Understanding Matter & Elements: Atoms, Bonds, Mass, pH & Molecules

1. Elements • Pure substance that cannotbebrokendown chemically into simpler kinds of matter • More than 100 elements

2. Each element unique chemical symbol • Consists of 1-2 letters • First letter is always capitalized

3. Atoms • The simplest particle of an element that retains all the properties of that element • Our understanding of the structure of atoms based on scientific models, not observation

4. The Protons • All atoms of a given element have the same number of protons • Number of protons called the atomic number • Number of protons balanced by an equal number of negatively charged electrons

5. The Neutrons • The number varies slightly among atoms of the same element • Different number of neutrons produces isotopes of the same element

6. The Electrons • Negatively charged high energy particles • Travel at very high speeds

7. Atomic Mass • The atomic mass of an atom is found by adding the number of protons & neutrons in an atom Periodic Table Elements are arranged by their atomic number(# of protons) on the Periodic Table

9. Compounds A compound is a pure substance made up of atomsoftwoormore elements

10. Molecules are the simplest part of a substance that retains all of the properties of the substance and exists in a free state • Some molecules are large and complex

11. Chemical Formulas • Subscript after a symbol tell the number of atoms of each element • H20 has 2 atoms of hydrogen & 1 atom of oxygen • Coefficients before a formula tell the number of molecules • 3O2 represents 3 molecules of oxygen or (3x2) or 6 atoms of oxygen

12. Covalent Bonds • Formed when two atoms shareone or morepairs of electrons Video

13. Ionic Bonds • Some atoms become stable by losingorgaining electrons • Atoms that lose electrons are called positive ions Video

14. Ions Ions are atoms with either extra electrons or missingelectrons. A normal atom is called a neutral atom. That term describes an atom with a number of electrons equal to the atomic number.

15. pH Scale • logarithmic scale for comparing the relative concentrations of hydronium ions and hydroxide ions in a solution • ranges from 0 to 14 • Each pH is 10X stronger than next • e.g. ph 1 is 10 times stronger than ph 2

16. pH Scale continued An Acid contains an excess of H+hydrogen ions A base contains an excess of OH-hydroxide ions. On the pH scale Acids are 0-6 and Bases are 8-14. What is 7?

17. the lower the pH the stronger the acid • the higher the pH the stronger the base • pH 7.0 is neutral

18. Buffers • Control of pH is very important • Most enzymes function only within a very narrow pH • Control is accomplished with buffers made by the body • Buffers keep a neutral pH (pH 7)

19. Buffers neutralize small amounts of either an acid or base added to a solution • Complex buffering systems maintain the pH values of your body’s many fluids at normal and safe levels

20. Organic vs. Inorganic • Inorganic lack a carbon-hydrogen combination Ex) water, salts (NaCl, KCl) • Organic substances always contain both carbon and hydrogen

21. Macromolecules Carbohydrates Lipids Proteins Nucleic acids

22. Carbohydrates • Elements that make up carbs: C H O; Always 2:1 ratio between H and O • Function of carbs • Main energy source • Structural component: cell walls, insects exoskeleton • Used by cells to recognize other cells: receptors

23. Carbohydrate

25. Monomer of carbohydrates Monosaccharides: onesugar: ex: Glucose, fructose, galactose; chemical formula = C6H12O6 Polymers Disaccharides: twomonomers: ex: sucrose, maltose Polysaccharides: manymonomers: ex: starch, glycogen, cellulose

26. Dehydration Synthesis & Hydrolysis

27. Lipids • Examples: Fats, Waxes and Oils (Mostly C & H); no ratio between H and O • Function of lipids • Stored energy • Structural components

29. Lipids are also made of Monomers: 1 glycerol 3 fatty acids Two types of lipids Saturated: contains max. # H atoms. Unsaturated: contains some C=C bonds.

30. A Representative Fatty Acid

31. Proteins • Elements of proteins: C, H, O, N • Functions • Control rate of reactions • Regulates cell processes (enzymes) • Building materials (collagen & elastin, coloration pigments) • Fight disease (antibodies)

33. Building blocks of proteins • amino acids (AA): are monomers or building blocks of proteins The protein is the Polymers: • proteins are also called polypeptides • One bonded to another AA • Peptide bonds are used to bond one amino acid to another to form proteins AA-AA-AA-AA-AA-AA

34. A large protein chain made of small amino acids http://www.teachertube.com/view_video.php?viewkey=aa818e40a6b8475f0d28 Go to Section:

35. Amino Acids Amino group Carboxyl group General structure Alanine Serine Go to Section:

36. Some Amino Acids

37. Nucleic Acids • Elements of nucleic acids: C, H, O, N, P • Function of nucleic acids • Store & transmit genetic info.; the building blocks to our genetic code (DNA) • Monomers of nucleic acids are called Nucleotides • Three nucleotides of nucleic acids are: • 5-C sugar, Nitrogenous base, phosphate group • Polymer • DNA (deoxyribonucleic acid) • RNA (ribonucleic acid)

38. The 2 Types Of Nucleic Acids 1. DNA (deoxyribonucleic acid)- our hereditary info. • directs all cell activities • 1st identified as double helix 1953 by Watson and Crick 2. RNA (ribonucleic acid)- transcribes hereditary info. (copies DNA) to make a protein the body needs • * this means that proteins determine the nature and activities of the cell

40. The Nucleotide • All nucleotides are identical • The only difference is the type of nitrogenous base they have. • There are 4 types: Guanine, Cytosine, Adenine and Thymine. • These bases pair up in a specific way to make the rungs of the DNA Double Helix.

41. Review Macromolecules • Carbohydrates- • Made up of sugars • Proteins • Made up of amino acids • Lipids • Fatty acid and glycerol • Nucleic acids • Nucleic acids C, H, O, N, P

42. Energy and Chemical Reactions • Living things undergo thousandsofchemicalreactions as part of the life process

43. Certain chemical substances (catalysts) can speed up or slow down a reaction. • Biological catalysts are called enzymes • If it ends in ase it is an enzyme.

44. Enzymes are an important class of catalysts in living organisms • Mostly protein • Thousands of different kinds • Each specific for a different chemical reaction

45. Enzyme Structure • Enzymes work on substances called substrates • Substrates must fit into a place on an enzyme called the active site • Enzymes are reusable! • End in –ase -Sucrase -Lactase -Maltase

46. Enzymes Video

47. Enzyme Active Site • A restrictedregionof an enzyme molecule which bindsto the substrate. Substrate Active Site

48. Enzyme Action • Enzyme-Substrate Complex • substrates – the reacting molecules; the substance(s) that the enzyme works on, • active site– that portion of the enzyme into which the reacting molecules fit • product – the substance that results from the enzymatic activity

49. Lock + Key- refers to how the active site + substrate fits together • there is only one key to a lock • there is only one substrate to an active site

50. Enzyme video • http://bcs.whfreeman.com/thelifewire/content/chp06/0602001.html • Animation