Physico chemical basis of life


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  • Calcium: The mineral that strengthens bone and teeth uses calcium. Also important in nerve synaptic transmission of nerve impulses and muscle contraction. Regulates the cell wall construction in plants. Phosphorus: Part of the phosphate groups in ATP and DNA molecules. In plants it is needed for cell reproduction and division. It is part of the cell membrane. Iron: found in the structure of hemoglobin and essential for the production of red blood cells. It is involved in the light energy transferring compounds involved in photosynthesis in plants. Sodium: Major ion associated with the propagation of a nerve impulse. Can replace potassium in some plants. Sulfur: It is a component of amino acids.
  • Physico chemical basis of life

    1. 1. Physico-Chemical Basis of Life Joy Grace Tablante More Free PowerPoint Templates at
    2. 2. Physical Basis <ul><li>Matter makes up both living and nonliving things. </li></ul><ul><li>Biologists study the nonliving particles </li></ul><ul><li>(chemical aspect) of which matter is made of in order to understand better the biological function of living things. </li></ul><ul><li>Living things also depend on a constant supply of energy. </li></ul><ul><li>Together matter and energy are the physical basis of Life. </li></ul>
    3. 3. Matter Flowchart MATTER Can it be physically separated? Homogeneous Mixture (solution) Heterogeneous Mixture Compound yes no Element MIXTURE PURE SUBSTANCE Can it be chemically decomposed? no yes Is the composition uniform? no yes Colloids Suspensions
    4. 4. Chemical Basis <ul><ul><li>Chemicals play many more roles in life </li></ul></ul><ul><ul><ul><li>Making up our bodies, those of other organisms, and the physical environment </li></ul></ul></ul><ul><ul><ul><li>The food we eat </li></ul></ul></ul><ul><ul><ul><li>The water we drink </li></ul></ul></ul><ul><ul><ul><ul><li>Water makes up 65 to 90% of the weight of the human body </li></ul></ul></ul></ul><ul><li>Biological functions starts at the chemical level </li></ul><ul><li>example: </li></ul><ul><li>Life is composed of matter </li></ul><ul><li>Matter is composed of chemical elements </li></ul><ul><li>Each element consists of one type of atom </li></ul><ul><li>Certain atoms combine to form the complex molecule chlorophyll </li></ul><ul><li>Many chlorophyll molecules are located in organelles called chloroplasts </li></ul><ul><li>Many chloroplasts are located in cells of photosynthetic tissues in structures ( organs ) such as leaves of plants </li></ul>
    5. 5. <ul><li>Matter—anything having mass and occupying space </li></ul><ul><li>Mass—a measure of the amount of matter that an object contains </li></ul><ul><li>Mass vs Weight </li></ul><ul><ul><li>Weight is the measure of how strongly an object is pulled by earth’s gravity and consequently varies as a function of distance from the earth’s center. Mass does not vary with its position </li></ul></ul><ul><li>Substances can either be classified as elements or compounds </li></ul><ul><ul><li>Elements: pure, cannot be broken down </li></ul></ul><ul><ul><li>Compounds: Can be broken down into two or more substances </li></ul></ul><ul><ul><li>NOTE: for further information about compounds please view </li></ul></ul><ul><ul><li>Bio-Substances ppt at </li></ul></ul>MATTER
    6. 6. Compounds can either be Inorganic or Organic. These compounds are nutrients which provide energy or materials for all cell activities. Living things are mostly made of organic compounds that contain carbon and hydrogen. Often they contain oxygen too
    7. 7. <ul><li>These organic compounds can also have amounts of nitrogen, calcium and phosphorous. They may have varying small amounts of other elements called “trace elements” like potassium, iodine, sulfur, iron, magnesium and sodium. </li></ul><ul><li>Living things also need inorganic compounds like water and salts. </li></ul>
    8. 8. <ul><li>Are particular kind of matter that cannot be separated into other kinds and are listed in the chart known as the periodic table </li></ul><ul><li>Scientists have found that 92 different kinds of elements exists in nature. They have also created additional ones in the lab. </li></ul><ul><li>Just as primary colors combine in different ways to make up every color we can see, the different elements combine in different ways to make up all substances. </li></ul><ul><li>Metals such as gold, silver and iron –in their pure forms are all elements. </li></ul>ELEMENTS
