The Chemistry of Life What are living creatures made of? Why do we have to eat? 2006-2007

Organic and inorganic compounds There are two types of compounds that are important to living things: Organic and inorganic compounds Organic compounds contain the elements carbon AND hydrogen. There are 4 types of organic compounds that are important to living things.

Some examples include: water (formula: H2O) salt (formula: NaCl) Inorganic compounds are also important to living things. They DO NOT contain BOTH carbon and hydrogen. Some examples include: water (formula: H2O) salt (formula: NaCl) Simple Chemistry Clip

ORGANIC vs. INORGANIC Carbon based molecules are called organic molecules. Non-carbon based molecules—water, oxygen, and ammonia are inorganic molecules.

Molecules of Life Put C, H, N, O, P, S together in different ways to build living organisms What are bodies made of? carbohydrates sugars & starches proteins fats (lipids) nucleic acids DNA, RNA

ATP 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

Don’t forget water Water Rest of you is made of carbon molecules 65% of your body is H2O water is inorganic doesn’t contain carbon Rest of you is made of carbon molecules organic molecules carbohydrates proteins fats nucleic acids

The Role of Carbon in Organisms Organic compounds contain carbon A carbon atom has four electrons available for bonding in its outer energy level. In order to become stable, a carbon atom forms four covalent bonds that fill its outer energy level. Carbon compounds vary greatly in size. When carbon atoms bond to each other, they can form straight chains, branched chains, or rings.

Types of carbon backbones: - straight chain - branched chain - can form double bonds - can form ring structures

CARBON SKELETONS

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

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

Making and Breaking of POLYMERS Cells link monomers to form polymers by dehydration synthesis (building up) Short polymer Unlinked monomer Removal of water molecule Longer polymer

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

How to build large molecules Dehydration Synthesis building bigger molecules from smaller molecules building cells & bodies repair growth reproduction + ATP

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

How to take large molecules apart Hydrolysis (Digestion) taking big molecules apart getting raw materials for synthesis & growth making energy (ATP) for synthesis, growth & everyday functions + ATP

Making and Breaking of POLYMERS Polymers are broken down to monomers by the reverse process, hydrolysis (hydro ~ add water; lysis ~ to split) Addition of water molecule

Example of digestion starch glucose Starch is digested to glucose ATP

1. CARBOHYDRATES composed of carbon, hydrogen, and oxygen with a ratio of about two hydrogen atoms and one oxygen atom for every carbon atom.

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

Carbohydrates Function: Examples glucose C6H12O6 sucrose starch quick energy energy storage structure cell wall in plants Examples sugars starches cellulose (cell wall) glucose C6H12O6 sucrose starch

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

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

BIG carbohydrates Polysaccharides large carbohydrates starch glycogen 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… = polysaccharide starch (plant) energy storage glycogen (animal)

Digesting starch vs. cellulose enzyme starch easy to digest Animals do not have the enzyme to digest cellulose. We need the help of bacteria living in our intestines. enzyme cellulose hard to digest

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 Cross-linking between polysaccharide chains = rigid & hard to digest The digestion of cellulose governs the life strategy of herbivores. Either you do it really well and you’re a cow or an elephant or a horse (spend a long time digesting a lot of food with a little help from some microbes & have to walk around slowly for a long time carrying a lot of food in your stomach) Or you do it inefficiently and have to supplement your diet with simple sugars, like fruit and nectar, and you’re a gorilla.

Releases energy for cells Organic Compound Composed of: Examples Function Carbohydrate C, H, O Sugar Starch cellulose Releases energy for cells

Lipids (ie. fats, oils, waxes) composed largely of carbon, hydrogen, oxygen They are not true polymers They are grouped together because they do not mix with water (Nonpolar) (ie. fats, oils, waxes)

Lipids Examples fats oils waxes Steroid hormones sex hormones testosterone (male) estrogen (female)

Lipids Function: energy storage cell membrane cushions organs 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 Limit the amount in your diet solid at room temperature Limit the amount in your diet contributes to heart disease deposits in arteries 2003-2004

Lipids include fats, Fats are lipids whose main function is long term energy storage Other functions: Insulation in higher vertebrates “shock absorber” for internal organs Fatty acid Fatty acid 38

Saturated & Unsaturated fats fatty acids of unsaturated fats (plant oils) contain double bonds These prevent them from solidifying at room temperature Saturated fats (lard) lack double bonds They are solid at room temperature

Saturated fats Most animal fats Limit the amount in your diet solid at room temperature Limit the amount in your diet contributes to heart disease deposits in arteries 2003-2004 40

Unsaturated fats Plant, vegetable & fish fats liquid at room temperature the fat molecules don’t stack tightly together Better choice in your diet 2003-2004

Saturated vs. unsaturated 

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 2003-2004

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 2003-2004

Stores and releases MORE energy for cells Organic Compound Composed of: Examples Function Lipid C, H, O Fats Oils Waxes Stores and releases MORE energy for cells Cell membranes are made of lipids