Unit 1 Concepts Lecture 1 Independent variable variable in an experiment that is manipulated by researcher Dependent variable the result of the manipulated variable For example let s say you were doing an experiment on how different amounts of studying effects test scores The independent variable would be the amount of time spent studying and the test score would be the dependent variable To cite a scientific paper within something you write Author s Last Name Year of Publication Pages You re Referencing To cite at the end Name s of authors Year of Publication Title of Article Journal Name Volume Number Page numbers Lecture 2 Know that cells grow synthesize DNA and divide in a cycle with distinct phases Understand that the cell cycle is controlled by molecules present in the cytoplasm that regulate movement of the cycle past checkpoints Cell cycle life of a cell from the time it is formed from a dividing parent to its own division into 2 daughter cells Can be divided into interphase where it spends most of its life and M mitotic phase During interphase cells go through the G1 phase just growth of the cell followed by the S phase in which DNA is duplicated and then the G2 phase more growth During the M phase very short in comparison to interphase the cell undergoes mitosis division of the genetic material in the nucleus and cytokinesis division of the cytoplasm The cell only goes into the next phase based on the concentration of certain molecules these serve as a checkpoint If the molecules are not present the cell is not ready for the next phase Lecture 3 Understand that meristems are sites of cell division and that development occurs after cell division Meristems tissue in plants in which cell division occurs often Development occurs after cell division has produced new daughter cells Development determines what type of cell and thus what role the cell will play in the plant the new cells will become Lecture 4 Control of transcription occurs through the binding of activators or repressors to special sites on the DNA Know that gene expression in eukaryotes can be controlled at multiple stages during transcription and translation Know that modification of histone structure can affect transcription Know that enhancers and transcription factors can affect transcription Transcription is the synthesis of RNA using information from the DNA The binding of certain molecules may either activate or repress a certain area within DNA to be transcribed or not transcribed activators and repressors Before the RNA is translated both ends of the RNA are modified the 5 end receives a 5 cap and the 3 end receives a poly A tail Many portions of the RNA do not code for anything and are removed introns Certain stretches of RNA may be removed or kept depending on what gene products are needed in the cell alternative RNA splicing Histones are proteins with DNA coiled around them Acetylation of histone tails promotes transcription Adding methyl groups methylation prevents transcription of a particular segment of DNA Certain proteins may bind to DNA segments to initiate the binding of RNA polymerase and thus transcription enhancers and transcription factors Lecture 5 Cell differentiation occurs during early development because of different concentrations of cytoplasmic determinants Cell differentiation is the process by which cells become specialized in structure and function for example stomach cells do not look function like kidney cells This differentiation is caused by different concentrations of cytoplasmic determinants maternal substances in the egg Lecture 6 Understand that polyspermy is blocked by 2 mechanisms in sea urchins and why blocking multiple fertilizations is important Know that cleavage has different patterns in different organisms and what those patterns are In fast block in sea urchin fertilization when the tip of the acrosomes comes into contact with the plasma membrane of the egg it releases hydrolytic enzymes These enzymes digest the jelly coat surrounding the egg allowing the sperm to penetrate the coat Specific proteins on the surface of the acrosome of the sperm a coating around the anterior part of the sperm cell bind to specific receptor proteins on the egg s plasma membrane As the sperm continues into the egg and its nucleus fuses with that of the egg sodium ions diffuse into the egg and cause depolarization which causes a decrease in the membrane potential preventing any additional sperm molecules from penetrating the egg as well Slow block to polyspermy occurs after fertilization Vesicles called cortical granules beneath the egg s plasma membrane fuse with the plasma membrane their contents being released into the space between the plasma membrane and the surrounding vitelline layer A vitelline structure is a structure formed by the extracellular matrix of the egg The contents of the granules include macromolecules and some enzymes that trigger a cortical reaction which causes the vitelline layer to be lifted away from the egg and also causes a hardening of the layer surrounding the egg into a protective fertilization envelope This hardening in combination with other changes in the egg s surface prevents additional sperm from penetrating the egg Cleavage may be spiral planes of cell division that transform a zygote into a ball of cells are diagonal to the vertical axis of the embryo as in protostomes or may be radial planes of cell division that transform zygote are either parallel or perpendicular to vertical axis of embryo as in deuterostomes Lecture 7 Know that gastrulation produces three basic types of embryonic cells Understand that the archenteron is the embryonic gut forms as a result of gastrulation Gastrulation produces the ectoderm mesoderm and endoderm Ectoderm skin epidermis nervous system skull Mesoderm skeletal circulatory reproductive and excretory systems muscles notochord Endoderm thymus thyroid pancreas liver epithelial lining of digestive tract respiratory reproductive and excretory systems Lecture 8 Understand that the position of regions of the embryo relative to one another provides information that determines the formation of organs Know the examples from neurulation notochord stimulates the formation of the neural plate neural tube stimulates neural crest cells Notochord longitudinal flexible rod made of tightly packed mesodermal cells that run along anterior posterior axis of a chordate in the dorsal part of the body The notochord stimulates
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