BIOL 425 1st EditionExam # 2 Study Guide Lectures: 8-10 and 22-25Chapter 8 (Sexual Reproduction and Heredity)- Meiosis: The process of nuclear division in which the chromosome number is reduced from the diploid (2n) to the haploid (n) number. In plants, meiosis occurs during the production of spores, known as meiospores, in flowers cones, etc. Meiosis occurs in two phases (I and II). Prophase I begins the process, the chromosomes become visible as elongated threads, homologous chromosomes come together in pairs, the pairs coil around each other, and the paired chromosomes become very short. During Metaphase I, the paired chromosomes move into position on the metaphase plate, with their centromeres evenly distributed on either side of the equatorial plane of the spindle. Next, Anaphase I the paired chromosomes separate and move to opposite poles. Phase II begins with Metaphase II where the chromosomes are lined up at the equatorial plane, with their centromeres lying on the plane. Anaphase II the centromeres separated and the chromatids separate and move toward opposite poles of the spindle. Lastly, Telophase II the chromosomes have completed their migration. Four new nuclei, each with the same haploid number of chromosomes, are formed.- Gamete: a cell that unites with another gamete to produce a diploid zygote, which may then divide, either meiotically or mitotically. - Crossing-over: the exchange of corresponding segments of genetic material between the chromatids of homologous chromosomes at meiosis.- Genetic Recobination:- Mutations: any change in the hereditary makeup of an organism. These can occur as gene or chromosome mutations. Mutation provides the variability among organisms that is the raw material for evolution. Types include point mutations, deletions, duplications, inversions, translocations and changes in chromosome number- Transposons: a DNA sequence that carries out one or more genes and is flanked by sequences of nucleotides that confer the ability to move from one DNA molecule to another.- Aneuploidy: a chromosomal aberration in which the chromosome number differs slightly from the normal chromosome number for the species.- Polyploidy: referring to an organism, tissue or cell with more than two complete sets of chromosomes.- Incomplete Dominance: refers to a genetic situation in which one allele does not completely dominate another allele, and therefore results in a new phenotype.- Epistasic: describing a gene whose action modifies the phenotype expression of a gene at another locus.- Polygenetic Inheritance: Polygenic inheritance refers to the kind of inheritance in which the trait is produced from the cumulative effects of many genes in contrast to monogenic inheritance wherein the trait results from the expression of one gene (or onegene pair). In humans, height, weight, and skin color are examples of polygenic inheritance, which does not follow a Mendelian pattern of inheritance.- Pleiotropy: The capacity of a gene to affect more than one phenotypic characteristic.- Cytoplasmic Inheritance: The inheritance of characteristics under the control of gene located in plastids and mitochondria.- Asexual reproduction: Results in progeny that are identical to their single parent. Unlike sexual reproduction, meiosis, fertilization and recombination do not occur in asexual reproduction. Sexual reproduction results in diversity and asexual reproduction does not.Chapter 9 (The Chemistry of Heredity and Gene Expression)- Operon: in the bacterial chromosome, a segment of DNA consisting of a promoter, operator and a group of adjacent structural genes.- Promoter: A specific segment of DNA to which RNA polymerase attaches to initiate transcription of mRNA from an operon.- Gene Regulation: the process of turning genes on and off. During early development, cells begin to take on specific functions. Gene regulation ensures that the appropriate genes are expressed at the proper times. Gene regulation can also help an organism respond to its environment.- Structural Genes: Any gene that codes for a protein; as opposed to a regulatory gene.- Transcription of each gene in eukaryotes is regulated separately, and each gene produces an RNA transcript containing the encoded information for a single product. RNA transcripts are processed in the nucleus to produce the mature mRNA molecules that move from the nucleus to the cytoplasm. This processing includes the removal of introns and the splicing together of exons.Chapter 10 (Recombinant DNA Technology, Plant Biotechnology, Genomics)- Recombinant DNA: DNA formed either naturally or in the laboratory by the joining of segments of DNA from different sources.- Restriction Enzyme: an enzyme produced chiefly by certain bacteria, having the property of cleaving DNA molecules at or near a specific sequence of bases.- Plant Biotechnology: a set of techniques used to adapt plants for specific needs or opportunities.- Tissue Culture: the growth in an artificial medium of cells derived from living tissue.- Micropropagation: the propagation of plants by growing plantlets in tissue culture and then planting them out.- Ti Plasmid: A circular plasmid of Agrobacterium that enables the bacterium to infect plant cells and produce a tumor; a powerful tool in biotechnology in the transfer of foreign genes into plant genomes.- Transgenic Plants: plants whose genome contains DNA, from the same or a different species, that has been modified by the methods of genetic engineering.- Genetic engineering technology is based on the ability to cut DNA molecules precisely into specific pieces and to combine those pieces to produce new combinations. The Ti plasmids of Agrobacterium tumefaciens, which induces the formation of crown-gall tumors, is being used as a vector for introducing foreign genes into a plant’s genes. The transgenic plant then transmits the foreign genes to its progeny. Through the use of selective markers and reporter genes, it is possible to determine whether genes carried by the plasmid vector have been successfully transferred to the plant cells and are being expressed. Note that genetic engineering is being used to confer resistance to insects and tolerance to herbicides.Chapter 11 (Process of Evolution)- Gene flow: In population genetics, gene flow (also known as gene migration) is the transfer of alleles or genes from one population to another. Migration into or out of a population may be responsible for a marked change in allele