Pop Quiz. Bio 105: Chemistry. Chemistry. Outline. Elements in Nature. Chemistry Matter Anything that takes up space and has mass 1/27/2016

Transcription

1 Pop Quiz Bio 105: hemistry Lecture 2 Reading: hapter 2 (Pages 20-39) Name four common characteristics of living organisms. All the factors in an experiment that are kept the same in the experiment (water, cages, etc) are called the. What domain and kingdom do humans belong to? 1 opyright 2009 Pearson Education, Inc. 2 opyright 2009 Pearson Education, Inc. Outline Why study chemistry Elements Atoms, Isotopes, Periodic Table, Electrons and Bonding Bonds ovalent Bonds (Polarity), Ionic Bonds, ydrogen Bonding Water Acids and Bases hemistry Basis for studying much of biology Biology of the human body follows the rules of physics and chemistry Examples: What can cross a membrane? What biological compounds make up cells? What are the structures within the cells? What is a protein? 3 opyright 2009 Pearson Education, Inc. 4 opyright 2009 Pearson Education, Inc. hemistry Matter Anything that takes up space and has mass Elements in Nature Atoms Units of matter that cannot be broken down into simpler substances Element A pure form of matter containing only one kind of atom 5 opyright 2009 Pearson Education, Inc. 6 opyright 2009 Pearson Education, Inc. 1

2 Periodic Table of Elements Important Elements in the uman Body 7 opyright 2009 Pearson Education, Inc. 8 opyright 2009 Pearson Education, Inc. Atom Subatomic Particles omposed of parts Protons arry a positive charge (+) Neutrons arry no charge (neutral) Electrons arry a negative charge (-) 9 opyright 2009 Pearson Education, Inc. 10 opyright 2009 Pearson Education, Inc. Atom Examples of Atoms 11 opyright 2009 Pearson Education, Inc. 12 opyright 2009 Pearson Education, Inc. 2

3 Where is elium? Oxygen 13 opyright 2009 Pearson Education, Inc. 14 opyright 2009 Pearson Education, Inc. Shell Model of Electrons Number of electrons per shell 1 st shell: 2 2 nd shell: 8 3 rd shell: 8 4 th shell: 8 Where are protons found? ow many electrons can be in the 1 st shell? ow many electrons can be in the 2 nd shell? 15 opyright 2009 Pearson Education, Inc. 16 opyright 2009 Pearson Education, Inc. Periodic Table of Elements Simplified Periodic Table 17 opyright 2009 Pearson Education, Inc. 18 opyright 2009 Pearson Education, Inc. 3

4 Periodic Table of Elements Atomic Number # of protons in an atom Remember Atoms have equal number of protons and electrons It is also the number of electrons Particle Mass Proton = 1 amu Neutron = 1 amu Electron = negligible 19 opyright 2009 Pearson Education, Inc. 20 opyright 2009 Pearson Education, Inc. Periodic Table of Elements ow many electrons does Be have? Isotopes Atoms with the same number of protons but different numbers of neutrons are called isotopes 21 opyright 2009 Pearson Education, Inc. 22 opyright 2009 Pearson Education, Inc. Radioactive Isotopes 1896, enri Becquerel Rock containing uranium Marie urie (coworker) named this radioactivity Known as a radioisotope Radioactive Isotopes Radioisotopes Unstable Become more stable by emitting energy and particles 23 opyright 2009 Pearson Education, Inc. 24 opyright 2009 Pearson Education, Inc. 4

5 Radioisotopes in Medicine Isotopes in Medicine PET Scans (Positron-Emission Tomography) Image From: nutrition/way-exploit-metabolic-quirk-cancer Image From: 25 opyright 2009 Pearson Education, Inc. 26 opyright 2009 Pearson Education, Inc. Isotopes are atoms of the same element that differ in their number of. arbon has 6 protons, 6 electrons and 6 neutrons. Its atomic number is. arbon has 6 protons, 6 electrons and 6 neutrons. Its atomic weight is. a) Six b) Eight c) Twelve d) Twenty-Four 27 opyright 2009 Pearson Education, Inc. 28 opyright 2009 Pearson Education, Inc. Mass Number & Atomic Weight Atomic Weight An average of the isotopes Mass Number Atomic number Atomic weight Round the atomic weight to the nearest whole number Mass Number = (# of Protons) + (# of Neutrons) Number of Neutrons = Mass Number # of Protons Mass Number & Atomic Weight For any element # of Protons = Atomic Number # of Electrons = # of Protons = Atomic Number # of Neutrons = Mass Number Atomic Number 29 opyright 2009 Pearson Education, Inc. 30 opyright 2009 Pearson Education, Inc. 5

