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SIU PLB 115 - Exam 1 Study Guide

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PLB 115 1st EditionExam # 1 Study Guide Lectures: 1 - 5Lecture 1 (January 22nd) - What is Biology?Biology: The science that deals with lifeScience: Process used to solve problems & understand natural events- Scientific method: gaining information of the world byo Asking questions & generating possible solutions/answerso Continuous testing & re-checking to make sure solutions are accurate Steps: Observation, questioning, forming hypotheses, testing hypotheses, evaluation of information, constant review & repetition of tests by peersObservation: Thoughtful & careful recognition of event or fact.Hypothesis: Logical, testable, consider current information on topicTesting methods: Researching & recording up-to-date information, experimentation, observations about nature Experiment: Re-creation of occurrence testing hypothesis for support or rejection- Only 1 variable manipulated (changed) & all others stay same (kept constant/controlled) Independent variable: Variable that changes/is changedDependent variable: Variable that changes in response to independent variableHypotheses rejected & revised or supported Hypothesis support after much re-creation and scrutiny= TheoryTheory: Logical, widely accepted statement about a fundamental scientific concept that can be used to predict facts through deductive reasoning ** Not set in stone, can changeScientific Law: Uniform, constant fact of nature to describe natural occurrencesPseudoscience: “Fake”/deceptive practice using scientific language to convince people into thinking that it has scientific validityLecture 2 (January 27th)- The Origin of LifeCharacteristics of Living Things- Metabolic processes: Obtain & store energy in chemical bonds in of ingested nutrients - Generative processes :Grow by increasing the number of cells, reproduce sexually/asexually- Responsive processes: Organisms react to changes in their environment- Irritability: ability to recognize that something in its surroundings has changed (a stimulus) & quickly respond- Evolution: Changes (genetic & appearance) in a population over time- Control processes :Carry out metabolic processes in correct order- Coordination: Enzymes coordinate metabolic reactions- Regulation: Enzymes regulated in order to maintain homeostasis- Unique structural organization: Organisms made of (many) cellsOrganization in Biology: Organ system, Organ, Tissue, Cell, Molecules, Atoms, Biosphere, Ecosystem, Communities, Population, OrganismTheories about Origin of Life- Spontaneous Generation: Living things came from non-living things o Needham experiment: Mutton broth in containers sealed with cork became cloudy with microorganisms yet sealed & boiled- Biogenesis: Living things can only come from pre-existing living thingso Spallazani experiment: Same- with sealed containers- those that had no bacteria- & containers with broken glass did have bacteriaPasteur: Same experiment but used flasks with long & curved necks (allow oxygen but not bacteria in)- Bacteria only in flasks with broken necksTheories of Origin of Life on Earth•Panspermia: Life came from outside earth, transported to earth•Abiogenesis: Life came from chemical reactions of inorganic matter that created organic moleculesEarth’s Early Atmosphere•Thermonuclear reactions made the earth HOT, creating molten core encased by a thin outer crust as Earth cooled- Cooling allowed water to condense & fall as rain to form bodies of waterFormation of Cells•Early cells had to form/have: Complex organic molecules from simple inorganic ones, genetic material that self-replicated, enzymes, membranes to separate genetic material & organic molecules from surroundings, method to obtain energyRNA as Original Genetic Material•DNA too complicated & requires enzymes not yet present in early Earth- Evidence for RNA: Some viruses use RNA as their genetic material, mutate, replicate themselves, & serve as catalysts (ribozymes) for some reactionsDevelopment of Membranes- Oparin’s suggestion: Membranes= collection of organic molecules surrounded by water (coacervates)- Hypothesis #2: Cells began as collections of organic molecules with a double-layered boundary - Hypothesis #3: Membranes formed from lipids interacting with waterLecture 3 (January 29th)- Cells & their ComponentsHeterotrophs: Obtain energy from organic molecules in environment to build new organic moleculesAutotrophs: Use external energy source (like sunlight) to make organic molecules from inorganicmatterHeterotroph Hypothesis: 1st organisms on Earth anaerobic. Heterotrophs living off organic molecules in ocean. Organisms reproduced & depleted supply of organic molecules. Mutation produced organisms that could use inorganic molecules to make organic ones (autotrophs).Autotroph Hypothesis: 1st organisms were autotrophs that used energy released from inorganicchemical reactions to make organic molecules. After exhaustion of raw inorganic molecules, mutation led to evolution of heterotroph creatures from autotrophs.Development of an Oxidizing Atmosphere•Bacteria, in photosynthesis, released oxygen as waste productFirst Cells•Prokaryotic (Bacteria)- Eukaryotic (Animals) cells evolved from ProkaryotesEndosymbiotic Theory• Prokaryotes came together to become one Eukaryote- Bigger prokaryote swallowed smaller one (for protection) & smaller prokaryote provided larger prokaryote with extra energy: How organelles originated Prokaryotes vs EukaryotesProkaryotic: Simple, small , lack nucleus & most organellesEukaryotic: More complex- Has nucleus, many of organelles, bigger than prokaryotes Cell MembranesThin sheets of phospholipids (phosphorous heads + lipid tails) & proteins that separates the contents of the cell from the external environment- Functions: Metabolic activities, moving molecules across, identification to other cells,attachment sites for other cellso **Organelles with Cell Membranes: Endoplasmic reticulum, Golgi apparatus, Lysosomes, Peroxisomes, Vacuoles, Mitochondrion, Chloroplast, Nucleus (double)Fluid-mosaic model• 2 phospholipid layers, Oily consistency, Materials move laterally within the bilayer, “Mosaic”= Proteins embedded within phospholipid bilayerMembrane Proteins• On surface, embedded in, protrude out- Functions: Transport molecules across membrane, provide attachment points for other cells, identity tags for cells (to recognize as own)Nucleus • Chromatin: (DNA+ Proteins) later condensed into chromosomes during cell division• Double membrane


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