    9. 10. <ul><li>Living organisms are composed of about 25 chemical elements </li></ul><ul><li>There are 11 major elements in the human body. </li></ul><ul><ul><li>4 of these elements make up 96% of the bulk material in the human body </li></ul></ul><ul><ul><li>The remaining elements constitute 4% of the material of the human body. </li></ul></ul>
    10. 11. <ul><ul><li>Trace elements </li></ul></ul><ul><ul><ul><li>Are essential to life, but occur in minute amounts </li></ul></ul></ul><ul><ul><ul><li>Dietary deficiencies in trace elements </li></ul></ul></ul><ul><ul><ul><li>Can cause various physiological conditions </li></ul></ul></ul><ul><li>Calcium: Deficiencies can contribute to osteoporosis. </li></ul><ul><li>Copper: Deficiencies of copper can cause premature hair graying, sterility and premature wrinkling of the skin. </li></ul><ul><li>Iodine: Deficiencies of iodine can cause a thyroid imbalance or reduced fertility. </li></ul><ul><li>Selenium: Deficiencies of selenium can cause people to age prematurely or to have slower than normal recovery from illnesses. </li></ul><ul><li>Zinc: Deficiencies of zinc can cause sterility, impotence and even depression. </li></ul><ul><li>Iron: is a component of molecules that transport oxygen in blood. </li></ul>TRACE ELEMENTS
    11. 12. <ul><li>A diamond is made of element carbon. </li></ul><ul><li>All elements are made of tiny particles called atoms. </li></ul><ul><li>Balloons that rise are filled with the element helium. </li></ul><ul><li>The mercury in a thermometer is a liquid element. </li></ul>
    12. 13. ATOM <ul><li>Each of the 116 elements consist of only one type of atom. </li></ul><ul><li>from the Greek word “ atomos” for indivisible (cannot be divided) </li></ul><ul><li>If you keep slicing an element in half, eventually you slice to its smallest particle, an atom </li></ul><ul><li>3,000,000 C atoms stretch across the diameter of a period! </li></ul>
    13. 14. ATOMS <ul><li>Pinheads have a diameter of about 0.001meters (a millimeter ). </li></ul><ul><li>An atom has a diameter of 0.00000000025 meters. </li></ul><ul><li>(1 atom/2.5 x 10-10 meters) * (1 x 10-3 meters) = 4 x 106 atoms </li></ul><ul><li>Four million of them could line up across the head of a pin. </li></ul><ul><li>The nucleus is about 0.01% the diameter of the atom as a whole . If the nucleus had a diameter equal to that of a pinhead, then the atom itself would have a diameter of some 10 meters ( about 39 and a half feet ). </li></ul><ul><li>In other words, atoms are mostly empty space! </li></ul>
    14. 15. <ul><li>Protons (p + ) </li></ul><ul><li>LARGE </li></ul><ul><li>Packed in nucleus </li></ul><ul><li>The number of protons determines the elements chemical identity </li></ul><ul><li>Have a + positive charge </li></ul><ul><li>The # of protons is called the ATOMIC NUMBER </li></ul><ul><li>Neutrons (n 0 ) </li></ul><ul><li>Same size as protons </li></ul><ul><li>1 atomic mass unit (amu) </li></ul><ul><li>Also packed in nucleus </li></ul><ul><li>No charge, neutral </li></ul><ul><li>The number of protons plus the number of neutrons is called the MASS NUMBER </li></ul><ul><li>Electrons (e - ) </li></ul><ul><li>Very small </li></ul><ul><li>0.0005486 amu </li></ul><ul><li>Have a -negative charge (equal and opposite to the positive charge of a proton) </li></ul><ul><li>Whirl around the nucleus in area call energy levels or orbitals </li></ul><ul><li>Their exact path is completely unpredictable </li></ul><ul><li>1 st energy level holds 2 e - , 2 nd energy level holds 8 e - </li></ul><ul><li>Like a fly buzzing around Force Field </li></ul>
    15. 16. Atomic Number
    16. 17. Mass Number <ul><li>Is adding the number of protons to the number of neutrons </li></ul><ul><li>Subtracting the atomic number from the mass number gives you….. the number of neutrons </li></ul>
    17. 18. ATOMS <ul><li>By definition, atoms are neutral , they have no charge. </li></ul><ul><li>In other words, the number of protons equals the number of electrons. </li></ul>Example:   A Lithium has 3 protons and 3 neutrons inside the nucleus with 3 electrons orbiting around the nucleus as shown below.
