The Chemistry of Life Elements and Water

1. The Chemistry of LifeElements and Water

2. Matter and Atoms • Matter is any material that has mass and occupies space. • All materials nonliving and living in the universe is composed of matter. • All matter is composed of small units called atoms. The types of atom, their arrangement, and how they interact with one another gives the type of matter its specific chemical and physical properties.

3. Atoms are composed of subatomic particles each with their own unique properties. They are: a. Protons - Positive charge, atomic mass unit of one. Gives the atom its identity (Atomic Number). Located in the nucleus or center of the atom. b. Neutrons – No charge (neutral), atomic mass unit of one. Their numbers can vary from atom to atom of the same element. Responsible for forming isotopes. Located in the nucleus. c. Electrons - Negative charge, no atomic mass unit. Located outside of nucleus in regions called orbitals. They are involved with the process of chemical bonding between atoms. - can be shared or transferred between atoms in the bonding process therefore, their numbers can vary between atoms of the same element. - If atoms gain or lose electrons they become electrically charged and are called ions. They are responsible for the reactive chemical properties of atoms.

4. Basic Atom Structure Neutron No charge Amu 1 Proton + charge Amu 1 electron orbital • Electron • Charge • Amu 0 Nucleus composed of protons and neutrons. Gives the atom its atomic mass, determined by adding the number of protons and neutrons together.

5. Periodic Table of Elements • Element is a pure substance made up of one type of atom. • Elements which are most common in all living things are • Hydrogen (atomic number 1), Carbon (atomic number 6), • Nitrogen (atomic number 7), and Oxygen (atomic number 8). • These compose the backbone or framework of the molecules such as proteins, lipids, nucleic acids, and carbohydrates found in living things.

6. Hydrogen, Carbon, and Oxygen

7. Other Biologically Important Elements • Calcium (Ca): Formation of bones and shells in animals, involved with muscle contraction and neuron activity in animals. • Phosphorous (P): Forms energy storing compounds ATP, Nucleotides (A,T, G, C, U), and membrane building molecules (phospholipids). • Sulfur (S): amino acids and protein structure • Sodium (Na): Neuron activity, water balance, and membrane transport • Potassium (K): membrane transport and muscle activity • Iron (Fe): oxygen transport of red blood cells as a component of hemoglobin. • Magnesium (Mg): light activated atom component of chlorophyll molecules.

8. Chemical Bonding Review Chemical bonds form to • increase the stability of atoms by filling their outer most electron energy level. • to do this atoms will transfer electrons ( one atom will lose electrons and the other atom will gain electrons) to form ionic bonds • or atoms will share a pair of electrons (each atom will share one electron for each bond that is created between them) to form covalent bonds.

9. Na Sodium (Na) 11 Chlorine (Cl) 17 Ionic Bonding In order to increase stability, the Na atom will transfer its outermost electron to the Cl atom. Outermost Energy Levels Na Cl Cl Chlorine (Cl) 17 Sodium (Na) 11 Protons 11 17 11 17 Neutrons 12 18 12 18 Electrons 11 17 10 18 Charge Neutral Neutral positive negative Ion Neutral Neutral cation anion Stability is achieved because the outer energy levels of both atoms, now ions are filled by electrons.

10. H C C C C H H H H Covalent Bonding Each pair of electrons represents the formation of a covalent bond. Hydrogen (H) 1 Carbon (C) 4 Methane CH4 Stability is again achieved because the outer energy levels of both atoms, now the outer energy levels are filled by electrons due to sharing of electron pairs between the atoms!

11. Periodic Table of the Elements

13. Five Major Elements in Humans • Oxygen O 65% • Carbon C 19% • Hydrogen H 10% • Nitrogen N 3% • Calcium Ca 2% • Trace Elements • Fe, Zn, Mg, Cu 1%

14. Water • 60 -70% Body Mass • Polar Molecule • Solvent • Reactant / Decomposition Reactions • Cohesive Properties • Surface Tension • Temperature Buffer • Thermal Conductance

15. Water Molecule Structureand Hydrogen Bonding Covalent bonds between H and O Positively charged hydrogen end Hydrogen Bonds Negatively charged oxygen end

16. How Hydrogen Bonds Work • the positive region of one molecule becomes attracted to the negatively charged region of another molecule forming Hydrogen Bonds. • So, the molecules “stick” together  weakly

