LIFE 102 Week 1
LIFE 102 Week 1 Life 102
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This 24 page Class Notes was uploaded by Kyla Tovar on Saturday August 27, 2016. The Class Notes belongs to Life 102 at 1 MDSS-SGSLM-Langley AFB Advanced Education in General Dentistry 12 Months taught by Jennifer L Neuwald in Fall 2016. Since its upload, it has received 21 views. For similar materials see Attributes of Living Systems in Life Sciences at 1 MDSS-SGSLM-Langley AFB Advanced Education in General Dentistry 12 Months.
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Date Created: 08/27/16
Chapter 1 (Reading): Evolution, The Themes of Biology, and Scientific Inquiry I. Inquiry about Life a. Organisms adaptions to its environment is the result of evolution i. Evolution: the process of change that has transformed life on Earth from its earliest beginnings to the diversity of organisms living today b. Biology: the scientific studying of life i. Posing questions about the living world and seeking answers through scientific inquiry c. Properties of life i. Energy processing ii. Growth and development iii. Responses to the environment iv. Reproduction v. Regulation vi. Evolutionary adaption vii. Order II. The Study of Life Reveals Common Themes a. Levels of Biological Organization i. The Biosphere ii. The Ecosystems 1. All the living things in a particular area, along with all the nonliving components of the environment with which life interacts iii. Communities: the array of organisms inhabiting a particular ecosystem iv. Populations 1. Consists of all the individuals of a species living within the ounds of a specified area v. Organisms: individual living things vi. Organs and Organ System vii. Tissues: a group of cells that work together, performing a specialized function viii. Cells ix. Molecules: chemical structure consisting of two or more units called amino acids x. Organelles III. Theme: New Properties Emerge at Successive Levels of Biological Organization a. The study of life extends from the global scale of the entire living planet to the microscopic scale of cells and molecules b. Reductionism: zooming in at ever-finer resolution illustrates an approach IV. Emergent Properties a. This approach allows us to see novel properties emerge at each level theater absent from the preceding level b. Emergent properties: due to the arrangements and interactions of parts as complexity increase c. Systems biology the exploration of a biological system by analyzing the interactions among its parts i. Used to study life at all levels V. Structure and Function a. Knowing the function of something provides insight into its structure and organization VI. The Cell: An Organism’s Basic Unit of Structure and Function a. The cell is the smallest unit of organization that can perform all activities required for life b. All cells share certain characteristics c. Two types of cells i. Prokaryotic 1. Bacteria 2. Archaea ii. Eukaryotic 1. Plants 2. Animals 3. Contains membrane-enclosed organelles 4. Contains a nucleus d. Prokaryotic cell lacks a nucleus or other membrane-enclosed organelles VII. Theme: Life’s Processes Involve the Expression and Transmission of Genetic Information a. Within cells, chromosomes contain DNA (deoxyribonucleic acid) i. Before cell division the DNA is replicated identical to the parent cell ii. Genes: each a section of the DNA of the chromosome 1. Units of inheritance 2. All the information necessary to build all of the molecules synthesized within a cell a. Establishes the cell’s identity and function 3. A DNA molecule is made up of two long chains, called strains, arranged in a double helix a. Chains made up of nucleotides (A, T, C, G) b. Four letter alphabet 4. Genes provide blueprint to make proteins 5. Genes control protein production indirectly using RNA 6. DNA to RNA to Amino Acids 7. Gene expression: The entire process, by when the information in a gene directs the manufacture of a cellular product 8. RNA molecules are called mRNA iii. Genomics: Large scale Analysis of DNA sequences 1. Genome: the entire library of genetic instructions that an organism inherits 2. Typical human cell has two similar sets of chromosomes, each with 3 billion nucleotide pairs of DNA 3. Genomics: Researchers study whole sets of genes in one or more species 4. Proteomics: Study of sets of proteins and their properties 5. Proteome: The entire set of proteins expressed by a given cell or group of cells 6. High-throughput technology tools that can analyze many biological samples