    18. 19. IONS “ charged” atoms <ul><li>Atoms that are not neutral </li></ul><ul><li>They have unequal numbers of electrons and protons </li></ul><ul><li>Some might have more protons than electrons (Ca +2 , H + ) cation </li></ul><ul><li>Others might have more electrons than protons (Cl - , O -2 ) anion </li></ul>
    19. 20. CATION ANION when Li, Be and Ca loose their electrons the &quot;new&quot; valence electrons in the ion are drawn in. These elemental ions are stable in the sense that they will not readily gain or loose electrons. However, since they are charged they can combine electrostatically to form ionic bonds. the resulting compound is called &quot;ionic&quot; or &quot;salt&quot;, e.g., Ca+ + 2Cl- ---> Ca(Cl)2 = calcium chloride.                                                                   H + : a positively charged hydrogen ion H : the hydrogen atom H - : a negatively charged hydrogen ion
    20. 21. IONS
    21. 22. <ul><li>Same element with same number of protons, but a different number of neutrons. </li></ul><ul><li>Alternative form of the same element </li></ul><ul><li>The mass number is different, but the atomic number is the same </li></ul><ul><li>Some isotopes are radioactive </li></ul>ISOTOPES
    22. 23. Hydrogen Isotopes
    23. 24. Carbon Isotopes
    24. 25. Radioactive Isotopes (radioisotopes) <ul><li>Some isotopes are radioactive </li></ul><ul><li>Radioactive elements have nuclei that are unstable, they “decay” </li></ul><ul><li>The nucleus falls apart </li></ul><ul><li>The nucleus emits high-energy particles that are like tiny bullets. </li></ul>
    25. 26. Radioactivity <ul><li>Usually caused when the number of neutrons is much greater than the number of protons </li></ul><ul><li>The emitted particles/energy can damage cells via mutation ( if powerful enough ) </li></ul>
    26. 27. Radioactive Isotopes <ul><li>Some are weakly radioactive </li></ul><ul><li>Some can be used as “tracers” </li></ul><ul><ul><li>To follow molecules as they undergo chemical changes in an organism </li></ul></ul><ul><li>Some can be used to target and kill specific cells (radioactive iodine treats hyperthyroidism) </li></ul>
    27. 28. <ul><li>Medical Diagnosis </li></ul><ul><li>Radioactive tracers are often used for diagnosis </li></ul><ul><ul><li>- In combination with sophisticated imaging instruments </li></ul></ul>0
    28. 29. How brain function is studied now? PET, CAT, MRI, etc. Music Appreciation Hearing, speaking, seeing, thinking about words
    29. 30. <ul><li>How an atom hooks up with other atoms to form molecules/compounds </li></ul><ul><li>An atom’s reactivity depends on how many electrons are in its highest Energy level </li></ul><ul><li>A happy, stable atom has a full outermost Energy level </li></ul><ul><li>8 is best </li></ul>REACTIVITY
    30. 31. Reactivity <ul><li>Depends on electrons </li></ul><ul><li>Atoms will either gain, lose, or share electrons to have a full outer level of electrons </li></ul><ul><li>Reactive elements have partly-filled outer energy levels </li></ul><ul><li>Inert (nonreactive) elements have a filled outer energy levels </li></ul><ul><li>Family 18, the noble gases </li></ul>
