PCB 3063 General Genetics Lecture Notes Exam 1 This set of notes is really long If you want to find notes for a specific date ex 1 27 or topic codominance press Ctrl F on your keyboard Command F for Mac users and type in what you want to find It ll search the document for whatever specific word phrase you typed in and save you the time of scrolling through everything Mon 1 6 Gregor Mendel 1866 founder of genetics Discovered inheritance patterns using pea plant Led to Mendelian Inheritance concepts Karyotype organized spread of all of an individual s chromosomes shows genetic abnormalities Ex Down Syndrome karyotype reveals three chromosome 21 s Types of genetics fields cytogenetics molecular genetics eugenics Heredity transmission of genes Trait phenotype expressed genes Domestication human adoption of wild plant animal species Artificial selection human led breeding goes back to around 10 000 20 000 B C Not the same as environmental selection which is natural Ex Dog breeding Can lead to inbreeding which increases the risk of certain diseases Cell division stages Interphase early prophase 1 mid prophase 2 late prophase 3 Development from gametes to embryo Gametogenesis fertilization cleavage gastrulation neurulation organogenesis birth Gametogenesis creation of gametes Zygote fertilized egg cell Cleavage cell splits down middle Blastula hollow many cells Gastrulation gastrula mouth anus tube formed Organogenesis creation of organs Sickle cell anemia genetic disease red blood cell is C shaped rather than a round disc Caused by error in creating proteins Makes malaria less effective More common in African Americans Fruit flies commonly used in genetics experiments due to short lifespan and easy reproduction Genotype genes coding within DNA Phenotype how genes are expressed appearance abilities Wed 1 8 Most information here probably won t be on the exam either Preformationism ideas about genetics from 1600 1850 Homunculus tiny person thought to be tucked inside a sperm Humors Plato Aristotle organs like gall bladder made substances that passed to offspring Spontaneous generation Pasteur living things come from inanimate objects Leave food outside bugs magically appear Fixity of species number of species has always been the same since the Earth was made Epigenesis egg sperm embryo Gamete egg or sperm reproductive cell Germ Plasm theory gametes hold heritable traits Cell theory Schwann Schleiden proposed idea of cell as basic unit of life All organisms made of cells Cells only come from other similar cells or stem cells Natural selection Darwin Wallace Prokaryote no nucleus Eubacteria true bacteria Archaea Eukaryote have nucleus Asexual division one cell two clones Plasma membrane outside of animal cell Nucleus holds DNA Nucleolus inside nucleus makes ribosomes Euchromatin Heterochromatin forms DNA Mitochondria makes energy in animal cells Chloroplasts makes energy in plant cells Mitochondria chloroplasts have dif DNA than that in nucleus Believed that they used to be symbiotic bacteria that got absorbed into the cell Ribosome protein synthesis Centriole organize microtubules Endoplasmic Reticulum ER Chlamydomonas single celled algae has dif mating types 1N cell mating 2N meiosis four 1N offspring cells Multicellular Reproduction 1N cell fertilization 2N zygote S phase two 2N cells mitosis embryo organs Embryo also creates a germ line of cells for the reproductive organs that produce gametes Karyokinesis partitions genetic material Cytokinesis cytoplasm divides volume changes RNA transcripted DNA codes for protein Some code for germ cells RNA removed organism sterile infertile Chromatin DNA RNA proteins Diploid 2N 2 copies of same chromosome skin cells Haploid 1N 1 copy of chromosome sex cells Microtubule stringy fibers in cell attaches to DNA for cell division Kinetochore narrow spot on DNA where microtubule can attach Chromosome tightly wound strand of DNA formed during cell division Humans have 23 pairs chromosomes 1 23 or 46 individual chromosomes Can be either a single strand looks like I or two looks like X Has two arms P arm petite and Q arm larger Sister chromatid half of a chromosome When chromosome is shaped like an X is a single strand I Both sister chromatids held together with cohesin Centromere part where two sister chromatids meet Like the center of an hourglass Checkpoints cell makes sure to see that division is running smoothly helps prevent cancer Spindle assembly checkpoint microtubule spindles made correctly and ready to go If a checkpoint fails cell division stops Apoptosis programmed cell death Happens when a cell is defective and needs to be eliminated Coded for in the genes Helps prevent cancer and other dangerous cell division Cell Cycle G0 G1 check S G2 check Mitosis Interphase non dividing stage anything that isn t mitosis G0 cell grows and matures G1 preparing for mitosis has 1 strand of DNA for a chromosome G1 S checkpoint ready to commit to mitosis S DNA synthesis doubled to prepare for halving the cell later G2 has 2 strands of DNA for a chromosome sister chromatids G2 M checkpoint ready to enter mitosis M Mitosis division for nonreproductive cells Fri 1 10 Stages of Mitosis Prophase Poles Prometaphase Metaphase Middle Anaphase Apart Telophase Cytokinesis Bundle the DNA replicated in S phase into chromosomes centrioles move to poles Nuclear envelope dissolves spindle microtubules grab chromosomes Chromosomes line up on metaphase plate in center of cell Chromosomes split into 2 sister chromatids move to opposite ends of the cell Chromatids unravel nuclear envelope forms again Original 2N cell divides into two 2N daughter cells diploid diploid Meiosis reproductive cell division Original 2N cell divides into four N daughter cells diploid haploid Broken down into Meiosis I and Meiosis II Homologous chromosomes two of the same kind of chromosome chromosome 1 2 3 etc When chromosome is shaped like an X is two of them XX Otherwise look like two strands side by side like in karyotype II Tetrad two homologous chromosomes wind together into single structure Synatonemal complex holds tetrad together Chiasma crossover point on tetrad where chromosomes overlap Recombination gene shuffling happens on chiasma Tetrads formed has four copies of DNA to prepare for the two halvings of the cell Tetrads line up on metaphase plate Homologous chromosomes in tetrads separate into chromosomes alleles separate The 2N parent cell divides into two 2N cells Stages of Meiosis
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