very rapidly 7. Bioinformatics: the use of convential tools to store, organize, and analyze the huge volume of date that results from high-throughput methods 8. The formation of interdisplianry research teams groups of diverse specialists 9. DNA uses transcription to make mRNA uses translation to make chain of amino acids uses protein folding to make protein VIII. Theme: Life Requires the Transfer and Transformation of Energy and Matter a. The chemical energy in the food molecules is then passed along by plants and other photosynthesis organisms (producer) to consumers b. Consumers: organisms that feed on producers and other consumers c. Some energy is lost to heat in work d. Energy flows one way through an ecosystem i. Entering as light, exiting as heat e. Chemicals are recycled in an ecosystem IX. Theme: From Ecosystem to Molecules, Interactions are Important in Biological Systems a. Ecosystems: an organism’s interactions with other organisms and the physical environment i. Some cases, interactions between organisms are mutually beneficial 1. Ex: turtle surrounded by cleaner food that feed on parasites harmful to turtles ii. Some cases, only one organism benefits 1. Ex: A hawk eating a fish iii. Some cases, both are harmed 1. Ex: two plants fighting over soil supply b. Molecules: interactions within organisms i. At lower levels of organization, the interaction between organisms are crucial to their smooth operation ii. Feedback regulation: the output of a process regulates that very process 1. Most common is negative feedback 2. Positive feedback: an end product speeds up its own production a. Clotting of blood after injury b. When chemicals released by the platelets attract more platelets iii.Interactions between individuals not only affect the participants, but also affect how populations evolve over tie c. Evolution, The Core Theme of Biology X. The Core Theme: Evolution accounts for the Unity and Diversity of all Specials on Earth a. Evolutionary mechanisms account for the unity and diversity of all species on Earth b. Classifying the Diversity of Life i. 1. 8 million species ii. Estimate of total number of species range from 10 million to over 100 million c. Grouping Species: The Basic Idea i. The three Domains of Life 1. Comparisons of structure, function, and other obvious features 2. 6 to dozens of kingdoms 3. Grouped into threw higher levels called domains: Bacteria, Archaea, and Eukarya 4. Eukarya a. Multicellular eukaryote: kingdom Plantae, Fungi and Animalia i. Distinguished by their modes of nutrition ii. Plants produce their own sugars and other food molecules by photosynthesis iii. Fungi absorb dissolved nutrients from their surroundings iv. Animals obtain food by eating and digesting other organisms v. Protists split into multiple kingdoms d. Unity in the Diversity of Life i. Similarities between organisms are evident at all levels of the biological hierarchy e. Charles Darwin and the Theory of Natural Selection i. Came in November 189, Charles Darwin published book entitled “On the Origin of Species by Means of Natural Selection” 1. Contemporary species arose from a succession of ancestors that differed from them (descents w/ modification) 2. Natural selection I an evolutionary mechanism for descent w/ modification ii. Started w/ 3 observations 1. Individuals in a population vary in their traits 2. A population can produce far more offspring than can survive to produce offspring of their own 3. Species generally suit their environments iii. Using these 3 observation made the theory of evolution iv. Natural selection: the natural environment selects for the propagation of certain traits among naturally occurring variant traits in the population f. The Tree of Life i. Natural selection could create new species XI. In Studying Nature, Scientists Make Observations and Form and Test Hypotheses a. Inquiry: a search for information and explanation of natural phenomena b. There is no formula for successful scientific inquiry c. Process includes making observations, forming logical, testable explanations (hypotheses), and testing them d. Making observations i. Describe through careful observation and analysis of data ii. Data: recorded observations 1. Qualitive: recorded description 2. Quantitative: numerical iii. Inductive reasoning: collecting and analyzing descriptions can lead to important conclusions based on a type of logic iv. Forming and Testing Hypotheses 1. Hypothesis: tentative answer to a well framed question a. Has to be able to be tested 2. Deductive