What Are You Worth?

 

LI FE, S HEM I C AL ASI S WhatAre What Are YouWarth YouWarth r l o yw ood hr r k Lecnar d. r C.,frlo sw or t l rS 20mjll .n p. r m ol r e he Yar Yar l ees r l f I i r r cr t l t ot A l er R odf gr r ] : l sw or l l r 2l T m r l l r onper d. . ai e, ar dt heLl r i t edS i ar . t h f l 5 he aver ageea. h. r s wodtr 944, 167e ryear ahe. i i cal l y.l ough.ho\ ough. ho\ 4m 4m L, { : h5 he hum anbod} anbod} r ci l l y t a. h of us t a. ol e.l e.l of of el em eni s r f r l ndr 'r ent al 5ubst ar . esh3t ei r . l r on5i nof onl yon. ki r dof at om .A .A r at om s he sm al i en nr tof tof an el em enthai enthai t l I r cr a'r , 5 t heel em ent e r ol er t r e5 o. . Lt i esspao. es spao.hj hj s m : r , a f d . annotb annotb e br oke.d. w n l r t . s. m et hr nql nql i e r t e: n by

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IMP A C T S , S S E S

Concepts ATOMS NDELEMENTs ND ELEMENTs An elemenl s a ilndamentals bslance rade f one ype oi alom Thealom s he smallesln t of an elemenlthat ti rctalns he elemenlsproperlies, nd ls build buildng ng blocksar blocksar e protons, reclrons, nd neulfons.sotopes realorns realorns l an eLemenlhatvary h atvary n lhe nurnberof eulrons. eulrons.Seclions Seclions 1 2.2 WHYELECTRONS WHY ELECTRONS ATTER Alomsacqu Aloms acqu e share, nd g ve up eleclrons.Whetrrer ne atomw atom w I bondwith ollrers epends n the nlmber and a(angement l lts electrons seclion2 seclion2 3 of at east sorne fthem havevitalfunctions havevitalfunctions.. For nstance, evenalitUe even alitUe selenlum stoxic, but ioolitue cancause can causehean hean problemr and hyroid disorderr. 5up€rficially,hen, h en, he human body canbeviewed can beviewed as a balanced ollectionofelements. ollectionofelements.The Theamounts amounts are areworth worth r o n o ' e { h , n < 1 ' 8 1 .a1d h e i - d s a r e o t e v e ru ru r i q L e . they occurin Earti's crust crust and evenseawater Figure2.1b). propolttorsofelements However,ire However, ire propolttors ofelements n hunans and other orqanisnrs ie unique relative o nonliving lings. Loot at allofthat carbon, or instanc€ instanc€ Alro,you willnever find a clod of dirt or a volumeofseawater hat comes loseto the sttucturctand sttucturct and unctianal organizatio organization n f aliving bady. Assembling hat collectiorofelements collectior ofelements nto an o.ganized, o.ganized, operationalbodytales a fabulousmolecular fabulousmolecular ibiary (DNA), erzymesand erzymes and othermetabolicworlers, metabolicworlers,andlaige,ongojng inputs ofenergy (lust asl anypregiait woman). Rememberhis Remember his when wh en someoneries someoneries o ray"chemistry" ray"chemistry" hasnothing has nothing odowiUr you.lt ha5everlthjng o do Mth you.P€ople,ootfpaste, o otfpaste, urreys, efrigeratorr,et fuel, health,diseare, health, diseare, orsages,cid ain,nerve ain,nervegas, gas,old-growth ndmFany any vrng o. ^onliving 'orests ndmF bit oftle universe ^onlivingbit andchemistry and chemistry s part ofjt.

ATOMS OND T h €b €b o n d i n g e h a v l o rl b o l o g a l m o e c u s s t a r t s t h h e n mb€r and arangemenlol arangemenlol e eclfons n each ypeof ypeof atom. on c, covaenl,and hydrogen onds ondsare are he rnain ategores ol bondsbelween bondsbelween toms n boogica molecules.Seclion molecules.Seclion .4 NOWATER,OLIFE Lileoriginaledn Lileoriginaled n wale ,ands ,ands adapted adapted o ts properties.Water has emperatlre tabiriz g ellects. vanykinds vanykindsof of substances d ssolve asiy n L Waler so shows ohe es sion. ecton25 HYDROGEN Ns RULE L e depends n precis€ ontrols ver he ormat n use and butfering i hydrogen hydrogenons ons Seclon2. Seclon2. 6

i1t EarlierConcepts C oncepts

How Woulil YouVote? YouVote? Fluotide hetpsprcvent hetpsprcvent tooth dacay. But too nuch wrecks banes and teeth, and causes bitth datects A lot can kill yau Many cammunities n the United Statesadd Statesadd rluoride b hen supply ot drinkjng wate. Do you want t in yours? SeeBiologyNow at details, then vote ontine

Wllh hisclrapl€( hisclrapl€(w€ w€ stanal he baseol baseol liles liles eve eves s oi ofganizal n so ake a rnornenlo revew revew lre simpe simpe clrart in secrio " lr all sra.rsw Ih arors a-d ._erSy L:le< organizalloncquiros cquirosapping apping ntoa nto a grealone-way one-waylo lo w oi enerqy enerqy nd stoing r n bonds bondsberween berween rorns 1.2). The chapteraso Thechapter aso hasa has a simpleexampe simpleexampeof of howthe body'sblilt-in body's blilt-inrnechanismse rnechanismse p rel rn he nlernal env onrnenlo onrnenlo a homeostatic homeostaticlate latewh€n wh€ncondilons condilons shilrb€yonclranges shilr b€yonclrangeshat hatce ce s can o erate 1.2)