The Nature of LifeThe Nature of Life

Section 2-4:Section 2-4:

The Chemistry of Living The Chemistry of Living ThingsThings

Elements vs. CompoundsElements vs. Compounds

ElementElement – a pure substance that – a pure substance that cannot be broken down into any cannot be broken down into any simpler substances by ordinary means simpler substances by ordinary means Examples: Helium, Copper, Zinc, Sulfur, Examples: Helium, Copper, Zinc, Sulfur,

Lead, etc. (everything on the Periodic Lead, etc. (everything on the Periodic Table)Table)

CompoundCompound – two or more different – two or more different elements chemically joined (water, elements chemically joined (water, sugar, salt, carbon dioxide, rust, etc.)sugar, salt, carbon dioxide, rust, etc.)

Elements vs. CompoundsElements vs. Compounds

The properties of compounds are The properties of compounds are often totally different from those of often totally different from those of the elements that make them upthe elements that make them up

For Example – CFor Example – C66HH1212OO66 is a molecule is a molecule of sugar (glucose). It is nothing like of sugar (glucose). It is nothing like pure carbon (carbon rods or pure carbon (carbon rods or diamonds), pure hydrogen (an diamonds), pure hydrogen (an explosive gas) or oxygen (another explosive gas) or oxygen (another gas)gas)

Inorganic CompoundsInorganic Compounds

Compounds that do Compounds that do not contain carbon not contain carbon

The exception is The exception is carbon dioxide carbon dioxide (CO(CO22) which is ) which is considered considered inorganicinorganic

Examples include:Examples include: Ammonia (NHAmmonia (NH33)) Salt (NaCl)Salt (NaCl) Water (HWater (H22O)O) Steel/rustSteel/rust GlassGlass MetallicsMetallics Minerals Minerals Plant Fertilizer Plant Fertilizer

(N,P,K)(N,P,K)

Organic CompoundsOrganic Compounds Compounds containing carbonCompounds containing carbon

Those basic to life include:Those basic to life include:CarbohydratesCarbohydratesLipids (fats and oils)Lipids (fats and oils)ProteinsProteinsNucleic AcidsNucleic Acids

CarbohydratesCarbohydrates

Composed of carbon, hydrogen and Composed of carbon, hydrogen and oxygenoxygen

Includes sugars, starches, and Includes sugars, starches, and cellulosecellulose

The product of photosynthesis; all The product of photosynthesis; all carbohydrates originate from carbohydrates originate from photosynthesis whose end product is photosynthesis whose end product is the simple sugar glucosethe simple sugar glucose

CarbohydratesCarbohydrates

Glucose molecules can be joined Glucose molecules can be joined together to form:together to form: starch molecules - plants store energy in starch molecules - plants store energy in

the form of starchthe form of starch Cellulose molecules – the primary Cellulose molecules – the primary

construction material of plantsconstruction material of plants Glucose can also be broken down Glucose can also be broken down

during respiration to release energy during respiration to release energy to fuel other cellular processesto fuel other cellular processes

Carbohydrates - GlucoseCarbohydrates - Glucose

Carbohydrates - StarchCarbohydrates - Starch

Carbohydrate - CelluloseCarbohydrate - Cellulose

Lipids: Fats and OilsLipids: Fats and Oils

Composed of carbon, hydrogen and Composed of carbon, hydrogen and oxygen (the same as carbohydrates)oxygen (the same as carbohydrates)

Essential to life because they are Essential to life because they are part of all cell membranespart of all cell membranes

Used to store energy in animalsUsed to store energy in animals At room temperature fats are solid At room temperature fats are solid

while oils are liquidwhile oils are liquid

LipidsLipids

ProteinsProteins Composed of carbon, hydrogen, oxygen Composed of carbon, hydrogen, oxygen

and and nitrogen nitrogen and sometimes sulfur and sometimes sulfur All made of the same 20 building blocks All made of the same 20 building blocks

called amino acidscalled amino acids Humans have an estimated 30,000 Humans have an estimated 30,000

different proteinsdifferent proteins Each protein has a unique number and Each protein has a unique number and

sequence of amino acids; a change in one sequence of amino acids; a change in one amino acid creates a different protein that amino acid creates a different protein that may not function may not function

ProteinsProteins

An essential part of all living cellsAn essential part of all living cells Proteins are part of all cell membranes, Proteins are part of all cell membranes,

regulating transport of substances through regulating transport of substances through the membranethe membrane

As enzymes proteins regulate all metabolic As enzymes proteins regulate all metabolic activities of cells activities of cells

Enzymes act as catalysts – substances Enzymes act as catalysts – substances that speed up or slow down chemical that speed up or slow down chemical reactions without being changed reactions without being changed themselves.themselves.

Proteins in Animals Proteins in Animals

Make up 50% of the body’s dry matterMake up 50% of the body’s dry matter Collagen (in skin, bones, tendons, and Collagen (in skin, bones, tendons, and

cartilage) muscle fibers, hair, and cartilage) muscle fibers, hair, and nails, are all proteinnails, are all protein

Protein is a vital part of blood Protein is a vital part of blood (hemoglobin)(hemoglobin)

Antibodies of the immune system are Antibodies of the immune system are proteinprotein

ProteinProtein

Nucleic AcidsNucleic Acids

Composed of carbon, hydrogen, Composed of carbon, hydrogen, oxygen and nitrogenoxygen and nitrogen

The “Blueprints” of lifeThe “Blueprints” of life Very large molecules/compounds Very large molecules/compounds

that store information that helps the that store information that helps the body make the proteins it needsbody make the proteins it needs

Controls the assembly of amino acids Controls the assembly of amino acids into proteinsinto proteins

Nucleic AcidsNucleic Acids

DNA – Deoxyribonucleic acidDNA – Deoxyribonucleic acidStores the information/codeStores the information/codeTransmits it from parent to Transmits it from parent to offspringoffspring

RNA – Ribonucleic acidRNA – Ribonucleic acidTranslates the message of DNA Translates the message of DNA into proteinsinto proteins

DNADNA

The EndThe End