reasoning: logic that is specific a. We can never prove that a hypothesis is true 3. Questions That can and Cannot Be Addressed by Science 4. The Flexibility of the Scientific Process XII. A Case Study in Scientific Inquiry: Investigating Coat Coloration in Mouse Populations a. Sets of observations and inductive generations b. Colors to protect from predators c. Experimental variables and controls i. Experiment: manipulation of one factor in a system in order to see the effects of changing it ii. Variables: factors that vary in an experiment iii. Controlled experiment: designed to compare an experiment group with a control group iv. Independent variable: factor manipulated v. Dependent variable: measured 1. The independent variable affects the dependent variable vi. In an controlled experiment researchers control the unwanted variables d. Theories in Science i. Theories are much broader than a hypothesis ii. Theories can create new hypothesis to be tested iii. A theory is supported by much greater body of evidence XIII. Science benefits from a cooperative approach and diverse viewpoints a. Research results have no impact until shared with a community of peers b. Building on the work of others i. Model organism: aspects that is easy to grow in the lab and lends itself particularly well to the questions being investigated ii. Benefit by making connections between the different levels of biology c. Science, Technology, and Society i. The goal of science is to understand natural phenomena ii. The value of diverse viewpoints Chapter 1: Lecture Life is basically eating, grow, reproduce o Scientifically, the properties of life are order, evolutionary adaption, regulation, energy processing, growth and development, reproduction, and responses to the environment Themes in Biology o Organization The biosphere, the ecosystem, communities, populations, organisms, organs and organ systems, tissues, cells, organelles, molecules Reductionism: reduces complex systems to similar components Emergent properties: properties of life that arise due to the arrangement and interaction of the parts Correlation between the structure and function o Information DNA (deoxyribonucleic acid): universal genetic language common to all organisms Genomic: the study of whole sets of genes and how they are expressed (emergent property)! o Transfer and Transformation of Energy and Matter Moving, growing, reproducing, cellular processing You first need energy o Interactions Sunlight into leaves making energy to take CO2 to make O2 o Evolution: decent with modification (change in heritable traits across generations) o “Nothing in biology makes sense except in the light of evolution” o Taxonomy: classifies species into groups of increasing breadth o Domains of life Bacteria, Archaea, Eukarya o Kingdoms Animalia, Plantae, Fungi, and Protist o Natural Selection Evidence of decent with modification (unity) Natural selection is the mechanism (diversity) Evolution is a fact Best suited to environment are more likely to survive and reproduce Over time, more individuals will have advantageous traits The mechanism for evolution can be explained by the Theory of Natural selection Hypothesis: A tentative statement about the natural world leading to deductions that can be tested Theory: A well-sustained explanation of the natural world that incorporates facts, laws, predictions, and widely tested hypothesis A descriptive generalization about how the natural world behaves understated circumstances Chapter 2: The Chemical Context of Life (Reading) I. A Chemical Connection to Biology a. Chemicals play a major role in insect communication, the attraction of mates, and defense against predators II. Matters Consists of Chemical Elements in Pure Form and In Combinations Called Compounds a. Matter: anything that takes up space and has mass b. Elements and Compounds i. Matter is made up of elements ii. Element: substance that cannot be broken down to other substances by chemical reactions iii. Compound: substance consisting of two or more different elements combined in a fixed ratio c. The Elements of Life i. Essential elements: organism needs to live a healthy life and reproduce 1. 