    31. 32. <ul><li>Atoms whose shells are not full, tend to interact with other atoms and gain, lose , or share electrons. These interactions form chemical bonds </li></ul><ul><li>Types of chemical bonds: </li></ul><ul><li>Ionic bond </li></ul><ul><li>Covalent bond </li></ul><ul><li>Hydrogen bond </li></ul>CHEMICAL BONDS
    32. 33. <ul><ul><li>Are attraction between ions of opposite charge </li></ul></ul><ul><ul><li>When atoms gain or lose electrons </li></ul></ul><ul><ul><ul><li>Charged atoms called ions are created </li></ul></ul></ul>0 IONIC BOND Transfer of electron Na Sodium atom Cl Chlorine atom Na + Sodium ion Cl – Chloride ion Sodium chloride (NaCl) Na Cl Cl Na + – – –
    33. 34. <ul><ul><li>Sodium and chloride ions </li></ul></ul><ul><ul><ul><li>Bond to form sodium chloride, common table salt </li></ul></ul></ul>0 <ul><ul><li>An electrical attraction between ions with opposite charges </li></ul></ul><ul><ul><ul><li>Results in IONIC BOND </li></ul></ul></ul>Na + Cl –
    34. 35. 0 <ul><li>join atoms into molecules through electron sharing </li></ul><ul><ul><li>In covalent bonds, two atoms share one or more pairs of outer shell electrons, forming molecules </li></ul></ul>COVALENT BOND
    35. 36. <ul><li>Sharing of electrons may be EQUAL or UNEQUAL </li></ul><ul><ul><li>A molecule is nonpolar </li></ul></ul><ul><ul><ul><li>When its covalently bonded atoms share electrons equally </li></ul></ul></ul><ul><ul><li>A molecule is polar </li></ul></ul><ul><ul><ul><li>Electrons are shared unequally between atoms, creating a polar covalent bond </li></ul></ul></ul>0
    36. 37. 0 <ul><li>are weak bonds important in the chemistry of life </li></ul><ul><ul><li>The charged regions on water molecules are attracted to the oppositely charged regions on nearby molecules </li></ul></ul>Hydrogen bonding occurs in other biologically important compounds such as proteins and DNA. HYDROGEN BOND Hydrogen bond (+) (+) H H (+) (+) (–) (–) (–) (–) O
    37. 38. <ul><li>Water is the solvent of life </li></ul><ul><li>Polar or charged solutes dissolve when water molecules surround them, forming aqueous solutions </li></ul>0 + – – – – – – – – – – + + + + + Na + + Na + Cl – Ion in solution Salt crystal Cl –
    38. 40. <ul><li>Hydrogen bonds make liquid water cohesive </li></ul><ul><ul><li>Due to hydrogen bonding </li></ul></ul><ul><ul><ul><li>Water molecules can move from a plant’s roots to its leaves by adhesion </li></ul></ul></ul>0
    39. 41. <ul><ul><li>Insects can walk on water due to surface tension </li></ul></ul><ul><ul><ul><li>Created by cohesive water molecules </li></ul></ul></ul>
    40. 42. <ul><li>Matter consists of atoms and molecules in motion. </li></ul>Kinetic Nature of Matter
    41. 43. <ul><li>Solid — have rigid shape, fixed volume. External shape can reflect the atomic and molecular arrangement. </li></ul><ul><ul><li>Reasonably well understood. </li></ul></ul><ul><li>Liquid — have no fixed shape and may not fill a container completely. </li></ul><ul><ul><li>Not well understood. </li></ul></ul><ul><li>Gas — expand to fill their container. </li></ul><ul><ul><li>Good theoretical understanding. </li></ul></ul>Phases of Matter
    42. 44. <ul><li>PLASMA — an electrically charged gas; Example: the sun or any other star </li></ul><ul><li>BOSE-EINSTEIN CONDENSATE — a condensate that forms near absolute zero that has superconductive properties; Example: supercooled Rb gas </li></ul>Other states of matter
