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Essential Chemistry for Biology




A 2 full paper reflection paper with Min 600 words.;Attachments Preview;BSC1020_Chapter02_PPT Lecture.pdf Download Attachment;Chapter 2;BIOLOGY AND SOCIETY;M ore Precious than Gold;A drought is;Essential Chemistry for Biology;a period of abnormally dry weather that changes the;environment and;one of the most devastating disasters.;Figure 2.0;BIOLOGY AND SOCIETY;M ore Precious than Gold;Droughts can cause;severe crop damage, shortages of drinking water;dust storms, famine, habitat loss, and mass migration.;Throughout human history, droughts have helped wipe;out societies and even whole civilizations.;SOME BASIC CHEMISTRY;Why chemistry? I thought this was a biology;course;Well, take any biological system apart, and you;eventually end up at the chemical level.;Indeed, your body is one big container of;chemicals undergoing a continuous series of;chemical reactions;Droughts are catastrophic because life cannot exist;without water.;Matter: Elements and Compounds;Matter is anything that occupies space and has;mass.;Matter is found on the Earth in three physical;states;Solid;Liquid;Gas;Matter is composed of chemical elements.;An element is a substance that cannot be;broken down into other substances by;chemical reactions;There are 92 naturally occurring elements on;Earth.;Each element has its own symbol;All of the elements are listed in the;periodic table.;1;Figure 2.1;Atomic number;(number of protons);6;C;Element symbol;12;H;Mass number;(number of;protons plus neutrons);He;Li Be;B;C;N;Na Mg;Al Si P;O;F Ne;S Cl Ar;Lead (Pb);Copper (Cu);K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr;Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te;I;Xe;Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn;Fr Ra Ac Rf Db Sg Bh Hs Mt Uun Uuu Uub;Uuq;Uuh;Uuo;Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu;Mercury (Hg);Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr;Figure 2.1;Carbon (C): 18.5%;Twenty-five elements are essential to people;Oxygen (O);65.0%;Other organisms need fewer;Four elements make up about 96% of the weight;of most cells;Oxygen (O);Hydrogen (H);9.5%;Carbon (C);Hydrogen (H);Nitrogen (N);3.3%;Nitrogen (N);Trace elements;Occur in very small amounts;Calcium (Ca): 1.5%;Phosphorus (P): 1.0%;Potassium (K): 0.4%;Sulfur (S): 0.3%;Sodium (Na): 0.2%;Chlorine (Cl): 0.2%;Magnesium (Mg): 0.1%;Trace elements: less than 0.01%;Boron (B);Manganese (Mn);Chromium (Cr) Molybdenum (Mo);Cobalt (Co);Selenium (Se);Copper (Cu) Silicon (Si);Fluorine (F);Tin (Sn);Iodine (I);Vanadium (V);Zinc (Zn);Iron (Fe);Figure 2.2;Iodine is an essential ingredient of a hormone produced;by the thyroid gland (in the neck);Iodine deficiency causes goiter.;However, they are essential for life;There are 14 of these elements;Examples;Figure 2.3;Iodine (I);Fluorine (F);Iron (Fe);Fluorine is added to dental products and drinking water;It helps to maintain healthy bones and teeth.;2;Atoms;Elements can combine to form compounds.;Compounds are substances that contain two;or more elements in a fixed ratio.;Common compounds include;NaCl (table salt);Each element consists of one kind of atom.;An atom is the smallest unit of matter that;still retains the properties of an element.;The term comes from a Greek word;meaning indivisible;H2O (water);The Structure of Atoms;2;Protons;2;Neutrons;2;Atoms are composed of subatomic particles.;Electrons;Nucleus;A proton is positively charged.;An electron is negatively charged.;Nucleus;A neutron is electrically neutral.;2e;Electron cloud;Most atoms have protons and neutrons packed tightly;into the nucleus.;The nucleus is the atoms central core.;Electrons orbit the nucleus (in a spherical cloud at;nearly the speed of light!);Figure 2.4;Isotopes;Elements differ in the number of subatomic;particles in their atoms.;The number of protons, the atomic number;determines which element it is.;Isotopes are alternate mass forms of an element.;They have the same number of protons and;electrons, but a different number of neutrons.;Mass is a measure of the amount of matter in;an object.;An atoms mass number is the sum of the;number of protons and neutrons.;3;The nucleus of a radioactive isotope decays;spontaneously, giving off particles and energy.;Radioactive isotopes have many uses in research;and medicine.;They can be used to determine the fate of atoms in;living organisms.;Uncontrolled exposure to radioactive isotopes;can harm living organisms by damaging DNA.;The 1986 Chernobyl nuclear accident;released large amounts of radioactive;isotopes.;Naturally occurring radon gas may cause;lung cancer.;They are used in;PET scans to;diagnose heart;disorders and;some cancers.;Figure 2.5;Electron Arrangement and the Chemical;Properties of Atoms;Protons;Electrons;Positive charge;Determine element;Negative