6 Mass Number & Atomic Weight For Be: # of Protons = Atomic Number = # of Electrons = # of Protons = # of Neutrons = Mass number Atomic Number= arbon has 6 protons, 6 electrons and 6 neutrons. Its atomic weight is. a) Six b) Eight c) Twelve d) Twenty-Four 31 opyright 2009 Pearson Education, Inc. 32 opyright 2009 Pearson Education, Inc. hemical Bonds Bonds are unions between electron structure from different atoms Molecules Same element ( 2 ) Different element ( 2 O) ompound Molecule 33 opyright 2009 Pearson Education, Inc. 34 opyright 2009 Pearson Education, Inc. Outer Shell Electrons & Bonding Full = non-reactive and stable Does not form chemical bonds Incompletely full = reactive Will form chemical bonds Number of bonds it can form depends on how many empty spots are in outer shell Don t Forget Shell Model of Electrons Number of electrons per shell 1 st shell: 2 2 nd shell: 8 3 rd shell: 8 4 th shell: 8 35 opyright 2009 Pearson Education, Inc. 36 opyright 2009 Pearson Education, Inc. 6

7 Periodic Table of Elements Review Question ow many neutrons does Li have? 37 opyright 2009 Pearson Education, Inc. 38 opyright 2009 Pearson Education, Inc. hemistry & Biology hemical Bonds 3 types ovalent Bonds Ionic Bonds ydrogen Bonds 39 opyright 2009 Pearson Education, Inc. 40 opyright 2009 Pearson Education, Inc. Strongest bonds ovalent Bonds hemical Bonds Each atom wants their outer shell filled ydrogen arbon 41 opyright 2009 Pearson Education, Inc. 42 opyright 2009 Pearson Education, Inc. 7

8 Let s look at arbon Oxygen ovalent Bonds Double Bond 43 opyright 2009 Pearson Education, Inc. 44 opyright 2009 Pearson Education, Inc. ow many bonds can carbon form? ow many bonds can hydrogen form? 45 opyright 2009 Pearson Education, Inc. 46 opyright 2009 Pearson Education, Inc. ow many bonds can helium form? ow many bonds can nitrogen form? 47 opyright 2009 Pearson Education, Inc. 48 opyright 2009 Pearson Education, Inc. 8

9 ow many bonds can oxygen form? Types of ovalent Bonds 2 atoms with unpaired electrons in the outer shell come together and share electrons Polar Nonpolar 49 opyright 2009 Pearson Education, Inc. 50 opyright 2009 Pearson Education, Inc. ovalent Bonds - Nonpolar ovalent Bonds - Polar 51 opyright 2009 Pearson Education, Inc. 52 opyright 2009 Pearson Education, Inc. ovalent Bonds - Polarity Some atoms have a greater pull on shared electrons than other atoms Electronegativity Bond between atoms with different electronegativities = polar bond ovalent Bonds - Polarity Polar ovalent Bonds Strong electrophiles (electronegative) ommon examples for biological molecules Oxygen Nitrogen Sulfur 53 opyright 2009 Pearson Education, Inc. 54 opyright 2009 Pearson Education, Inc. 9

10 ovalent Bonds - Polarity ovalent Bonds - Polarity Water O O Alcohol Ketone O O Aldehyde ydrocarbons opyright 2009 Pearson Education, Inc. 56 opyright 2009 Pearson Education, Inc. 57 ovalent Bonds - Polarity N opyright 2009 Pearson Education, Inc. 3 S 3 opyright 2009 Pearson Education, Inc. Polar Groups Oxygen ontaining arboxyl (-OO) ydroxyl (alcohol) (-O) Phosphates (-PO 4 ) arbonyl Ketone (-O) Aldehyde (-O) Nitrogen ontaining Amino (-N 2 ) Sulfur ontaining (-S) 58 arboxyl Nonpolar ompounds Alcohol 322O ydrocarbons Ketone Aldehyde Ether 3-O-23 ydrocarbons 323 opyright 2009 Pearson Education, Inc. 60 opyright 2009 Pearson Education, Inc. 10

