BIOL 201 Study Guide 1
BIOL 201 Study Guide 1 BIOL 201-015
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This 12 page Study Guide was uploaded by Kayla Wisotzkey on Saturday September 17, 2016. The Study Guide belongs to BIOL 201-015 at Towson University taught by Cheryl D. Warren in Fall 2016. Since its upload, it has received 66 views. For similar materials see Intro to Cell Biol & Genetics in Biology at Towson University.
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Date Created: 09/17/16
Kayla Wisotzkey Chapter 1 The seven characteristics of living systems: 1) Cellular organization: All organisms have one or more cells, which carry out basic activities of living; cells contain a membrane 2) Ordered complexity: All living things are both complex and highly ordered 3) Sensitivity: All organisms respond to stimuli; aka. a plant moving to face the sun 4) Growth, development, and reproduction: All organisms grow, reproduce, and pass on hereditary information (Note: viruses are not living because they cannot reproduce without a host cell) 5) Energy utilization: All organisms take in energy and perform work 6) Homeostasis: All organisms maintain constant internal conditions 7) Evolutionary adaptation: organisms evolve and adapt to their environment to survive Biological hierarchy smallest to largest: atoms, molecules, organelles, cells, tissues, organs, organ systems, population, species, community, ecosystem, biosphere Ecosystem: the population plus the environment Biosphere: the entire planet Emergent properties: novel properties arising from the way in which components interact; CANNOT be deduced solely from the knowledge of the individual components. Basically, you have to look at the bigger picture and not just individual pieces of it. Types of science 1) Discovery science: making new discoveries about the world/universe 2) Correlative science: using statistics and relationships to find out things that you can’t ethically test 3) Experimental science: taking an observation and forming a hypothesis, then testing that hypothesis to form a conclusion. Types of reasoning Deductive reasoning: applies general principles to predict specific results; it is the reasoning of mathematics and philosophy, and it is used to test the validity of general ideas in all branches of knowledge Inductive reasoning: uses specific observations to construct general scientific principles; leads to generalizations which can then be tested Factors of an experiment independent variable: the variable that you alter for the experiment dependent variable: the variable that depends on the value of the independent variable control experiment: the variable is left unaltered theory: 1) a proposed explanation for some natural phenomenon, often based on a general principle, 2) a body of interconnected concepts, supported by reasoning and evidence, that explains facts of study. Note: theories are NOT proven!! Charles Darwin observed that although every organism has the potential to produce more offspring than can survive, only a limited number actually do survive and produce offspring Natural selection: individuals possessing advantageous traits are more likely to survive and reproduce than those with less advantageous traits the characteristics of similar species varied from place to place; lineages change gradually as species migrate from one area to another Cells and DNA cell theory: All living organisms consist of cells, and all cells come from preexisting cells and contain DNA Each DNA molecule is formed from 2 nucleotides wrapped around each other gene: unit of information made up of thousands of nucleotides genome: entire set of DNA instructions that specifies a cell ALL organisms alive today have descended from a simple cellular creature cells process information by sensing the environment through proteins in their membranes, which is transmitted across the cell membrane to chemical pathways, which can react and change the cell function Homologous: have the same origin but differ in structure and function Analogous: have similar functions but different origins Three domains: 1) Bacteria: singlecelled 2) Archaea: singlecelled 3) Eukarya: single or multiplecelled Four Kingdoms: 1) Protista: unicellular eukaryotes, multicellular algae 2) Plantae: organisms with cellulose, use photosynthesis to make food 3) Fungi: have cell walls of chitin, obtain energy by secreting digestive enzymes and then absorbing the products they release from the environment 4) Animalia: lack cell walls and obtain energy by ingestion and digestion More important