20-25% of total elements ii. Oxygen, Carbon, Hydrogen, and Nitrogen make up 96% of living matter iii. Calcium, Phosphorus, Potassium, and Sulfur make up most of the remaining 4% iv. Trace elements: required by an organism n only minute quantities III. Case Study: Evolution of Tolerance to Toxic Elements a. Some species have become adapted to environments containing elements that are normally toxic IV. An Element’s Properties depend on the Structure of its Atoms a. Atom: smallest unit of matter that stull retains the properties of an element b. Subatomic particles i. Make up atoms ii. Neutrons: neutral charge iii. Protons: positive charge iv. Elections: negative charge v. Atomic nucleus: center of the atom packed with protons and neutrons vi. Rapid moving electrons form a cloud around the nucleus vii. Dalton: used to measure atoms and subatomic particles 1. In honor of John Dalton who helped discover the atomic theory around 1800 2. Same as the atomic mass unit or amu viii. We ignore electrons when calculating mass because its so small c. Atomic number and Atomic Mass i. All atoms of a particular element have the same number of protons in their nuclei ii. Atomic number: number of protons in their nuclei, appears to the left of the symbol for the element iii. Unless otherwise stated an atom is neutral in its charge iv. The atomic number tells us the amount of protons and electrons v. Mass number: sum of protons plus neutrons in the nucleus of an atom 1. Appears above the atomic number vi. Almost all of an atom’s mass is the nucleus vii. Atomic mass: the mass number is an approximation of the total mass of an atom d. Isotypes i. All atoms of a given element have the same number of protons, but can have different amount of neutrons ii. Isotypes: different atomic forms of the same element iii. Even if they have slightly different masses, they behave identically in chemical reactions iv. Radioactive isotopes one in which the nucleus decays spontaneously, giving off particles and energy e. Radioactive Tracers i. Radioactive isotypes used as diagnostic tools in medicine ii. Poses a hazard to life by damaging cellular molecules f. Radiometric Dating i. Used in fossils ii. A parent isotope decays into its daughter isotope at a fixed rate iii. Half-life: the time it takes for 50% of the parent isotope to decay iv. Radiometric dating: measure the ratio of different isotopes and calculate how many half-lives have passed since an organism has fossilized g. The Energy Levels of Electrons i. Atoms are mostly empty space ii. Only electrons are directly involved in chemical reactions iii. Energy: defined as the capacity to cause change iv. Potential energy: the energy that matter possesses because of its location or structure v. The electrons of an atom have potential energy due to their distance from the nucleus vi. An electron can move from one shell to another, but only by absorbing or losing an amount of energy equal to the difference in potential energy between its position in the old shell and that in the new shell vii. Absorbs energy= moves out viii. Loses energy= moves in 1. Lost energy released as heat h. Electron distribution and Chemical Properties i. The chemical behavior of an atom depends mostly on the number of electrons in its outermost shells 1. Valence electrons: outer electrons 2. Valence shell: the outermost electrons shell 3. An atom with a completed valence shell is unreactive ii. Electron Orbitals 1. We never know the exact location of an electron 2. Orbital: the three dimensional space where an electron is found 90% of the time 3. Each electron shell contains electrons at a particular energy level 4. No more than 2 electrons can occupy a single orbital V. The Formation and Function of Molecules depend on Chemical Bonding between atoms a. Atoms with incomplete valence shells can interact with certain other atoms in such a way that each partner completes its valence shell b. The atoms either share or transfer valence shells c. Chemical bonding: atoms staying close together, held by attractions d. Strongest chemical bonds are covalent bonds and ionic bonds e. Covalent bonds: sharing of a pair of valence electrons by 2 atoms f. Molecule: two or more atoms held together by covalent bonds g. Lewis dot structure: electrons sharing can be depicted by an electron distributon diagram h. Structural formula: the line represents a single bond i. Single bond: a pair of shared electrons j. Double bonds: two pairs of shared electron’s k. Atom’s valence: the number of unpaired electrons required to complete the atom’s outermost shell l. Electronegativity: the attraction of a particular atom for the electrons of a covalent bond m. The more electronegative an atom, the more strongly it pulls shared electrons n. In a covalent bond the electrons are shared equally because it is the same electronegativity is a nonpolar covalent bond o. Polar