BIOL 2050 1st EditionExam # 4 Study Guide Lectures: 17-22Lecture 17 (March 16)Cell Division What is the purpose of mitosis? Where does it fall in the cell cycle?Mitosis- Two identical daughter cells result with identical genetic informationo Allows for all somatic cells to reproduce and create new cells throughout the body.o Transfers DNA packaged in chromosomes to each cell Each cell has the same number of chromosomes in the resulting stages of mitosisCell Cycle- Interphase: cell growth and the copying of chromosomeso 90% of the cell cycleo Phases G1 Phase S Phase- Where chromosomes are duplicated G2 Phase- Mitotic Phase: small part of the cell cycle where the cell divides o Results in two daughter cellsWhat are the mitotic phases?Mitosis:1.Prophasea. Each duplicated chromosome appears as two identical sister chromatids joined at the centromere.b. Mitotic spindles begin to form2.Prometaphasea. Nuclear envelope fragmentsb. Some chromosomes connect to kinetochores c. Microtubules begin to extend3.Metaphasea. Chromosomes line up at the metaphase plateb. Centrosomes are at opposite sides of the polesc. Kinetochores attach4.Anaphasea. Sister chromatids separate and chromosomes are pulled to opposite sides5.Telophasea. Two daughter nuclei formb. Chromosomes become less condensed6.Cytokinesisa. Division of the cytoplasmLecture 18 (March 18) CancerWhat are the basic concepts of cancer?- Cancer cannot be passed along to offspring- Cancer cells can divide indefinitely- Tumors can be benign or malignanto Benign: tumor stays in one placeo Malignant: the tumor spreads to new tissues and impairs the function of other organs- Treatments include radiation and chemotherapyo Early detection increases survival rates.Lecture 19 (March 20)Meiosis What is meiosis and what are its stages?Meiosis: cell division that results in four haploid cells that are used for sexual reproduction. - Each haploid cell results in half the number of chromosomesPhaseso Prophase 1 Homologous chromosomes pair up Crossing over occurso Metaphase 1 Chromosomes line up by homologous pairso Anaphase 1 Each pair of homologous chromosomes separates Sister chromatids move toward opposite poleso Telophase 1 and Cytokinesis 1 Two haploid cells form Chromosomes still consist of two sister chromatidso Prophase 2 Spindle apparatus formso Metaphase 2 Sister chromatids line up at metaphase plateo Anaphase 2 Sister chromatids separate and move towards opposite poleso Telophase 2 and Cytokinesis 2 Four haploid cells form Each cell has half the number of chromosomes as a somatic cell The four daughter cells are genetically distinct from one another and from the parent cell.What are the main differences between mitosis and meiosis?Mitosis Meiosis- Results in two diploid cells - Results in four haploid cells- Divides once - Divides twice- Cells are genetically identical - Recombination occurs and fourto parent cell unique cells form- Begins with sister chromatids - Homologous chromosomesLecture 20 (March 25)Mendelian Genetics What are some basic terms regarding mendelian genetics?- Incomplete dominance- Monohybrid cross- Dihybrid cross- CodominanceWhat are the different blood types?Typeso Ao Bo ABo O  O blood type is recessive Multiple alleles: more than one allele codes for one traitWhat are sex-linked disorders and why are males more susceptible?Sex-Linked Disorder: disorders resulting from deformities on the X chromosome.Examples: Colored blindness XXY: Klinefelter’s syndrome X: Turner’s syndrome XYYo Men are more susceptible to sex-linked disorders because they only have one Xchromosome and women have two. If there is a problem on one X chromosome, women can refer to the other. Men, however, only have one to work with. Lecture 21 (March 27)How does one’s sex determine different traits?- Presence of SRY gene on Y chromosome makes a male- Men are more prone to sex-linked disorders because males only have one X chromosome and women have two.- Down Syndrome is more prone to children with older mothersWhat are polygenic traits and what is an example?Polygenic traits are traits that are determined by more than one gene.Example: Skin