The Chemistry of Life What are living creatures made of? Why do we have to eat?
96% of living organisms is made of: carbon (C) oxygen (O) hydrogen (H) nitrogen (N) Elements of Life
Molecules of Life Put C, H, O, N together in different ways to build living organisms What are bodies made of? –carbohydrates sugars & starches –proteins –fats (lipids) –nucleic acids DNA, RNA
Carbohydrates
Sugars = building blocks Names for sugars usually end in –glucose –fructose –sucrose –maltose OH H H HO CH 2 OH H H H OH O glucose C 6 H 12 O 6 sucrose fructose maltose -ose
Sugar Has Many Disguises Careful reading of labels is necessary to know how much added sugar you are getting. Sometimes sugar masquerades as apparently more “healthy” ingredients, Here is a list of some of the possible code words for “sugar” which may appear on a label. Hint: the words “syrup”, “sweetener”, and anything ending in “ose” can usually be assumed to be “sugar”. Agave NectarAgave Nectar Maltodextrin Barley Malt Syrup Malt syrup Corn sweetener Maltose Corn syrup, or corn sugar Maple syrup Dehydrated Cane Juice Molasses Dextrin Raw sugar Dextrose Rice Syrup FructoseFructose Saccharose Fruit juice concentrate Sorghum or sorghum syrup Glucose Sucrose High-fructose corn syrup Syrup Honey Treacle Invert sugar Turbinado Sugar Lactose Xylose
Carbohydrates: OH H H HO CH 2 OH H H H OH O Energy molecules
sucrose Carbohydrates Function: –quick energy –energy storage –structure Example –sugars –starches –cellulose (cell wall) glucose C 6 H 12 O 6 starch
Carbohydrates Building block molecules = sugar sugar - sugar - sugar - sugar - sugar Simple sugars
BIG carbohydrates Starch –energy storage in plants potatoes Glycogen –energy storage in animals in liver & muscles Cellulose –structure in plants cell walls Chitin –structure in arthropods & fungi exoskeleton
Building BIG carbohydrates glucose + glucose + glucose… = starch (plant) glycogen (animal) energy storage polysaccharide
Digesting starch vs. cellulose starch easy to digest cellulose hard to digest enzyme
Cellulose Cell walls in plants –herbivores can digest cellulose –most carnivores cannot digest cellulose that’s why they eat meat to get their energy & nutrients cellulose = roughage
Cow can digest cellulose well; no need to eat other sugars Gorilla can’t digest cellulose well; must add another sugar source, like fruit to diet
Helpful bacteria How can cows digest cellulose? –bacteria live in their stomachs & help digest cellulose-rich (grass) meals
Building carbohydrates Synthesis | glucose | glucose monosaccharides 2 sugars = disaccharide | maltose
Lipids: Fats & Oils
Lipids Examples –fats –oils –waxes –hormones sex hormones –testosterone (male) –estrogen (female)
Lipids Function: –energy storage very concentrated twice the energy as carbohydrates! –cell membrane –cushions organs –insulates body think whale blubber!
Molecular Structure of Fat not a chain (polymer) = just a “big fat molecule”
Lipids Concentrated energy molecules
Other lipids in biology Cholesterol –good molecule in cell membranes –make hormones from it including sex hormones –but too much cholesterol in blood may lead to heart disease
Other lipids in biology Cell membranes are made out of lipids –phospholipids –heads are on the outside touching water “like” water –tails are on inside away from water “scared” of water –forms a barrier between the cell & the outside
Saturated fats Most animal fats –solid at room temperature Limit the amount in your diet –contributes to heart disease –deposits in arteries
Unsaturated fats Plant, vegetable & fish fats –liquid at room temperature the fat molecules don’t stack tightly together Better choice in your diet
Saturated vs. unsaturated saturatedunsaturated
Trans fats → Hydrogenation
Trans Fatty Acids Hydrogenated & Partially Hydrogenated Oils: Proven Serious Health Effects After closely analyzing data from scientific studies and reviews, many countries (in our country many states) have either banned hydrogenated and partially hydrogenated oils altogether or have instituted future dates for elimination of their use in foods. These government actions concerning the trans fatty acids (hydrogenated and partially hydrogenated oils) is directly related to studies that link trans fatty acid (hydrogenated and partially hydrogenated oil) consumption from processed foods to the development of diabetes, cancer and cardiovascular disease.