charge;Participate in chemical;reactions;electrons;determine chemical;behavior;Outer-shell;Neutrons;No charge;Determine isotope;Atom;Nucleus;Consists of neutrons;and protons;Of the three subatomic particles, only electrons are;directly involved in the chemical activity of an atom.;Electrons orbit the nucleus of an atom in specific;electron shells.;The farther an electron is from the nucleus, the;greater its energy.;The number of electrons in the outermost shell;determines the chemical properties of an atom.;Figure UN2-5;Chemical Bonding and Molecules;First electron shell;(can hold 2 electrons);Chemical reactions enable atoms to give up or;acquire electrons to complete their outer shells.;Outer electron shell;(can hold 8 electrons);Electron;Chemical reactions usually result in atoms;Staying close together;Hydrogen (H);Carbon (C);Nitrogen (N);Oxygen (O);Atomic number = 1 Atomic number = 6 Atomic number = 7 Atomic number = 8;Being held together by attractions called;chemical bonds;Figure 2.6;4;Ionic Bonds;When an atom loses or gains electrons, it;becomes electrically charged.;Outer shell;has 1 electron;The outer electron is stripped;from sodium and completes;the chlorine atoms outer shell;Complete;outer shells;Outer shell;has 7 electrons;Charged atoms are called ions.;Ionic bonds are formed between oppositely;charged ions.;Na;Sodium atom;Cl;Chlorine atom;Animation: Ionic Bonds;Na+;Sodium ion;The attraction;between the;ionsan ionic;bondholds;them together;Cl;Chlorine ion;Sodium chloride (NaCl);Note: All animations referred to in this handout;are found in the Chapter 2 Folder on Blackboard;Attraction between oppositely;charged ions holds the ions in;an ionic bond.;Figure 2.7;Covalent Bonds;A covalent bond forms when two atoms share one or;more pairs of outer-shell electrons.;They are the strongest of the bonds discussed here;Atoms held together by covalent bonds form a;molecule.;The number of covalent bonds an atom can form is;equal to the number of additional electrons needed to fill;its outer shell.;Lithium ion;Fluoride ion;Blast Animation: Covalent Bonds;Lithium fluoride (ionic compound);Electron configuration;H;Animation: Covalent Bonds;Figure UN2-6;Structural formula Space-filling model Ball-and-stick model;Electron sharing;H;Hydrogen gas (H2);O;Single bond;(a pair of shared electrons);O;Oxygen gas (O2);Double bond;(two pairs of;shared electrons);H;H;C;H;H;Methane (CH4);Figure 2.8;Atoms joined into a molecule;via covalent bonds;Figure UN2-7;5;Hydrogen Bonds;+);(slightly +);Water is a compound in which the electrons in its;covalent bonds are shared unequally.;+);(slightly +);H;H;This causes water to be a polar molecule;one with an uneven distribution of charge;O has a ve charge and the Hs a +ve charge;O;Blast Animation: Hydrogen Bonds in Water;Animation: Water Structure;(slightly);Figure UN2-2;Chemical Reactions;The polarity of water results in weak electrical;attractions between neighboring water molecules.;These interactions are;called hydrogen bonds.;Cells constantly rearrange molecules by breaking;existing chemical bonds and forming new ones.;Such changes in the chemical composition of;matter are called chemical reactions.;Hydrogen bond;Slightly;positive;charge;Chemical reactions include;Slightly;negative;charge;Reactants, the starting materials;Products, the end materials;Figure 2.9;2 H2;Hydrogen;gas;+;O2;Oxygen;gas;Reactants;2 H2O;Water;Chemical reactions cannot create or destroy;matter, but only rearrange it;These rearrangements usually involve the;breaking of chemical bonds in the reactants;and the forming of new bonds in the products;Products;Figure UN2-3;6;WATER AND LIFE;Life on Earth began in water and evolved there;for 3 billion years.;Modern life remains tied to water.;Your cells are composed of 70%95% water.;The abundance of water is a major reason Earth;is habitable.;Waters unique life-supporting properties are tied;to the structure and interaction of its molecules;Figure 2.10;Waters Life-Supporting Properties;The Cohesion of Water;The polarity of water molecules and the;hydrogen bonding that results explain most of;waters life-supporting properties.;Water molecules stick together as a result of;hydrogen bonding.;Water molecules stick together.;This tendency of molecules of the same kind;to stick together is called cohesion.;Water has a strong resistance to change in;temperature.;Cohesion is vital for the transport of water;from the roots to the leaves of plants.;Frozen water floats.;Animation: Water Transport;Water is a common solvent for life.;Figure 2.11;Surface tension is the measure of how difficult it;is to stretch or break the surface of a liquid.;Evaporation from the leaves;Hydrogen bonds give water an unusually high;surface tension.;M icroscopic water-conducting tubes;SEM;Cohesion due to;hydrogen bonds;between water;molecules;Figure 2.12;7;How Water