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

True-breeding-term used to describe organisms that produce offspring identicle to themselves if allowed to self pollinate.

http://www.sparknotes.com/testprep/books/sat2/biology/chapter7section3.rhtml

Trait- a distinguishing characteristic or quality

Hybrid- the offspring of two humans or animals or plants of different breeds
Gene- A hereditary unit that occupies a specific location on a chromosome, determines a particular characteristic in an organism by directing the formation of a specific protein, and is capable of replicating itself at each cell division.
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 likelihood of getting certain genes
Punnett Square- type of grid used to show the gametes of each parent and their possible offspring
Homozygous-Having the same alleles at a one or more gene loci on homologous chromosome segments.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- genetic makeup of an organism
Homologous- term used to refer to an organism that each have a corresponding chromosome from the opposite-sex partnerDiploid- term used to refer to a cell that contains both sets of homologous chromosomesHaploid- pertaining to a single set of chromosomesMeiosis- 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

http://youtube.com/watch?v=D1_-mQS_FZ0

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 variabilityGene Map- an arrangement of genes on a chromosome

Book questions

Page 243
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?
~The volume incresses more rapidly
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
Page 249
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 that are 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.
Page 252
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?
~ Damage to chromosome 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 the cyclin regulates the timing of the cell cycle.
Page 257
1. The rate at which materials enter and leave through the cell membrane depends on the cell's:
~Volume.
2. The process of cell division results in:
~Two daughter cells.
3.Pairs of identical chromatids are attached to each other at an area called the:
~Centromere.
4. If a cell has 12 chromosomes, how many chromosomes will each of its daughter cells have after mitosis?
~12
5.At the beginning of cell division, a chromosome consists of two:
~Chromatids.
6. The phase of mitosis during which chromosomes become visible and the centrioles separate from one another is:
~Prophase.
7. Metaphase is best illustrated in which figure?
~Metaphase was illustrated in figure B.
8. The timing of the cell cycle in eukaryotic cells is controlled by a group of closely related proteins known as:
~Cyclins.
9.In the cell cycle, external regulators direct cells to:
~Speed up or slow down the cycle.
10. Uncontrolled cell division occurs in:
~Cancer.

Vocab

Cell Division- the division of a cell in reproduction or growth Chromatid- one of two identical strands into which a chromosome splits during mitosis
Centromere- The most condensed and constricted region of a chromosome, to which the spindle fiber is attached during mitosis Interphase- The stage of a cell between two successive mitotic or meiotic divisionsCell Cycle- The series of events involving the growth, replication, and division of a eukaryotic cell
Mitosis- The entire process of cell division including division of the nucleus and the cytoplasmProphase- the first stage of meiosis and mitosis
Centriole- One of two cylindrical cellular structures that are composed of nine triplet microtubules and form the asters during mitosisSpindle- tiny fibers that are seen in cell division; the fibers radiate from two poles and meet at the equator in the middle; "chromosomes are distributed by spindles in mitosis and meiosis"

Metaphase- the stage in mitosis or meiosis in which the duplicated chromosomes line up along the equatorial plate of the spindleAnaphase- the stage in mitosis or meiosis following metaphase in which the daughter chromosomes move away from each other to opposite ends of the cellTelophase- 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- disorder in which some of the body's own cells lose the ability to control growth