Proteins
Proteins: Multipurpose molecules
Proteins Building block = amino acid amino acid – amino acid – amino acid – amino acid – —N——N— H H H | —C— | C—OH || O variable group amino acids 20 different amino acids
Amino acid chains Proteins –amino acids chained into a polymer Each amino acid is different some “like” water & dissolve in it some “fear” water & separate from it
Its shape that matters! Proteins do their jobs, because of their shape Unfolding a protein destroys its shape –wrong shape = can’t do its job –unfolding proteins = “denature” temperature pH (acidity) folded unfolded “denatured”
This is the longest word in the English language characters which is the name of a protein, but the word is actually the arrangement of the a.a’s that make up the protein! Methionylglutaminylarginyltyrosylglutamylserylleucylphen- ylalanylalanylglutaminylleucyllysylglutamylarginyllysylgluta- mylglysylalanylphenylalanylvalylprolylphenylalanylyalylthre- onylleucylglcycylaspartylprolylglicylisoleucyglutamylgluta- minlserylleucyllysylisoleucylaspartylthreonylleucylisoleu- cylglutamylalanylglyclyalanylaspartylalanylleucyglutamylle- ucylgluycylisoleucylproluylphenylalanyserylaspartyprolylleu- celalanylaspartylglycylprolylthreonylisolleucyglutaminylaspa- raginylalanythreonylleucylarginylalanylphenylalanylalanylal- anylglycylvalylthreonylprolylalanylglutaminylcysteinylphen- ylalanylglglutamylmethionylleucyalanylleucylisoleucylarginyl- glutaminyllysylhistidylprolyuthreonylisoleucylprolylisoleuc- ylglycylleucylleucylmethionyltyrosylalanylasbaraginylleucyl- valylphenylalanylsparaginyyllysylglycylisoleucylaspartylglut- amylphenylalanylyltyrosylalanylglutaminylcysteinylglutamyll- ysylvalylglycylvalylspartylserylvalylleucylvallalanylaspart- ylvalylprolylvalvlglutaminylglutamylserylalanylprolylpheny- lalalrginylglutaminylalanylalanylleucylarginylhistidylasp- araginylvalylalalprolylisoleucylphenylalanylisoleucylcystei- nylprolyprolylaspartylalanylaspartylaspartyspartyleucylle- ucylarginylglutaminylisoleucylalanylseryltyroslglycylargin- ylglycyltyrosylthreonyltyrosylleucylleucylserylarginlalanyl- glycylvalylthreonylglycylalanylglutamylasparaginylarginyla- nylalanylleucylprolylleucylaspaaginylhistidylleucylvalylalan- yllysylleucyllysylglutamyltyrosylasparagimylalanylalanypro- lylprolylleucylglutaminylglycylphenlalanylglycylisoleyucyls- erylalanylprolylaspartylglutaminylvalyllysylalanylalanylisol- eucylalspartylalanylglycylalanylalanylglycylalanylasoleucylse- rylglycylserylalanylisoleucylbalyllysylisoleucylisoleucylgluta- mylglutaminylhistidylasparaginylisoleucylglutamylpronylglu-0 tamyllysylmethionylluecylalanylalanyoeucyllysylvalylpheny- lalanylvalylglutamilylprolylmethionyllysylalanylalanylthreo- nylarginylserine
Proteins insulin collagen (skin) hemoglobin Examples –muscle –fingernails, claws –skin –hair –enzymes example: pepsin –hormones example: insulin
Proteins Function: –many, many functions hormones –insulin movement –muscle immune system –protect against germs enzymes –help chemical reactions
Nucleic acids
Enzymes: “Helper” Protein molecules
Flow of energy through life Life is built on chemical reactions
Chemical reactions of life Processes of life –building molecules synthesis –breaking down molecules digestion ++
Nothing works without enzymes! How important are enzymes? –all chemical reactions in living organisms require enzymes to work building molecules –synthesis enzymes breaking down molecules –digestive enzymes –enzymes speed up reactions ++ enzyme We can ’ t live without enzymes!
Examples synthesis digestion ++ enzyme
Enzymes are proteins Each enzyme is the specific helper to a specific reaction –each enzyme needs to be the right shape for the job –enzymes are named for the reaction they help sucrase breaks down sucrose proteases breakdown proteins lipases breakdown lipids DNA polymerase builds DNA Oh, I get it! They end in -ase
Enzymes aren’t used up Enzymes are not changed by the reaction –used only temporarily –re-used again for the same reaction with other molecules –very little enzyme needed to help in many reactions enzyme substrateproduct active site
It’s shape that matters! Lock & Key model –shape of protein allows enzyme & substrate to fit –specific enzyme for each specific reaction
1 2 3
Enzyme vocabulary Enzyme –helper molecule Catalyst = enzyme Substrate –molecule that enzymes work on Enzyme-substrate complex –enzyme & molecule temporarily joined Active site –part of enzyme that substrate molecule fits into
What affects enzyme action 1. Correct protein structure –correct order of amino acids –why? enzyme has to be right shape
What affects enzyme action? 2. Temperature –why? –enzyme has to be right shape 3. pH (acids & bases) –why? –enzyme has to be right shape
More about Enzymes: What Affects Enzymes
Enzyme concentration Effect on rates of enzyme activity –as increase amount of enzyme = increases how fast the reaction happens more enzymes = more frequently they collide with substrate
Enzyme concentration amount of enzyme reaction rate What’s happening here?!
Substrate concentration Effect on rates of enzyme activity –as increase amount of substrate = increases how fast the reaction happens more substrate = more frequently they collide with enzyme
Substrate concentration amount of substrate reaction rate What’s happening here?!
37° Temperature temperature reaction rate What’s happening here?!
Temperature Effect on rates of enzyme activity –Optimum temperature greatest number of collisions between enzyme & substrate human enzymes = 35°- 40°C (body temp = 37°C) –Raise temperature denature protein = unfold = lose shape –Lower temperature T° molecules move slower decrease collisions
How do cold-blooded creatures digest?
7 pH reaction rate stomach pepsin intestines trypsin What’s happening here?!
pH Effect on rates of enzyme activity –pH changes protein shape –most human enzymes = pH 6-8 depends on where in body pepsin (stomach) = pH 3 trypsin (small intestines) = pH 8
For enzymes… What matters? SHAPE!
Reviews everything about enzymes Active site, lock & key, factors that affect