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

Why do we eat?  We eat to take in more of these chemicals  Food for building materials  to make more of us (cells)  for growth  for repair  Food to make energy  calories  to make ATP ATP

What do we need to eat?  Foods to give you more building blocks & more energy  for building & running bodies  carbohydrates  proteins  fats  nucleic acids  vitamins  minerals, salts  water

 Water  65% of your body is H 2 O  water is inorganic  doesn’t contain carbon  Rest of you is made of carbon molecules  organic molecules  carbohydrates  proteins  fats  nucleic acids Don’t forget water

How do we make these molecules? We build them!

Building large molecules of life  Chain together smaller molecules  building block molecules = monomers  Big molecules built from little molecules  polymers

 Small molecules = building blocks  Bond them together = polymers Building large organic molecules

Building important polymers sugar – sugar – sugar – sugar – sugar – sugar nucleotide – nucleotide – nucleotide – nucleotide Carbohydrates = built from sugars Proteins = built from amino acids Nucleic acids (DNA) = built from nucleotides amino acid amino acid – amino acid – amino acid – amino acid – amino acid –

How to build large molecules  Synthesis (dehydration- synthesis)-take water out to make something larger  building bigger molecules from smaller molecules  building cells & bodies  repair  growth  reproduction + ATP

How to take large molecules apart  Digestion-  taking big molecules apart (hydrolysis) adding water to break molecules apart  getting raw materials  for synthesis & growth  making energy (ATP)  for synthesis, growth & everyday functions + ATP

Example of digestion starchglucose ATP  Starch is digested to glucose

Example of synthesis amino acidsprotein amino acids = building block protein = polymer  Proteins are synthesized by bonding amino acids

Penguins gone bad! Any Questions?

Old Food Pyramid

New Food Pyramid

Carbohydrates

Carbohydrates: OH H H HO CH 2 OH H H H OH O Energy molecules

Carbohydrates  Building block molecules = sugar sugar - sugar - sugar - sugar - sugar sugars

sucrose Carbohydrates  Function:  quick energy  energy storage  structure  cell wall in plants  Examples  sugars  starches  cellulose (cell wall) glucose C 6 H 12 O 6 starch

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

Building carbohydrates  Synthesis | glucose | glucose 1 sugar = monosaccharide 2 sugars = disaccharide | maltose mono = one saccharide = sugar di = two

Building carbohydrates  Synthesis | fructose | glucose 1 sugar = monosaccharide | sucrose (table sugar) 2 sugars = disaccharide How sweet it is!

BIG carbohydrates-polysaccharides  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 poly = many

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 well  most carnivores cannot digest cellulose  that’s why they eat meat to get their energy & nutrients  cellulose = roughage  stays undigested  keeps material moving in your intestines

Different Diets of Herbivores 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 so well?  BACTERIA live in their stomachs & help digest cellulose-rich (grass) meals Eeeew… Chewing cud?

Let’s build some Carbohydrates! EAT X

Activities  building starch by bonding together paper glucose molecules  eat carrots, celery, cookies

Proteins

Proteins: Multipurpose molecules

collagen (skin) Proteins insulin Examples  muscle  skin, hair, fingernails, claws  collagen, keratin  pepsin  digestive enzyme in stomach  insulin  hormone that controls blood sugar levels pepsin

Proteins  Function:  many, many functions  hormones  signals from one body system to another  insulin  movement  muscle  immune system  protect against germs  enzymes  help chemical reactions

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 There’s 20 of us… like 20 different letters in an alphabet! Can make lots of different words

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 amino acid

Water-fearing amino acids  Hydrophobic  “water fearing” amino acids  try to get away from water in cell  the protein folds

Water-loving amino acids  Hydrophillic  “water loving” amino acids  try to stay in water in cell  the protein folds

pepsin For proteins: SHAPE matters! collagen  Proteins fold & twist into 3-D shape  that’s what happens in the cell!  Different shapes = different jobs hemoglobin growth hormone

It’s 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” In Biology, it’s not the size, it’s the SHAPE that matters!

Let’s EAT some Proteins!

Activities  demo raw egg vs. cooked egg  drop raw egg into boiling water, like egg drop soup  compare raw egg to hard-boiled egg  demo cheese-making with heated milk & vinegar  make yogurt

Lipids: Fats & Oils

Lipids Concentrated energy molecules

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!

Structure of Fat not a chain (polymer) = just a “big fat molecule”

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

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

Let’s build some Lipids!

Enzymes: “Helper” Protein molecules s1

Flow of energy through life  Life is built on chemical reactions s2

Chemical reactions of life  Processes of life  building molecules  synthesis  breaking down molecules  digestion ++ s3

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! s4

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 s6

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  Substrate  molecule that enzymes work on  Enzyme-substrate complex  enzyme & molecule temporarily joined  Active site  part of enzyme that substrate molecule fits into s10

What affects enzyme action  Correct protein structure  correct order of amino acids  why? enzyme has to be right shape  Temperature  why? enzyme has to be right shape  pH (acids & bases)  why? enzyme has to be right shape

More about Enzymes: What Affects Enzymes

What affects how well an enzyme works?  Correct protein structure  correct order of amino acids  why? enzyme has to be right shape  Temperature  why? enzyme has to be right shape  pH  why? enzyme has to be right shape

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?! s17

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 s19

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 s21

For enzymes… What matters? SHAPE!