11 ydrophilic Polar VS Nonpolar Water loving Polar Molecules ydrophobic Water fearing Nonpolar molecules ompounds hemical Formulas Write it as a formula to tell us how many atoms of each element are present Not how they molecule is put together 61 opyright 2009 Pearson Education, Inc. 62 opyright 2009 Pearson Education, Inc. 2 O ow would you draw this compound? 4 10 ow would you draw this compound? 63 opyright 2009 Pearson Education, Inc. 64 opyright 2009 Pearson Education, Inc. ow would you draw this compound? ow would you draw this compound? 4 8 O 2 65 opyright 2009 Pearson Education, Inc. 66 opyright 2009 Pearson Education, Inc. 11

12 2 4 O ow would you draw this compound? TE END for today Image From: 67 opyright 2009 Pearson Education, Inc. 68 opyright 2009 Pearson Education, Inc. hemistry Review Atomic Number = # of electrons # of electrons = # of protons Atomic Weight Average weight of all naturally occurring isotopes Mass Number Atomic Weight rounded to nearest whole number (# of protons) + (# of neutrons) OR # of neutrons = Mass # - (# of protons) Electron Orbitals hemistry Review 1 st shell: 2 2 nd shell: 8 3 rd shell: 8 4 th shell: 8 Remember Atoms want their orbital shells to be full 69 opyright 2009 Pearson Education, Inc. 70 opyright 2009 Pearson Education, Inc. hemistry Review ow many electrons? ow many protons? ow many neutrons? What is the atomic weight? What is the mass #? ow many bonds does an atom of this element want to form? hemical Bonds Three types of chemical bonds ovalent Bonds ydrogen Bonds Ionic Bonds 71 opyright 2009 Pearson Education, Inc. 72 opyright 2009 Pearson Education, Inc. 12

13 Weak affection ydrogen Bonding ydrogen atom (partial positive) Partial negative charged atom Individually vs Many Together Determines shapes for many biological molecules (including proteins and DNA) ydrogen Bonds 73 opyright 2009 Pearson Education, Inc. 74 opyright 2009 Pearson Education, Inc. Ionic Bonds Ionic Bonds Ion Atom that has gained or lost electrons What is an ionic bond? 75 opyright 2009 Pearson Education, Inc. 76 opyright 2009 Pearson Education, Inc. Ionic Bond hemical Bonds 77 opyright 2009 Pearson Education, Inc. 78 opyright 2009 Pearson Education, Inc. 13

14 Water The Life Giving Molecule Water s Abundance % of Earth s surface is water 66% of the human body is water by weight 75-85% of a cell s weight is water 79 opyright 2009 Pearson Education, Inc. 80 opyright 2009 Pearson Education, Inc. What do we know about water? ydrogen Bonding What is it made of? Is it polar or non-polar? What kind of bonds can it form? O O 81 opyright 2009 Pearson Education, Inc. 82 opyright 2009 Pearson Education, Inc. Water Water Exists in 3 forms Solid (ice) Liquid Vapor 83 opyright 2009 Pearson Education, Inc. 84 opyright 2009 Pearson Education, Inc. 14

15 Water There are 4 properties of water Water is an excellent polar solvent Water has cohesion Water has high heat capacity Water has high heat of vaporization Water An excellent polar solvent Acts as a solvent for polar molecules Like dissolves in like onsidered to be the best polar solvent 85 opyright 2009 Pearson Education, Inc. 86 opyright 2009 Pearson Education, Inc. Water As a solvent Water as a solvent 87 opyright 2009 Pearson Education, Inc. 88 opyright 2009 Pearson Education, Inc. Water as a solvent Why is this important? Blood is 55% water ells are made up of mainly water (75-85%) Water keeps salts in your cells, blood and tissues in solution (dissolved) Water has ohesion Due to hydrogen bonding Water molecules cling together ohesion the capacity to resist breaking under tension Image from: 89 opyright 2009 Pearson Education, Inc. 90 opyright 2009 Pearson Education, Inc. 15