    43. 45. Physical Properties <ul><li>What are some physical properties? </li></ul><ul><li>color </li></ul><ul><li>melting and boiling point </li></ul><ul><li>odor </li></ul>
    44. 46. Physical Changes <ul><ul><li>can be observed without changing the identity of the substance </li></ul></ul><ul><li>Some physical changes would be </li></ul><ul><li>boiling of a liquid </li></ul><ul><li>melting of a solid </li></ul><ul><li>dissolving a solid in a liquid to give a homogeneous mixture — a SOLUTION. </li></ul>
    45. 47. <ul><li>Water’s hydrogen bonds regulate temperature </li></ul><ul><ul><li>Water’s ability to store heat ( high heat capacity ) </li></ul></ul><ul><ul><ul><li>Moderates body temperature and climate </li></ul></ul></ul>0 <ul><li>It takes a lot of energy to disrupt hydrogen bonds </li></ul><ul><ul><li>- So water is able to absorb a great deal of heat energy without a large increase in temperature </li></ul></ul><ul><li>As water cools </li></ul><ul><ul><li>- A slight drop in temperature releases a large amount of heat </li></ul></ul>
    46. 48. <ul><li>Water has high heat of vaporization </li></ul><ul><li>A water molecule takes energy with it when it evaporates </li></ul><ul><ul><li>Leading to evaporative cooling </li></ul></ul>0
    47. 49. <ul><li>Ice is less dense than liquid water </li></ul><ul><li>Hydrogen bonds hold molecules in ice farther apart than in liquid water </li></ul><ul><li>Ice is therefore less dense than liquid water which causes it to float </li></ul><ul><li>Floating ice protects lakes and oceans from freezing solid </li></ul>0 Liquid water Hydrogen bonds constantly break and re-form Ice Hydrogen bonds are stable Hydrogen bond
    48. 50. Chemical Properties and Chemical Change <ul><li>Chemical change or chemical reaction — transformation of one or more atoms or molecules into one or more different molecules. </li></ul><ul><li>Burning hydrogen (H2) in oxygen (O2) gives H2O. </li></ul>
    49. 51. Sure Signs of a Chemical Change <ul><li>Heat </li></ul><ul><li>Light </li></ul><ul><li>Gas Produced (not from boiling!) </li></ul><ul><li>Precipitate – a solid formed by mixing two liquids together </li></ul>
    50. 52. Physical vs. Chemical <ul><li>Examples: </li></ul><ul><ul><li>melting point </li></ul></ul><ul><ul><li>flammable </li></ul></ul><ul><ul><li>density </li></ul></ul><ul><ul><li>magnetic </li></ul></ul><ul><ul><li>tarnishes in air </li></ul></ul><ul><ul><li>physical </li></ul></ul><ul><ul><li>chemical </li></ul></ul><ul><ul><li>physical </li></ul></ul><ul><ul><li>physical </li></ul></ul><ul><ul><li>chemical </li></ul></ul>
    51. 53. Physical vs. Chemical <ul><li>Examples: </li></ul><ul><ul><li>rusting iron </li></ul></ul><ul><ul><li>dissolving in water </li></ul></ul><ul><ul><li>burning a log </li></ul></ul><ul><ul><li>melting ice </li></ul></ul><ul><ul><li>grinding spices </li></ul></ul>
    52. 54. Types of Mixtures <ul><li>Variable combination of 2 or more pure substances. </li></ul>Heterogeneous – visibly separate phases Homogeneous – Same throughout
    53. 55. CHEMICAL REACTIONS <ul><li>Chemical reactions change the composition of matter </li></ul><ul><ul><li>In a chemical reaction </li></ul></ul><ul><ul><li>- Reactants interact, atoms rearrange, and products result </li></ul></ul>0 2 H2 O2 2 H2O