covalent bond: atom is bonded to a more electronegative atom, not equally shared p. Oxygen is one of the most electronegative elements VI. Ionic Bonds a. Two atoms are so unequal in their attraction for valence electrons that the more electronegative atom strips an electron from its partner b. Ions: the two resulting oppositely charged atoms c. Cation: a positively charged ion d. Anion: a negatively charged ion e. Ionic bond: only two ions of opposite charge form f. Ionic compounds: compounds formed by ionic bonds g. Ionic compound does not consist of molecules h. Not all salts have equal numbers of anions and cations i. The term ion also applies to entire molecules that are electrically charged j. Environment affects the strength of ionic bonds VII. Weak Chemical Bonds a. Strongest chemical bonds are covalent bonds b. Weak bonds when two molecules come together allowing easy separation c. Hydrogen Bonds i. When a hydrogen atom is covalently bonded to an electronegative atom, the hydrogen atom has a partial positive charge that allows it to attract different atom ii. Hydrogen bond: the attraction between a hydrogen and an electronegative atom d. Van der Waals Interaction i. Nonpolar covalent bonds can have positive and negative charged region ii. Van der Waals interaction: individually weak and occur only when atoms and molecules are very close together e. Molecular Shape and Function i. Molecule has a characteristic size and precise shape, crucial to function ii. Two atoms are always linear iii. Shape determines how biological molecules recognize and responds to one another with specificity VIII. Chemical Reactions Make and Break Chemical Bonds a. Chemical reactions: the making and breaking of chemical bonds, leading to changes in the composition of matter b. Reactants: starting materials c. Products: end material d. All atoms of the reactants must be accounted for in the products e. Two opposite-headed arrows indicated the re3action is reversible f. Chemical equilibrium: reactions offset one another Chapter 2 Lecture Emergent properties: studying the arrangement and interactions of parts of an organism Studying chemistry for biology is critical The Basics o Matter: takes up space and has mass (composed of elements) o Element: cannot be broken down by chemical reaction o Compound: 2 or more different elements combined in a fixed ratio and has different properties (emergent properties) change from what the properties would be as an element o 25 chemical elements essential for life o Oxygen, Carbon, Hydrogen, and Nitrogen make up 96.3% of the human body Can be remembered by CHON or HONC o 3.7% is a Calcium, Phosphorus, Potassium, Sulfur, Sodium, Chlorine, and Magnesium o Trace elements: present (and needed) in trace amounts, which make up less than 0.01% of mass o These may flip around in different organisms What determines an element’s properties? o Atom: Smallest unit of an element Contain subatomic particles Electrons are not in a certain orbit Mostly empty space Electrons, neutrons, protons take up a very little amount of space o Atoms and Subatomic Particles Neutron Charge: 0 Weight: 1 Dalton Proton Charge 1+ Weight: 1 Dalton Electron Charge: 1- Weight: 0 Dalton ( not weighed in daltons) 1 da (Dalton) 1.7x10^-24 grams Mass number: Total number of protons and neutrons also atomic maass Atomic number: Total # protons If you change the number f protons, it will be a different element Isotopes: two atoms of the same element can differ in the number of neutrons You can tell it’s an isotope by the mass number changing Radioactive: unstable to spontaneously decay (lose energy and neutrons) is radiation o Periodic Table of Elements Electrons are arranged in shells and can be seen by horizontal rows First shell: 2 electrons Second shell: 8 electrons o Electrons and Their Shells Different distances to the nucleus depending on the shell Electrons move between shells= energy, meaning the more outer shell has more energy Each shell can hold a max number of electrons Outmost shell= valence shell The max number in a shell is 32 electrons If the electron goes in energy is released o Atom Behavior Number of electrons in valence shell=behavior of atom Want to have a full valence shell Generally the number of electrons= in between the number of protons and neutrons Ions= the number of electrons and protons is different resulting in a positive or negative charge Electrons can be donated or received in order to get a full valence shell Anion: negative charge atom (receive an electron) Cation: