cycle, a cell grows, prpares for cell division and divide to form 2 daughter cells. each of which then begins the cell cyle again.
2. Biologists divide the events of mitosis into 4 phases: prophase, metaphase, anaphase and telophase.
3. The cell grows and replicates its DNA and centrioles.
4. Chromosomes are made up of DNA.
5.Prokayrote cells divide during anaphase.
6.Cytokinesis takes place in an animal cell, the cell membrane is drawn inward until the cytoplasm is pinched into two nearly equal parts.

Review 10.1 1-5

10.1 Pg. 243
1.Two reasons cells divide are (1) the larger the cell becomes, the more demands the cell places on its DNA and (2) the more trouble the cell has moving enough nutrients and wastes across the cell membrane.
2. A cells DNA is like the books in a library because it stays the same. In a a growing town, the library doesn't grow with it, it stays the same just like DNA in a cell--the DNA doesn't grow with the cell.
3. Cell division is the solution to the problems caused by cell growth.
4. As a cell increased in size, the cell's volume increases more rapidly than its surface area.
5. Caculate the surface area, volume, and ratio of surface area to volume of an imaginary cubic cell with a lengh of 4 cm.: surface area = 96:volume = 64 cm2:ratio of surface area to volume = 3/2

Friday, January 4, 2008

Vocab

cell division-
The process by which a cell divides into two or more cells. Among prokaryotes, cell division occurs by simple fission. Among eukaryotes, the cell nucleus divides first, and then a new cell membrane is formed between the nuclei to form the new cell. Cell division is used as a means of reproduction in organisms that reproduce asexually, as by fission or spore formation, and sexually reproducing organisms form gametes through cell division. Cell division is also the source of tissue growth and repair in multicellular organisms. The two types of cell division in eukaryotic organisms are mitosis and meiosis.
3 types:
Binary Fission
Mitosis
Meiosis

chromatid-


Either of the two daughter strands of a duplicated 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- he 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 process in cell division in eukaryotes in which the nucleus divides to produce two ne
w nuclei, each having the same number and type of chromosomes as the original. Prior to mitosis, each chromosome is replicated to form two identical strands (called chromatids). As mitosis begins, the chromosomes line up along the center of the cell by attaching to the fibers of the cell spindle The pairs of chromatids then separate, each strand of a pair moving to an o pposite end of the cell. When a new membrane forms around each of the two groups of chromosomes, division of the nucleus is complete. The four main phases of mitosis are prophase, metaphase, anaphase, and telophase. Compare meiosis.



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.


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 network of protein fibers that forms in the cytoplasm of a cell during cell division. The spindle grows forth from the centrosomes and attaches to the chromosomes after the latter have been duplicated, and the nuclear mem brane dissolves. Once attached, the spindle fibers contract, pulling the duplicate chromosomes apart to opposite poles of the dividing cell. See more at meiosis, mitosis.
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 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.

cytokinesis-the division of the cell cytoplasm that usually follows mitotic or meiotic division of the nucleus.





Cancer-
A disease characterized by any of various malignant neoplasms composed of abnormal cells that tend to proliferate rapidly and invade surrounding tissue. Without treatment such as chemotherapy or radiation, cancer cells can metastasize to other body sites and cause organ failure and death.


http://www.youtube.com/watch?v=VhkQP5g4EHo




Thursday, January 3, 2008

Biography

hello there!

I am The GREAT gargi5

in my free time i enjoy many activities such as... soccer..(love it).. basketball..(its pretty fun) and every other sport..ha I love the outdoors and i would rather be outdoors then indoors. I have 3 brohas. I have the coolest best friends ever... they are my homeskillets and slices! well you could call me a goof ball!

good bye for now my fellow friends.