    54. 56. Chemical Reactions <ul><li>Synthesis: Results in the formation of new bonds and energy is required for the reaction and the product to form. </li></ul><ul><ul><li>A+B AB </li></ul></ul>
    55. 57. Decomposition <ul><li>A Reactions occur when a complex nutrient is broken down in a cell to release energy for other cellular functions. </li></ul><ul><li>AB A+B </li></ul>
    56. 58. Exchange <ul><li>Reactions can breakdown or decompose in exchange for two new compounds </li></ul><ul><ul><li>AB+CD AD+CB </li></ul></ul>
    57. 59. <ul><li>This is the general equation for photosynthesis—the process of capturing sunlight energy and converting it to chemical energy. Which of the following are the reactants of this reaction? </li></ul><ul><ul><li>C 6 H 12 O 6 and O 2 . </li></ul></ul><ul><ul><li>CO 2 and H 2 O. </li></ul></ul>0
    58. 60. Acids, Bases and Salts
    59. 61. <ul><li>Life processes occur in neutral pH. </li></ul><ul><li>Acids, bases and salts when dissolved in water serve as electrolytes. </li></ul><ul><li>Salts are abundant in our body in the form of different body fluids like sweat and tears. </li></ul>Importance of acids, bases and salts in living organisms
    60. 62. <ul><li>Living organisms are sensitive to acidic and basic conditions </li></ul><ul><li>Acid = An ionic compound that releases H + ions in solution </li></ul><ul><li>Base = An ionic compound that accepts H + ions or produces OH- ions in solution </li></ul><ul><ul><li>Acidity is measured on the pH scale from 0 (most acidic) to 14 (most basic or alkaline) </li></ul></ul>
    61. 64. <ul><li>The pH scale </li></ul>0 <ul><li>The pH of most cells </li></ul><ul><ul><li>Is kept close to 7 (neutral) by buffers </li></ul></ul><ul><li>Buffers are substances that resist pH change </li></ul>Basic solution Oven cleaner Acidic solution Neutral solution pH scale 0 1 2 3 4 5 6 7 8 9 10 11 12 Lemon juice, gastric juice Grapefruit juice, soft drink Tomato juice Human urine Pure water Human blood Seawater Milk of magnesia Household ammonia Household bleach Increasingly ACIDIC (Higher concentration of H + ) NEUTRAL [H + ]=[OH – ] H + H + H + OH – H + H + H + OH – H + H + OH – OH – H + H + OH – OH – OH – H + H + H + OH – OH – OH – OH – OH – OH – H + Increasingly BASIC (Lower concentration of H + ) OH – H + 14 13
    62. 65. <ul><li>Acid precipitation threatens the environment </li></ul><ul><ul><li>Some ecosystems are threatened by acid precipitation </li></ul></ul><ul><ul><li>Acid precipitation is formed when air pollutants from burning fossil fuels </li></ul></ul><ul><ul><ul><li>Combine with water vapor in the air to form sulfuric and nitric acids </li></ul></ul></ul><ul><ul><ul><li>Can kill trees and damage buildings </li></ul></ul></ul>0
    63. 66. Salts <ul><li>Are formed when an acid and a base react with one another neutralizing the concentration of H+ ions </li></ul><ul><li>the process is called neutralization </li></ul>HCl NaOH NaCl + water + = Acid Base Salt + = NaOH Acetic Acid Sodium Acetate + water
    64. 67. Electrolytes <ul><li>are the elements necessary for electrochemical activity in our body. </li></ul><ul><li>Water (H20) – and the three minerals sodium , potassium and chloride are all necessary for the transmission of electrical impulses between cells </li></ul>
    65. 68. THANK YOU. <ul><li>You can print and download this. </li></ul>