positive charge atom (donate an electron) Electronegativity: ability to attract electrons On periodic table, right to left means low to high electronegativity The last column has full valence shell which is called inert Will not attract other atoms in this row Chemical bonds: an attraction that holds atoms together in a compound Ionic bonds: weak bonds, after ions are formed, the positive and negative charges keep the cation and anion atoms together The electron donated becomes ions formed becomes ionic bonds formed Covalent bonds: strong, sharing a pair of valence electrons by two atoms 1 bond= 1 electron pair double bond= 2 electron pairs Molecule: 2 or more atoms, connected by covalent bonds How many covalent bonds depends on the valence shells Polar covalent bonds: one of the atoms attracts the shared electron pair more strongly than the other ( so molecule is charged) Non polar: electron is shared equally (no charge) Chapter 3: water and Life (reading) I. The Molecule that Supports All of Life a. Life began in water b. All organisms are made mostly of water c. Water is the only substance to exist in the natural environment inn all three physical states of matter II. Polar Covalent Bonds in Water Molecules Result in Hydrogen Bonding a. Water molecule shaped like a wide V b. 2 Hydrogen joined by single covalent bonds to oxygen c. Polar covalent bonds: electrons of the covalent bonds spend more time closer to more electronegative atom d. Polar molecule: unequal sharing of charge e. Hydrogen bonds are very fragile i. Form, break, and reform with great frequency III. Four Emergent Properties of Water Contribute to Earth’s Sustainability for Life a. Cohesion of water molecules i. Water molecules stay close to each other as a result of hydrogen bonding ii. Cohesion: the hydrogen bonds hold the substance together iii. Cohesion contributes to transport of water and dissolved nutrients against gravity iv. Adhesion: the clinging of one substance to another v. Surface tension: a measure of how difficult it is to stretch or break the surface of a liquid vi. Water has an unusually high surface tension b. Moderation of Temperature by Water i. Water moderates air temperature by absorbing heat from air that is warmer and releasing the shared heat to air that is cooler ii. Temperature and Heat 1. Kinetic energy: the energy of motion a. Anything that moves has kinetic energy 2. Thermal energy: kinetic energy associated with the random movement of atoms or molecules 3. Temperature: a measure of energy that represents the average kinetic energy of the molecules in a body of matter 4. Whenever two objects of different temperature are brought together, thermal energy passes from the warmer to the cooler object until the two are the same temperature 5. Heat: thermal energy in transferred from one body of matter to another 6. Calorie (cal): one convenient unit of heat 7. Kilocalorie(kcal): 1,000 cal is the quantity of heat required to raise the temperature of 1 kilogram of water by 1 C 8. Joule (J): energy unit iii. Water’s High Specific Heat 1. Specific heat: the amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature by 1 C 2. Organisms are main primarily of water, they are able to resist changes in their own temperatures iv. Evaporate Cooling 1. Molecules of a liquid stay close 2. If liquid is heated, the average kinetic energy of molecules increases and liquid evaporated more rapidly 3. Heat of vaporization: the quantity of heat a liquid must absorb for 1 g of it to be converted from the liquid to the gaseous state 4. Evaporate cooling: liquid evaporates, the surface of the liquid that remains behind cools down v. Floating of Ice on Liquid Water 1. Few substances less dense as a solid then a liquid a. Cause is hydrogen bonding vi. Water: The Solvent of Life 1. Solution: a liquid that is completely homogeneous mixture of two or more substances 2. Solvent: the dissolving agent of a solution 3. Solute: substance dissolved 4. Aqueous solution: the solute is dissolved in water a. Solvent because polarity of water molecule 5. Hydration shell: the sphere of water molecules around each dissolved ion 6. H compound does not need to be ionic to dissolve in water vii. Hydrophilic and Hydrophobic Substances 1. Hydrophilic: Any substance that has an affinity for water a. Without actually dissolving 2. Hydrophobic: substances that are ionic and non- polar, seem to repel water a. Share electrons almost equally 3. Solute Concentration in Aqueous Solution a. Molecule mass: sum of the masses of