16 Water has ohesion Why is this important? Allows blood to move easier in the blood vessels Responsible for moving water in plants Water has high heat capacity Requires great deal of energy to raise the temperature of water as compared to other compounds Example a non-polar molecules like methane takes very little energy to heat up 91 opyright 2009 Pearson Education, Inc. 92 opyright 2009 Pearson Education, Inc. Water has high heat capacity Why is this important? Keeps us at a constant temperature Water has high heat of vaporization Takes a great deal of energy to make water evaporate What is this important? Sweat allows us to cool of 93 opyright 2009 Pearson Education, Inc. 94 opyright 2009 Pearson Education, Inc. 2 is a(n). ydrophobic molecules are by water What type of bond between water molecules creates surface tension that gives water cohesion? an water make ionic bonds? Is water polar or non polar? Name the property of water that provides the cooling effect of sweating. Acids and Bases We are already familiar with acids and bases Lemon juice? Soda? Ammonia? Bleach? Vinegar? ousehold cleaners? 95 opyright 2009 Pearson Education, Inc. 96 opyright 2009 Pearson Education, Inc. 16

17 Acids and Bases Depends what the substance does with its hydrogen ions Acids Donate hydrogen ions in solution Bases Accept hydrogen ions in solution Or say that bases release O- (hydroxyl ions) Acid Example: l + + l - Acids and Bases Base Example: NaO Na + + O - Water and Salt 2 O + Nal + + l - + Na + + O - 97 opyright 2009 Pearson Education, Inc. 98 opyright 2009 Pearson Education, Inc. p Scale Used to measure the strength of acids and bases p = -log 10 [ + ] [ + ] = oncentration in moles per Liter (L) Inverse relationship Logarithmic p Scale Ranges from 0 to 14 7 is neutral Pure water What is the most acidic? What is the most basic? 99 opyright 2009 Pearson Education, Inc. 100 opyright 2009 Pearson Education, Inc. p Scale p Scale 101 opyright 2009 Pearson Education, Inc. 102 opyright 2009 Pearson Education, Inc. 17

18 p Scale p Scale 103 opyright 2009 Pearson Education, Inc. 104 opyright 2009 Pearson Education, Inc. The higher the p a solution has, the higher the + concentration. True/False Is a p of 8 acidic or basic? Biological Fluids Blood p 7.35 hanges in p of +/- 0.1 can damage cells p of 7.8 can be lethal Biological Fluids ave buffers to keep p stable Most between 6 to 8 Stomach fluid p of under opyright 2009 Pearson Education, Inc. 106 opyright 2009 Pearson Education, Inc. Resist p changes Buffers + or O - Body wants to keep its fluids at an even p Blood contains buffers Weak acids Example: Buffers arbon dioxide enters the blood and combines with water 107 opyright 2009 Pearson Education, Inc. 108 opyright 2009 Pearson Education, Inc. 18

19 Important oncepts What are the 3 particles of an atom? Where are they located? What is their charge? What is their mass? Be able to determine how many bonds each element can form. Be able to recognize if a molecule is drawn correctly 109 opyright 2009 Pearson Education, Inc. 110 opyright 2009 Pearson Education, Inc. Important oncepts Be able to read the periodic table to determine the # of protons, neutrons and electrons Be able to do this for all of the biologically important elements What are the 3 most common elements in the human body? Be able to draw the atom of any biologically important element With correct number of protons, neutrons and electrons Be able to draw the electrons in their correct shell Be able to identify polar and non polar molecules Important oncepts Be able to describe the types of chemical bonds What are 3 electronegative elements found in biological molecules? Be able to draw a water molecule and hydrogen bonding between water molecules Be able to describe the 4 properties of water and their importance in living organisms. Understand the p scale 111 opyright 2009 Pearson Education, Inc. 112 opyright 2009 Pearson Education, Inc. Definitions The End Matter Atom Elements Isotopes Radioisotopes hemical bonds Single bond Double bond Molecules ompound Molecules Ion Ionic bond ovalent bond Nonpolar bonds Polar bonds Eletronegativity ydrogen bond ydrophilic ydrophobic ohesion Acid base Buffers Logarithmic Inverse p Solvent Solute Solution Image From: opyright 2009 Pearson Education, Inc. 114 opyright 2009 Pearson Education, Inc. 19