GENETICS EXAM 1 Chapter 1 Introduction o Gene a unit of heredity blueprints A sequence of DNA that contains the instructions for production of a protein variant of a gene formed by o Allele mutation Only mutation in the sperm or egg cells are passed onto the next generation Any change in the sequence of DNA May be positive negative or neutral but mostly negative discrete units that DNA is o Chromosome packaged One from mom one from dad come in pairs Composed of DNA and protein histones Found in the nucleus of a cell 46 total chromosomes 23 pairs o Humans have 22 pairs of autosomes proteins that do not determine sex o Humans have 1 pair of sex chromosomes Females Males XY XX o Genotype vs Phenotype Genotype Phenotype unique combination of alleles that people carry structure can be expressed even with one copy visible trait physical Chapter 2 Cells and Mitosis Basic components of the typical human cell o Cell Membrane phospholipid bilayer Amphipathic One end is hydrophobic one is hydrophilic houses genetic material DNA o Nucleus Membrane of nucleus is nuclear envelope with nuclear pores that things travel in and out of Protein shape determines that function of that protein o Endoplasmic Reticulum factory synthesizes Smooth ER lipids hormones Rough ER proteins synthesizes ribosomes o Mitochondria o Golgi Apparatus powerplant of the cell Turns glucose into ATP for energy Lysosomes destroy intracellular Packages and sends out UPS of the cell o Cytoskeleton made up of protein 3 debris kinds Microfilaments actin Intermediate Microtubules Basic components of the cell cycle o Interphase majority of the time the cell is not physically dividing or it is preparing to divide chromosomes are uncondensed G1 phase cell doing its normal thing Prepares for DNA replication and making proteins Can exit the cell and go to G0 phase G0 phase cell cycle removes itself from the Cell does not divide or replicate Now has three options 1 Proceed to cell division G2 phase 2 Remain specialized 3 Cell death DNA is synthesized and S phase condensed and chromosomes replicate G2 phase prepares for mitosis o Chromatids of chromosomal material two identical replicated strands Chromosome is a pair of sister One side of the chromosome is the chromatids chromatid o Centromere holds the chromosomes attach GENETICS EXAM 1 o Mitosis makes two identical copies cell division in somatic cells one cell Prophase DNA is condensed into chromosome spindles Centrioles appear Nuclear envelope begins to degrade Metaphase chromosomes align and attach to the spindle fibers at the centromere Anaphase centromeres part and the chromatids seperate Telophase cell begins to divide into two spindle dissembles Nuclear envelope re forms o Cytokinesis actual splitting of the cells Between the G1 and S phase stand by G0 phase when the cell can either proceed to division or cell death apoptosis Apoptosis programmed cell death Protein death receptors which trigger and activate killer enzymes casapses Checkpoints 3 points to check chromosome 1 DNA damage checkpoint cycle until DNA can be fixed 2 Apoptosis checkpoint death in G2 phase If surviving accumulates cell division goes on inhibits cell programmed cell 3 Spindle Assembly checkpoint spindle built Are chromosomes aligned in the middle is Totipotent vs pluripotent stem cells o Totipotent stem cells that make anything as long as correct genes are activated All genes at a certain point are toti differentiation Make a lot of specialized cells Pluri plural not all but many stem cells through o Pluripotent Chapter 3 Meiosis and Development Diploid vs Haploid cell o Diploid type two copies of each chromosome o Haploid one type of each chromosome Meiosis 1 Reduction Division o Prophase I Early homologs pair chromosomes that have been copied Crossing over occurs Late chromosomes condense and spindle forms Nuclear envelope breaks down o Metaphase I homolog pairs align along the center of the cell o Anaphase I homologs separate and move to opposite poles Sister chromatids remain attached at their centromeres o Telophase I ear membrane reforms and spindle disappears Cytokinesis divides cell End of Meiosis 1 2 haploid cells Meiosis 2 The equational division o Prophase 2 Telophase 2 o Differences no crossing over o Anaphase 2 Sister chromatids separate Centromeres divide End of Meiosis 2 4 haploid cells each containing one copy of each chromosome and one allele of each gene Two different kinds of gametogenesis 1 Spermatogenesis males Start with diploid Spermatogonium Undergo mitosis and sexual maturity then undergoes meiosis 1 and 2 finally forms haploid sperm cells o 3 parts of a sperm cell 1 Acrosome head of sperm contains enzymes for fertilization and entry of sperm into egg 2 Midpeice has spiral mitochondria engine filled with ATP to fuel tail 3 Tail movement flagellum 2 Oogenesis females Start with diploid oogenium GENETICS EXAM 1 During Fertilization Undergoes mitosis and forms primary oocyte Goes through meiosis 1 where it forms the polar body and secondary oocyte To continue Meiosis 1 you need FSH and LH If fertilization occurs Secondary oocyte goes through meiosis 2 and forms ovum The egg is covered by non egg cells called corona radiate and contain a protective barrier called zona pellucida During the acrosomal reaction enzymes change the shape of this so no other sperms can get through Sperm releases its genome while egg finished meiosis 2 o Cleavage Zygote undergoes Mitotic cell division a morula 16 64 cells Cells are called blastomeres developing embryo becomes a blastocyst a hollow ball of cells o Blastocyst Inner cell mass develops into the embryo Other cells become the extraembryonic membrane important for implantation and cell growth o Gastulation Primary germ layers form Cells differentiate By 10 weeks the placenta has developed o 3 primary germ layers 1 Ectoderm outer most layer Makes epidermis nervous system pigmented cells and face skeleton middle layer Makes dermis most muscle and skeleton gonads and kidneys 2 Mesoderm 3 Endoderm inner layer Digestive tract liver lungs pancreas bladder Chapter 4 Mendelian Genetics o Gregor Mendel Australian monk Studied pea plants Father of modern genetics Proposed that inheritance was caused by discrete factors called genes and had alternate forms called alleles Inherited in pairs two copies of the same breed two copies of different Heterozygous Homozygous true breed non true 1 Monohybrid cross Experiments trait Phenotype 3 1 Genotype 1 2 1