all the atoms in a molecule b. Moles (mole): represent an exact number of objects c. 6.02x10^23 is Avogadro’s Number d. Molarity: the number of moles of solute per liter of solution 4. Possible Evolution of Life on Other Planets a. Planets that might have water are looked at IV. Acidic and Basic Conditions i. Hydrogen ion: a single proton with a charge of 1+ ii. Hydroxide ion: lost a electron, charge of 1- iii. H^+ and OH^- are very reactive iv. Acids and Bases 1. When acids dissolve in water they donate additional H^+ to the solution 2. Acid: substance that increases the hydrogen ion concentration of a solution 3. Base: a substance that reduces the hydrogen ion concentration of a solution 4. Can directly or indirectly reduce H^+ concentration v. The pH scale 1. O Acidic, 14 basic, 7 neutral 2. pH: negative logarithm of the hydrogen in concentration a. pH=-log(H^+) 3. Buffers a. Internal pH of many living cells close to 7 b. Slight change in pH can be harmful c. Buffer: substance that minimizes changes in the concentration of H^+ and OH^- in a solution b. Acidification: A Threat to Water Quality i. Burning of fossil fuels ii. Ocean acidification: CO2 dissolves in saltwater, it reacts with water to form carbonic acid, which lowers oceans’ pH Chapter 3 (Lecture) 2) Covalent Bonds Polar=one of the atoms attracts the shared electron pair more strongly than the other (so molecule is charged) o When one atom is more electronegative than the other Non-Polar=electrons are shared equally (no charge) 3) Hydrogen Bonds (weak) Definition: H atom with a partial positive charge from a covalent bond attracts to different electronegative atom o Opposites attract o Weak bonds do not mean not important Chemical Reactions: molecules react with each other, bonds between atoms in reactants are broken atoms are rearranged, and new bonds are formed o Reactants with a reaction get to products o All chemical reactions are reversible o Mass conservation law: all atoms present in the reactants are still present in the products Chapter 3: Water and Life: Water is the molecule of life Water is a polar covalent bond Electronegativity influences the distribution of electrons in the molecule The polarity of H2O results in hydrogen bonding among H2O molecules o Think of positives attracts negatives o H2O will be in sets of 5 Emergent properties related to hydrogen bonds in water: o 1) because of the hydrogen bonds, water is… cohesive=H2O molecules stick together high surface tension Adhesive=H2O molecules stick to substances Important for vascular plants o 2) Because of the hydrogen bonds, water has.. High Specific Heat=more electrons needed to change temperature Number of calories to change temperature of 1 gram by 1 C st As temperature increase: 1 break H- Bonds… which absorbs heat.. so heats slowly As temperature decrease: 1 form H-bonds…which then releases heat.. so cools slowly Temperature is the level of movement High specific heat=climate stability When you are away from water, sun heats up area quickly, and drops at night more quickly Water helps maintain stability of temperature High heat of Vaporization=more electrons needed to change 1 g of liquid to gas Actual change of liquid to gas is evaporation A lot of heat to vaporize water Allows for evaporative cooling o Molecules that are hottest will vaporize first, results in cooler H2O molecules left behind Because of the hydrogen bonds, water has… Floating ice=liquid water is denser than solid water o Ice: Hydrogen bonds are stable, ordered in 5 bonds o Floating ice allows life to live Because of hydrogen bonds, water acts as a.. Solvent=dissolves polar molecules or ionic compounds o Solution: homogeneous mixture of substances o Ex: H2O and NaCl Solvent: dissolving agent o Ex: H2O Solute: substance being dissolved o Ex: NaCl Creates Hydration Shell o Pulls molecules apart and work inward Water soluble: dissolves in water Aqueous solution: water used as solvent Hydrophobic: avoids water, non-polar molecules Hydrophilic: loves water, polar molecules Ice Density: water has more molecules in a space, when solid ice will expand Factors that Influence Properties of Solutions Concentration: number of solute molecules o 1 mole: 6.02 x 10^23 molecules (Avogadro’s number) o molarity: number moles per liter of solution Molecular weight: (MW) weight, in grams, of 1 mole of a compound Ex: glucose-C6H12O6 MW=(6x12)+(12x1)+(6+16) (number of atoms x mass number) 1 mole glucose + water to a final volume of 1 liter
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