The Godfather of the Biomafia

Chapter 11 Vocab. Genetics

2008-02-08T07:55:00.000-07:00

G E N E T I C S
Chapter 11

More info. on Genetics go to: http://www.dnaftb.org/dnaftb/

Genetics - The branch of biology that deals with heredity, especially the mechanisms of hereditary transmission and the variation of inherited characteristics among similar or related organisms.

True-breeding - Term used to describe organisms that produce offspring identical to themselves if allowed to self-polinate.

Trait - Specific characteristic that varies from one individual to another.

Hybrid - The offspring of two animals or plants of different breeds, varieties, species, or genera, esp. as produced through human manipulation for specific genetic characteristics.

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 - One of a number of different forms of a gene.

Segregation - Seperation of allele during gamete formation.

Gamete - Specialized cell involved in sexual reproduction.

Probability - likelihood that a particular event will occur.

Punnett Square - Diagram showing the gene combinations that might result from a genetic cross.

Homozygous - (Same) - Term used to refer to an organism that has to identical alleles for a particular trait (AA, ss, pp, RR, etc.)

Heterozygous - (Different) - Term used to refer to an organism that has two different alleles for the same trait (Aa, Ss, Pp, Rr, etc.)

Phenotype - (See) - Physical characteristics of an organism (Brown hair, Blue eyes, etc.)

Genotype - (Letter) - Genetic make up of an organism (Aa, AA, aa, SS, Ss, ss, PP, Pp, pp, etc.)

Homologous - Term used to refer to chromosomes that each have a corresponding chromosome from the opposite-sex parent.

Diploid - Term used to refer to a cell that contains both sets of homologous chromosomes.

Haploid - Term used to refer to a cell that contains only a single set of chromosomes and therefore only a single set of genes.

Meiosis - Process by which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell.

Tetrad - Structure containing 4 chromatids that form during meiosis.

Crossing-Over - Process in which homologous chromosomes exchange portions of their chromatids during meiosis.

Gene Map - Diagram showing the relative locations of each known gene on a particular chromosome.

ENLARGE PICTURE ABOVE

Chapter 10 Questions

2008-01-09T22:06:00.000-07:00

Chapter 10 Questions

>>>p.243 1-5
1.) 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.) Suppose a small town that has a library with a few thousand books. If more people move into the town, the town will get larger. There will be more people borrowing books, and sometimes people may have to wait to borrow popular titles. Similarly, a larger cell would have to make greater demands on it's available genetic "library." In time, the cell's DNA would no longer be able to serve the increasing needs of the growing cell.
3.) Cell division
4.) Volume increases more rapidly than the surface area, causing the ratio of surface area to volume to decrease.
5.) Surface Area = 4 x 4 x 6 = 96 cm2

Volume = 4 x 4 x 4 = 64 cm3

Ratio of SA to V = 96/64 = 3:2

Surface Area (Length x Width x 6)

Volume (Length x Width x Height)

Ratio of Surface Area to Volume (SA/V = SA:V -simplified)

>>>p.249 1-6
1.) 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.) The four phases of Mitosis:

Prophase: The longest phase of mitosis, in which the chromatin condenses into chromosomes. The centrioles seperate, and a spindle begins to form. The nuclear membrane breaks down.

Metaphase: The chromosomes line up across the center of the cell. Each chromosome is connected to a spindle fiber at its centromere.

Anaphase: The sister chromatids seperate into individual chromosomes and are moved apart.

Telophase: The chromosomes gather at opposite ends of thecell and lose their distinct shapes. Two new nuclear membranes form.

3.) Interphase is the period of time between each cell division.

4.) Chromosomes are made up of DNA.

5.) 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.

Binary Fission: A method of asexual reproduction that involves the splitting of a parent cell into two approximately equal parts.

http://library.thinkquest.org/C004535/prokaryotic_cells.html

>>>p.252 1-5
1.) Cyclins are proteins that trigger cell division. They regulate the timing of the cell cycle in eukaryotic cells.
2.) 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.) Cells will continue to grow until they come into contact with other cells.
4.) Cancer is a disorder in which some ofthe 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.) When cytoplasm from a cell in mitosis is injected into another cell, the second cell enters mitosis. This is caused by cyclin, which triggers cell division. If cyclin were to be injected into a cell already in mitosis, I suggest that the cyclin would react as if it were "late for work" and spring to action, causing chaos throughout the cell. It could possibly deform the new cell as well as the old cell during mitosis.

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

Cell Growth and Division

2008-01-06T00:50:00.000-07:00

Cell Growth and Division

Definitions and info.

http://dictionary.reference.com/

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. Also called interkinesis.

Cell Cycle: The series of events involving the growth, replication, and division of a eukaryotic cell.

Mitosis: 1.) The process in cell division by which the nucleus divides, typically consisting of four stages, prophase, metaphase, anaphase, and telophase, and normally resulting in two new nuclei, each of which contains a complete copy of the parental chromosomes. Also called karyokinesis.

2.) The entire process of cell division including division of the nucleus and the cytoplasm.

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: Either of a pair of cylinder-shaped bodies found in the centrosome of most eukaryotic organisms other than plants. During cell division (both mitosis and meiosis), the centrioles move apart to help form the spindle, which then distributes the chromosomes in the dividing cell.

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 cell division in mitosis or meiosis in which the doubled set of chromosomes separates into two identical groups that move to opposite ends of the cell. Anaphase is preceded by metaphase and followed by telophase.

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 cytoplasm of a cell following the 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: Any of various malignant neoplasms characterized by the proliferation of anaplastic cells that tend to invade surrounding tissue and metastasize to new body sites.

Link

2008-01-03T07:56:00.000-07:00

Link to biology blog.