information: prokaryotes: singlecelled, lack a nucleus and other organelles, the DNA is stored in the nucleoid, the cell wall provides shape and protection eukaryote: single or multiplecelled, contains a nucleus (stores DNA) and other organelles Chapter 2 The Nature of Molecules and the Properties of Water Subatomic particles Matter: has mass and occupies space, is composed of atoms Nucleus: contains protons (positive charge) and neutrons (no charge). Electrons(negative charge) are found in the orbitals surrounding the nucleus MOST of an atom’s volume is empty space Mass number: the number of protons PLUS the number of neutrons Atomic number: the number of protons (this identifies the element) Valence number: the number of unpaired electrons Octet rule: All atoms want to fill their outer circle with electrons (Max. 8 electrons) Electrons are attracted to the positive nucleus, so the farther away the electron is from the nucleus, the higher its potential energy is Isotopes: atoms of a single element that possess different numbers of neutrons Bonding Ion: Any atom with a charge Ionic bonds: when an atom gives away or gains an electron. These bonds form: a. cation: has a positive charge, caused by the loss of an electron b. anion: has a negative charge, caused by the gain of an electron covalent bonds: when one or more pairs of electrons are shared between 2 atoms, very STRONG bond a. single covalent bond: one pair of electrons are shared; free rotation and flexibility b. double covalent bond: two pairs of electrons are shared; more versatility, more rigid, no rotation c. triple covalent bond: three pairs of electrons are shared, extremely rigid Electronegativity: an atom’s affinity for electrons UPPER RIGHT hand side of the periodic table are more electronegative nonpolar covalent bonds: equal sharing of electrons, equal electronegativity polar covalent bonds: unequal sharing of electrons; the more electronegative atoms hold the electrons more tightly and will have a partial negative charge, and the other atom will have a partial positive charge Hydrogen bonding: covalent bond between Hydrogen and a strongly electronegative atom and another strongly electronegative atom To increase a reaction: apply heat, add more reactants, and add catalysts Water’s abilities Hydrogen bonds: Water can form hydrogen bonds, weak chemical associations that form between partially negative Oxygen atoms and partially positive Hydrogen atoms of two different water molecules Stability: water molecules are stable because they satisfy the octet rule and have no unpaired electrons, and they carry out no electrical charge Cohesion: water is attracted to itself and sticks together; this quality is responsible for water being a liquid and its surface tension Adhesion: water sticks to any substance with which it can form hydrogen bonds, causes the meniscus that occurs in graduated cylinders Capillary action: the adhesion of water to a glass surface is stronger than the force of gravity Properties of water 1) High specific heat: the amount of heat that must be absorbed or lost for one gram of that substance to change its temperature by 1C Water heats up more slowly and holds its temperature longer than any other compound 2) High heat of vaporization: the amount of energy needed to change one gram of a substance from a liquid to a gas As water changes from a liquid to a gas it requires energy to break the hydrogen bonds 3) Water is a solvent: something that dissolves other substances Solute: the substance that dissolves in the solvent (salt, sugar, etc.) Water organizes nonpolar molecules: when nonpolar molecules are placed in water, the water molecules exclude them and make them clump together Hydrophobic: nonpolar molecules, don’t bond with water, “waterfearing” Hydrophilic: polar molecules (ions), bond with water, “waterloving” 4) Water can form ions ionization: covalent bonds of a water molecule sometimes break, and a proton dissociates from the molecule. It breaks into a Hydrogen ion and a Hydroxide ion 5) Ice is less dense than water because the hydrogen bonds in ice spread the water molecules far apart; this causes water to freeze from the top down At low temperatures, water molecules are locked into a crystallike lattice of hydrogen bonds, forming ice Acids and bases acid: any substance that dissociates in water to increase the Hydrogen ion level and LOWER THE pH level base: a substance that combines with Hydrogen when dissolved in water, lowering the Hydrogen ion level and RAISING THE pH level buffer: a substance that resists changes in pH; it