Moderates Temperature;Because of hydrogen bonding, water has a strong;resistance to temperature change.;Heat and temperature are related, but different.;Heat is the amount of energy associated with;the movement of the atoms and molecules in;a body of matter.;Temperature measures the intensity of heat.;Water can moderate temperatures.;Earths giant water supply causes temperatures;to stay within limits that permit life.;Evaporative cooling occurs when a substance;evaporates and the;surface of the liquid;remaining behind;cools down.;Sweating;Water can absorb and store large amounts of heat;while only changing a few degrees in temperature;Figure 2.13;The Biological Significance of Ice Floating;Hydrogen bond;When water molecules get cold enough, they;move apart, forming ice.;A chunk of ice has fewer molecules than an equal;volume of liquid water.;Ice floats because it is less dense than the liquid;water around it.;Like waters other life-supporting properties;floating ice is a consequence of hydrogen-bonding;Liquid water;Hydrogen bonds;constantly break;and re-form.;Ice;Stable hydrogen bonds;hold molecules apart;making ice less dense;than water.;Figure 2.14;Water as the Solvent of Life;If ice did not float, ponds, lakes, and even the;oceans would freeze solid.;Life in water could not survive if bodies of water;froze solid.;Thus, the floating ice forms an insulating;blanket, allowing life to persist under the;frozen surface;A solution is a liquid consisting of a;homogeneous mixture of two or more;substances.;The dissolving agent is the solvent.;The dissolved substance is the solute.;When water is the solvent, the result is an;aqueous solution.;8;The Process of Science;Can Exercise Boost Your Brain Power?;Sodium ion;in solution;Chloride ion;in solution;Cl;Observation: Human brains shrink as we age.;Na+;Cl;Question: Can aerobic exercise slow or reverse;brain loss?;Hypothesis: MRI scans would reveal differences;between people who regularly exercised;aerobically and those who did not.;Na+;Salt crystal;Figure 2.15;Prediction: Brains of active people would shrink;less than the brains of less active people.;Experiment: Twenty-nine people in their 60s;and 70s exercised for three one-hour sessions per;week. A control group of 29 people engaged in;non-aerobic stretching exercises for the same;periods.;Results: The aerobic group showed significant;increases in brain volume compared to the nonaerobic group.;Figure 2.16;14;Acids, Bases, and pH;To describe the acidity of a solution, chemists;use the pH scale.;13;Household;bleach;12;Household ammonia;+;Lower H+ concentration;A compound that accepts H+ and removes it from;solution is a base.;Basic;solution;11;Milk of magnesia;10;9;Seawater;8;+;H+;OH;+;OH;H+;OH;+;H+ +;+;OH H;Neutral;solution;+;+;H+ H+;+;+;+;OH H H+;+;H+ +OH;H+;[H+ ] = [OH];Human blood;7 Pure water;6 Urine;+;Greater H+ concentration;A chemical compound that releases H+ to;solution is an acid.;Oven cleaner;OH;OHOH;OH H+OH;+;+;OH H+;5;4;3 Grapefruit juice;soft drink;2;1;Acidic;solution;Black coffee;Tomato juice;Lemon juice;stomach acid;Battery acid;0;pH scale;Figure 2.17;9;Basic;Neutral;[H+ ] = [OH];Neutral;solution;Basic;solution;Acidic;solution;Acidic;pH scale;pH 14;Lower H+;concentration;pH 7 H+ concentration equal;to OH concentration;Greater H+;concentration;pH 0;Figure UN2-10;Evolution Connection;The Search for Extraterrestrial Life;Buffers are substances that resist pH change.;They accept H+ ions when they are in excess;They donate H+ ions when they are depleted;Increases in global CO2 concentrations may lead to the;acidification of the oceans;Undersea volcanoes;also release high levels;of CO2;If life similar to ours has evolved elsewhere in the;universe, then it too would depend upon water.;Recent NASA missions to Mars have detected;evidence that liquid water flowed over the planets;surface.;This raises the tantalizing possibility that;microbial life may exist below the Martian;surface;Figure 2.18;Ice;Figure 2.19;10;View Full Attachment;BSC1020_Chapter03_PPT Lecture (1).pdf Download Attachment;BIOLOGY AND SOCIETY;Got Lactose?... Show more;BSC1020_Textbook_Chapter2.pdf Download Attachment;000200010271726115_CH02.pdf 10/29/2012 1:49:53 PM;Unit 1... Show more;BSC1020_Textbook_Chapter3.pdf Download Attachment;000200010271726115_CH03.pdf 10/29/2012 1:50:04 PM... Show more;Requirement.docx Download Attachment;Reflection paper;Two full pages (double-spaced, 1 inch margins, size 12 font). In some chapters, the;PowerPoint lectures may include material that is not in the text. In such cases, your;summaries should reflect also what was covered in these handouts. Units should be;summarized in paragraph-form, not numbered or bulleted.;These papers should also be in your own words. Please DONT plagiarize the textbook;or other sources.


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