the dirty little secret about Biology Chemistry the dirty little secret about Biology

(wait, isn’t that Biology?) Chemistry Chemicals are the stuff that make up our bodies, the bodies of other organisms, and the physical environment. (wait, isn’t that Biology?) © 2012 Pearson Education, Inc.

Water Life’s chemistry is tied to water. Life first evolved in water. All living organisms require water. The chemical reactions of your body occur in cells consisting of 70–95% water. © 2012 Pearson Education, Inc.

Matter anything that occupies space and has mass composed of elements cannot be broken down into other substances 92 in nature; scientists have created 26 more created elements too unstable to occur naturally you ARE chemistry chemistry is your friend! © 2012 Pearson Education, Inc.

Atoms smallest unit of matter that still retains properties of that element (fxnal unit of matter) nucleus protons (positive charge) neutrons (no charge) orbital shell electrons (negative charge and hardly any weight) opposites attract © 2012 Pearson Education, Inc.

Helium Nucleus 2e Electron cloud 2 Protons Mass number  4 Neutrons Figure 2.3A Helium Nucleus Electron cloud 2 Protons Neutrons Electrons Mass number  4 2e Figure 2.3A Two models of a helium atom 6

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http://www. google. com/imgres. imgurl=http://www. classzone http://www.google.com/imgres?imgurl=http://www.classzone.com/books/earth_science/terc/content/investigations/es0501/images/es0501_p6_readinginfo_b.gif&imgrefurl=http://www.classzone.com/books/earth_science/terc/content/investigations/es0501/es0501page06.cfm&usg=__Px06U8z6IBfQlwNWxuoI82oO_k4=&h=410&w=550&sz=30&hl=en&start=1&zoom=1&tbnid=tKy18DAObylfeM:&tbnh=99&tbnw=133&ei=4hODTrKMM8S5tgemvYTkAQ&prev=/search%3Fq%3Dperiodic%2Btable%2Bwith%2Bexplanation%26hl%3Den%26gbv%3D2%26tbm%3Disch&itbs=1

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Carbon Electron cloud 6e Nucleus 6 Protons Mass number  12 6 Figure 2.3B Carbon Electron cloud 6e Nucleus Figure 2.3B Model of a carbon atom 6 Protons Mass number  12 6 Neutrons 6 Electrons 10

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http://terra. dadeschools http://terra.dadeschools.net/Books/Biology/BiologyExploringLife04/0-13-115075-8/text/chapter4/04images/04-05.gif

Isotopes: Medical Uses Living cells cannot distinguish between isotopes of the same element. Therefore, radioactive compounds in metabolic processes can act as tracers. This radioactivity can be detected by instruments. Using these instruments, the fate of radioactive tracers can be monitored in living organisms. © 2012 Pearson Education, Inc.

Figure 5.3 Radioisotopes Are Useful in Medical Imaging (a) The thyroid gland, located in the neck, helps regulate metabolism. The element iodine accumulates in the gland and is necessary for normal thyroid function. (b) This image is a visualization of the thyroid gland in a patient with goiter, an enlargement of the thyroid gland, often caused by iodine deficiency. Small amounts of radioactive iodine were given to the patient, and the accumulated radioisotope was visualized with a gamma-ray scan.

Chemical Bonds electrons: the only part of an atom that interact arranged in shells around the nucleus have one, two or three electron shells have to fill the 1st shell then get a 2nd shell have to fill the 2nd shell, then get a 3rd shell http://www.btinternet.com/~chemistry.diagrams/electron-shells.gif © 2012 Pearson Education, Inc.

Chemical Bonds # of shells determined by # of protons Figure 2.5_1 Chemical Bonds Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminum Silicon Phosphorus Sulfur Chlorine Argon Figure 2.5_1 The electron distribution diagrams of the first 18 elements in the periodic table # of shells determined by # of protons atoms want the outermost shell to be filled =STABILITY 18

Sodium Chlorine Sodium chloride Figure 2.1 Figure 2.1 The emergent properties of the edible compound sodium chloride Sodium Chlorine Sodium chloride 19

Chemical Bonds: 3 Types Ionic: gaining or losing of electrons NaCl excellent example Na+ has 1 e- in its outer shell (how many needed to be stable?) Cl- has 7 e- in its outer shell http://upload.wikimedia.org/wikipedia/commons/5/56/Electron_shell_017_chlorine.png http://www.google.com/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons/4/47/Electron_shell_011_sodium.png&imgrefurl=http://la.wikipedia.org/wiki/Fasciculus:Electron_shell_011_sodium.png&usg=__4F00tRgPNZDAYfGI9xN5lscHFWs=&h=1835&w=1678&sz=105&hl=en&start=1&zoom=1&tbnid=MYjB82CBG92KJM:&tbnh=150&tbnw=137&ei=oyODTuShJ-Xt0gH_ovGcAQ&prev=/images%3Fq%3Dsodium%2Belectron%2Bshells%26um%3D1%26hl%3Den%26gbv%3D2%26tbm%3Disch&um=1&itbs=1

Figure 5.6 Ions Are Created through the Loss or Gain of Electrons Negatively charged ions are often given special names, such as “chloride” for the chlorine ion (Cl−) and “fluoride” for the fluorine ion (F−).

Na Sodium atom Cl Chlorine atom Na Sodium ion Cl Chloride ion Figure 2.7A_s2 Transfer of electron Na Sodium atom Cl Chlorine atom Na Sodium ion Cl Chloride ion Figure 2.7A_s2 Formation of an ionic bond, producing sodium chloride (step 2) Sodium chloride (NaCl) 23

Now both Na+ and Cl- have filled their outer shells = STABILITY!!! they are ALSO both charged now b/c they have an electron/proton imbalance

Ionic Bonds: opposites attract WEAK: toss in water and dissolve-why?

WATER is POLAR!!!! http://web.virginia.edu/Heidi/chapter2/chp2.htm

Ionic Bonds Synonyms: Similar to ‘dating’ Ca++ means what? salt electrolyte Similar to ‘dating’ Ca++ means what? PO43- means what?

Covalent Bonds e- are shared: they orbit around nuclei of both atoms involved in the bond very strong bond: takes NRG to create releases NRG when broken MARRIAGE!!!

http://alevelnotes.com/Bonding/130

http://www.school-for-champions.com/chemistry/bonding_types.htm http://www.tutorvista.com/content/chemistry/chemistry-i/chemical-bonding/triple-covalent-bond.php

Covalent Bonds all compounds are molecules, two or more atoms joined together = Molecule two or more types of atoms joined together = Compound all compounds are molecules, BUT not all molecules are compounds

Table 2.6 Table 2.6 Alternative ways to represent four common molecules 32

nonpolar: equal sharing of e- http://www.school-for-champions.com/chemistry/bonding_types.htm nonpolar: equal sharing of e-

Figure 2-5 Polar Covalent Bonds and the Structure of Water Hydrogen atom Oxygen atom 2  Polar: UNequal sharing of e- due to difference in pull from nucleus © 2012 Pearson Education, Inc. 34

Hydrogen Bonds: weak but IMPORTANT!!! http://www.elmhurst.edu/~chm/vchembook/162othermolecules.html http://www.dna-sequencing-service.com/dna-sequencing/dna-hydrogen-bonds-2/

Chemical Reactions Interactions between atoms making bonds (stores NRG) breaking bonds (releases NRG) chemical rxns do not create or destroy matter rearrange matter rxns of life generally require enzymes NRG not created or destroyed