20. Water • Water is a molecule that is essential to life as we know it here on Earth. It is a component of all living things and serves many functions. Water has many unique properties due to the nature of its molecular composition. • Water is a polar covalent substance. Although it is formed by covalent bonds between two atoms of hydrogen and one oxygen atom, there is an unequal sharing of electrons between the two types of atoms. • Oxygen is a larger molecule and has a higher attraction for hydrogen atoms. So, electrons tend to be around the oxygen atom than the hydrogen atoms. • This results in a slightly negatively charged region of the molecule where the oxygen atom is located and a slightly positively charged region of the molecule where the hydrogen atoms are located. • This produces polarity in the molecule and leads to some unique properties of water.

21. Important Properties of Water • High specific heat: It requires much heat energy to raise the temperature of water one degree Celsius. Important in regulating the temperature of living things. This results in a HIGH HEAT OF VAPORAIZATION • This creates a HEAT BUFFER – maintaining homeostasis. • High heat capacity: It requires a long period of time for water to gain or lose heat energy. Important in regulating temperature, important to aquatic organisms. • Universal Solvent: Many materials organic and inorganic will dissolve in water. Important in the role as a transport medium for living things. Animal blood and the sap of plants are primarily composed of water with other materials dissolved in it.

22. Important Properties of Water • Cohesive properties: Water molecules hydrogen bond together to form a “film” layer on the surface of water called surface tension, capable of supporting certain plants and animals. This property also plays a role in capillary action (the movement of water up and through small diameter tubes). • Adhesive properties: Water molecules due to their polar nature tend to stick to other substances. This property along with cohesion is responsible for capillary action and the formation of a meniscus in a glass tube.

23. Finally • Water Expands as It Freezes: The solid form of water is less dense than the liquid, therefore ice floats! • Most dense at 4 degrees Celsius • This is important in aquatic environments because they will always freeze from the top surface down. The ice usually creates an insulating layer from the colder air temperature, allowing the organisms below the surface of the ice to survive. • However, this property is also dangerous to organism with soft tissues. When the water inside their cells freeze, it expands and destroys the cells. Frost bite in humans is a result of this property.

24. Acids, Bases, and Salts • Acid  H+ • Base  OH- • Salts  Anything not an acid or base 2HCl  2H+ + Cl2 NaOH  Na + OH- 2NaCl  2Na + Cl2

25. limited H2O H+ + OH- 2 H2O H30+ + OH- hydronium hydroxyl ion ion Ionization of Water Although water is essentially neutral, it can ionize to a certain extent:

26. HCl H+ + Cl- Ionization of Acids in Water Acids are substances that dissociate to release H + ions limited Examples of strong acids include stomach acid (HCl), lemon juice, orange juice

27. NaOH Na+ + OH- Ionization of Bases in Water Bases are substances that release OH – Ions into solution limited Examples of bases include Baking soda, antacids, household ammonia

28. pH = - log[H+]

29. Calculating pH pH = -log[H+] So if [H+] = 1 X 10 – 6 ------> pH 6 [H+] = 1 X 10 – 5 ------> pH 5 [H+] = 1 X 10 – 2 ------> pH 2

31. Litmus Test for Acids The presence of an acid turns blue litmus paper red

32. Litmus Test for Bases The presence of a base turns red litmus paper blue

33. What is Litmus anyways?? • a pigment from lichens that turns red in acid solutions and blue in alkaline solutions • It is used as a very simple acid-base indicator

34. Is Your pH Off Balance? • Rings Turn Fingers Green • Heartburn • Bloating • Belching • Feeling Full after Eating Small Amounts • Insomnia • Water Retention • Migraines • Constipation • Diarrhea • Fatigue • Burning Sensation on Tongue or in Mouth • Halitosis

35. “Modern agriculture and food-preservation methods have done serious damage to the human diet. The detrimental effects on the human body caused by acidic wastes from processed food and chemical additives are myriad. Byproducts of the foods we eat, acidic wastes are the common denominator in all degenerative diseases. When acidic wastes accumulate, they can cause organs to malfunction and degenerate. Balancing the body's acid-alkaline pH factor is a dynamic way to improve health. “ Felicia Drury Kliment

36. pH Buffer • Stabilizes the pH level if acids or bases are introduced to a solution Example • Blood if filled with buffers to resist changes in pH CO2 + H2O(Blood)  HCO3-1