acts by releasing hydrogen ions when a base is added and absorbing hydrogen atoms when an acid is added…the effect is keeping the Hydrogen level constant Acidosis: human blood’s pH goes from 7.4 to 7.1, could be deadly if not treated Alkalosis: human blood’s pH goes from 7.4 to 7.7, deadly if not treated pH scale goes from 0 to 14, 0 being acidic and 14 being basic + pH= log[H ] Chapter 3 Carbon: the building blocks of life carbon atoms can form up to 4 covalent bonds hydrocarbons: molecules consisting of just Hydrogen and Carbon; store a lot of energy, make good fuels, and are nonpolar functional group: a molecular group attached to a hydrocarbon that confers chemical properties or relativities (Ex. Hydroxyl…OH) isomer: one of a group of molecules identical in atomic composition, but differing in structural arrangement (Ex. Glucose and Fructose) 1. Structural isomers: different in the structural order 2. Stereoisomers: different in how the groups that are attracted to the skeleton are arranged in space, but same order chiral compounds: characterized by their effect on polarized light 1. Dextrorotatory: moves light to the right 2. Levorotatory: moves light to the left Polymer: long molecule built by linking together a large number of smaller units called monomers Two reactions involving polymers: 1. Dehydration reaction: to form a covalent bond between two monomers, an OH group is removed from one monomer and an H atom is removed from the other(removal of H 2), MONOMERSPOLYMERS 2. Hydrolysis: to dissemble polymers into monomers, a molecule of water is added…an H atom is added to one subunit and an OH group is added to the other, POLYMERSMONOMERS Carbohydrates: all contain carbon, hydrogen, and oxygen in a 1:2:1 ratio the building blocks of carbohydrates are sugars contain many carbonhydrogen bonds which release energy when oxidation occurs; good energy storers monosaccharides: simplest carb, classified by the location of the carbonyl group glucose: best 6carbon monosaccharide for energy storage b/c it has 6 CH bonds disaccharides: used for sugar transport and energy storage, made my linking two monosaccharides together, hold energy well b/c enzymes cannot break their bonds polysaccharides: long polymers made of many monosaccharides that have gone through dehydration synthesis, main polysaccharides include: 1. Starch: energy storage in plants 2. Cellulose: structural support in plants, make up cell walls 3. Chitin: structural support in fungi and arthropods 4. Glycogen: energy storage in animals Nucleic Acids: serve as templates for producing exact copies of themselves, allow genetic materials to be preserved during cell division and reproduction the building blocks of nucleic acids are nucleotides The covalent bonds between two nucleotides are called phosphodiester bonds nucleotide structure: phosphate group, 5 carbon sugar (either ribose (RNA) or deoxyribose (DNA)), and a nitrogenous base The two main types are DNA and RNA: 1. RNA: carries genetic information, helps with protein synthesis and gene expression messenger RNA (mRNA) consists of singlestranded portions of DNA, which is the blueprint for the amino acids of proteins ribosomal RNA (rRNA) helps build the structure of ribosomes transport RNA (tRNA) transports the amino acids to the cite of protein synthesis There are two types of nitrogenous bases found in nucleotides: a) Purines: Adenine and Guanine, two rings b) Pyrimidines: Cytosine, Thymine and Uracil, one ring 2. DNA: where the genetic information is stored its shape is a double helix... the spiral shape is made as the nucleotides twist around each other Each step of DNA’s staircase is composed of a base pair: Cytosine and Guanine pair up as well as Thymine and Adenine (connected by hydrogen bonds) Proteins: linear polymers made of amino acids Functions of proteins: 1. Enzyme catalysis: enzymes are proteins that facilitate chemical reactions by stressing certain chemical bonds 2. Defense: some globular proteins use their shapes to recognize cancer and foreign cells and keep them out of the bloodstream (immune system) 3. Transport: membrane transport proteins move ions and molecules across the cell membrane 4. Support: protein fibers provide structure to different parts of the body 5. Regulation: proteins turn on and shut off genes during development and serve as messengers between cells (hormones) 6. Motion: contractile proteins move materials within cells, actin and myosin help muscles contract 7. Storage: Ca and Iron are stored in the body by binding to storage proteins Classes of amino acids: a) Nonpolar amino acids: contains CH or 2 3 b) Polar uncharged amino acids: contains O or OH c) Charged amino acids: contains acids or bases d) Aromatic amino acids: contains a carbon ring with alternating single and double bonds; nonpolar e) Special functioning amino acids: have unique properties More facts about proteins peptide bond: the covalent bond that links amino acids together, forms when the amino end of one amino acid joins to the carboxyl group of another Polypeptide: the long, unbranched chains that compose proteins The SHAPE of a protein determines its FUNCTION Almost all amino acids in a protein are nonpolar because of water’s tendency to avoid nonpolar molecules denaturation: when a protein unfolds and loses its shape because of changes in the protein’s environment motif: common element of secondary structure, can bind DNA, useful in determining the function of unknown proteins domain: functional unit within a larger structure, most proteins made of multiple domains that have different functions perform different parts of the protein’s function Lipids: a group of molecules that are insoluble in water the building blocks of lipids are fatty acids When lipids are put into water, the lipid molecules cluster together and expose their small polar groups to the water, and confine their nonpolar parts within the cluster lipids are good energystorers because they have so many HC bonds terpenes: long chained lipids that comprise pigments like chlorophyll (Ex. Rubber) steroids: lipids composed of 4 carbon rings (Ex. Cholesterol, testosterone, estrogen) prostaglandins: have two polar tails attached to a five Carbon ring; act as local chemical messengers in many vertebrae tissues Structure of a phospholipid: 1) glycerol: forms the backbone; a 3 Carbon alcohol, in which each carbon bears a hydroxyl group 2) fatty acids: attached to the glycerol, long chains of CH2 (hydrocarbon chains) ending in a COOH (carboxyl group) 3) phosphate group: attached to one end of the glycerol, usually has a charged orgainic particle attached to it Chapter 6 Thermodynamics: the branch of chemistry concerned with energy changes energy: the capacity to do work kinetic energy: the energy of motion… moving objects perform work by causing other matter to move potential energy: stored energy… the capacity to move the sun provides energy to all living things: a) energy absorbed from sunlight is used to combine small molecules into more complex ones b) the sun converts carbon from an inorganic to an organic form c) energy from sunlight is stored as potential energy oxidation: when a molecule or atom loses an electron reduction: when a molecule or atom gains an electron (higher level of energy) The Laws of Thermodynamics 1 Law of Thermodynamics: energy cannot be created or destroyed; it can only change from one form to another chemical potential energy that is stored in some molecules can be shifted to other molecules and stored in different chemical bonds… some of the energy dissipates into the environment as heat 2 Law of Thermodynamics: some energy is lost as disorder in the universe entropy: all of the disorder in the universe; constantly increasing Free energy: the energy available to do work in any system; the amount of energy available to break and form other chemical bonds the change in free energy allows us to predict whether a chemical reaction is spontaneous or not change in free energy=energy of productsreactants endergonic reaction: the products have more free energy than the reactants… the reaction is not spontaneous because they need an input of energy exergonic reaction: the products have less free energy than the reactants… the reaction is spontaneous an exergonic reaction has an equilibrium favoring the products, and an endergonic reaction has an equilibrium favoring the reactants activation energy: the extra energy needed to destabilize existing chemical bonds and start a chemical reaction to increase the rate of reactions: a. Increase the energy of reacting molecules b. Lower activation energy catalysts: substances that influence chemical bonds to lower the activation needed to start a reaction ATP: the currency that cells use for energy transactions it powers almost every energy requiring process in cells… makes sugars, supplies energy for chemical reactions, transports substances across membranes structure of ATP: 1. Ribose: 5 carbon sugar that serves as the framework to which the other two subunits are attached 2. Adenine: organic molecule composed of 2 carbonnitrogen rings… weak base 3. Three phosphates How ATP stores energy: the phosphate groups are highly negative charged and repel each other, making the covalent bonds connecting the phosphates unstable when a bond breaks, ATP becomes ADP and a phosphate, and 7.3 kcal/ mole of energy is released cells use ATP to drive endergonic reactions (which don’t proceed spontaneously because their products possess more free energy than their reactants) ATP can provide most of the energy a cell needs: helps generate force in muscles, creates concentration gradients of important ions ATP cycles continuously Enzymes: mostly proteins that act as catalysts to speed up chemical reactions enzymes lower the activation rate of reactions the shape of an enzyme allows it to stabilize an association between substrates (the molecules that will undergo a reaction) by bringing the two substrates together in the correct orientation, which lowers the activation energy required for new bonds to form The enzyme is not changed or consumed in the reaction, so it can be used over and over metabolism: the collection of all chemical reactions By facilitating particular chemical reactions, the enzymes in a cell determine the course of metabolism in that cell active sites: the pockets or clefts on the enzyme that the substrates bind to, forming an enzymesubstrate complex The binding of a substrate makes the enzyme adjust its shape so it fits better with that substrate… this may facilitate the binding of other substrates to the enzyme The steps of catalysis: 1) The substrate (sucrose) consists of glucose and fructose bonded together 2) The substrate binds to the active site of the enzyme, forming an enzymesubstrate complex 3) The binding of the substrate and enzyme places stress on the glucosefructose bond, and the bond breaks 4) Products are released; the enzyme can bond to other substrates Multienzyme complexes: the assemblies of several enzymes catalyzing different steps in a sequence of reactions… speeds the overall process up Advantages of multienzyme complexes: 1) The product of one reaction can be delivered to the next enzyme without releasing it to diffuse away 2) Unwanted side reactions are prevented because the reacting substrate doesn’t leave the complex while it goes through the series of reactions 3) All of the reactions that take place within the multienzyme complex can be controlled as a unit Nonprotein enzymes: enzymes that are not proteins RNA catalysts: “ribosomes,” accelerate the rate of biochemical reactions but aren’t proteins a) Intramolecular catalysis: when the ribosomes have a folded structure and catalyze reactions on themselves b) Intermolecular catalysis: when the ribosomes act on other molecules without being changed themselves Temperature, pH, and the binding of regulatory molecules affect the enzymes ability to catalyze a reaction Temperature: increasing the temp. of an uncatalyzed reaction increases its rate because heat increases molecular movement the rate of an enzymecatalyzed reaction increases with temperature up to the optimum temperature… at extremely high temperatures, the enzyme denatures pH: ionic interactions are sensitive to the H ion concentration of the fluid in which the enzyme is dissolved some enzymes can function in very low pH’s Inhibitors and Activators: enzyme activity is sensitive to the presence of substances that can bind to the enzyme and change its shape inhibitor: a substance that binds to an enzyme and decreases its activity a) competitive inhibitors: compete with the substrate for the same active site, occupying the same site and preventing the substance from binding b) noncompetitive inhibitors: bind to the enzyme in another location, changing the enzymes shape so the substrate can’t bind activator: a substance that binds to an enzyme that increases its activity cofactors: one or more nonprotein components required by enzymes in order to function coenzyme: a nonprotein organic molecule that plays an accessory role in enzyme catalyzed processes by acting as a donor or accepter of electrons Metabolism: the total of all chemical reactions carried out by an organism anabolism: the chemical reactions that expand energy to build up molecules; needs an energy input catabolism: reactions that harvest energy by breaking down molecules; releases energy biochemical pathways: a sequence of chemical reactions in which the product of one reaction becomes the substrate of the next reaction feedback inhibition: control mechanism in which an increase in the concentration of some molecules inhibits the synthesis of the molecule
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