Study guide BIO 2 FINAL No LectureBe able to identify dependent and independent variables in both observational tests and experimentsKnow how to cite a scientific paper in the text of something you write and then how to write out the citation at the end.- Dependent variable: Measure of the independent variable. It depends on the independent variable. What you are testing.- Independent variable: Variable you change.- Ex: Experiment looking @ growth of trees in different lightingInd: Where you put the tree. (dark room or outside)Dep: How well the tree grows (what you want to know)Write out the citation according to the following format.Name(s) of authors. Year of Publication. Title of Article. Journal Name Volume Number: Page numbers.For exampleDixon, K. 1999. The end of the universe will happen next Tuesday. Journal of Unlikely Phenomena 12: 201-207.Lecture 2 (320-322, 228-231, 232-233, 231-243)Know that cells grow, synthesize DNA, and divide in a cycle with distinct phases- Interphaseo G1-First Gap-The cell growso S-Synthesis- Chromosomes are duplicatedo G2-Completes preparation for cell division- Mitosiso Prophase Chromatin become more tightly coiled Nucleoli disappear Sister chromatids appear Mitotic spindle begins to form Centrosomes move away from each othero Prometaphase- Microtubules begin to attach at the kinetochoreo Metaphase- Chromosomes come to the metaphase plateo Anaphase Shortest stage Pulls apart the sister chromatids to opposite sides of the cello Telophase and cytokinesis Cleavage of the cell and eventual formation of 2 daughter cellsUnderstand that the cell cycle is controlled by molecules present in the cytoplasm that regulate movement of the cycle past ‘checkpoints’o 3 major checkpoints, checkpoints are found in G1,G2, and M phaseso G1-“restriction point” seems to be the most important.o If cells go ahead G1 it will usually complete G1,S,G2 and Mo If not it will go into the G0 phase. Most cells of the human body are in this phase.Lecture 3 (28.6, 31.1, 738-741, 746-750,755-759,40.1)Understand that meristems are sites of cell division and that development occurs after cell divisionLecture 4 (18.1-18.3)Control of transcription occurs through the binding of activators or repressors to special sites on the DNA• Operator- Switch that is a segment of DNA. “On-off”• Operon- The DNA required for enzyme production.• Operon can be switched off by a protein called a repressor.• Repressor- binds to the operator blocks attachment of the RNA polymerase, preventing transcription.• The repressor is the protein product of a regulatory gene.• Activator- Protein that binds to DNA and stimulates transcription of a gene.Know that gene expression in eukaryotes can be controlled at multiple stages during transcription and translation The differences between cell types are not due to different genes being present but to differential gene expression, the expression of different genes by cells with the same genome. The transcription factors of a cell must locate the right genes at the right time. Three main common featureso Separate coding region for regulatory geneo Regulatory gene codes for repressor that binds to operator region at start of coding regiono “Signal molecule” interacts with repressor to switch on or off Control of gene expression in Eukaryotes can occur at:o Chromatin modification- DNA packagingo Transcription, RNA modification, RNA transporto Translationo Post translation- protein modification, degradation, transportKnow that modification of histone structure can affect transcription Histones- Proteins around which the DNA is wrapped in nucleosomes. Histone acetylation- Acetyle groups attach to lysines in histone tails. This may promote the initiation of transcription not only by remodeling chromatin structure, but also by binding to andthus “recruiting” components of the transcription machinery. Other chemical groups, such as methyl and phosphate, can be reversibly attached to amino acids in histone tails. Addition of methyl to histone can promote condensation of the chromatin,(making it harder to be transcribed) while addition of a phosphate to an amino acid next to a methylated amino acid can have the opposite effect. DNA methylation seems to be essential for the long-term inactivation of genes. Know that enhancers and transcription factors can affect transcription• The are some control elements on the DNA• Proximal control elements are close to the promoter.• The distal control elements are called enhancers.• A given gene may have multiple enhancers, each active at a different time or in a different cell type or location.• Each enhancer, however, is generally associated with only that gene.• In eukaryotes, the rate of gene expression can be strongly increased or decreased by the bindingof specific transcription factors, either activators or repressors, to the control elements of enhancers. Lecture 5 (18.4,18.5,21.6)Cell differentiation occurs during early development because of different concentrations of cytoplasmic Determinants• Differentiation- process by which cells become specialized in structure and function.• Morphogenesis- processes that give an organism its shape• One important source of information earl in development is the egg’s cytoplasm, which containsboth RNA and proteins encoded by the mother’s DNA.• Substances are not distributed evenly in the unfertilized egg, and this has profound impact on the development on the future embryo.• Cytoplasmic determinants- Maternal substances in the egg that influence the course of early development.• This uneven cell divides and there are different concentrations of cytoplasmic determinants in the new cells and this creates differentiation. Lecture 6 (47.1,32.3)Understand that polyspermy is blocked by 2 mechanisms in sea urchins and why blocking multiple fertilizations is important. Stages of sea urchin fertilization1. Contact/recognition Sperm releases enzymes that digest eggs outer coat ***Acrosomal reaction:- Sperm ejects an acrosomal process- Recognition protein receptors in egg cell membrane bind to acrosomal-process proteins- Egg receptors and sperm acrosomal proteins are species-specific*2. Acrosomal Reaction Egg becomes depolarized ****Results in FAST BLOCK of polyspermy: occurs within 1-3 seconds of contact but is temporary: last only about 1 minute3. Cell
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