Pre-AP Biology Carbon Properties

Organic Chemistry Branch of science dealing with the element carbon and its many properties. It is usually associated with all living organisms. About 30% of an organism’s dry weight (called Biomass) is Carbon in organic molecules. Helps to make the organic molecules: Carbohydrates, Lipids, Proteins, and Nucleic Acids. The original source for Carbon in all life forms is Carbon Dioxide. (CO2 in Photosynthesis) Inorganic refers to most compounds not containing Carbon. (CH4 (Methane gas) and CO2 or CO are exceptions. They contain Carbon but are classified as inorganic.)

Carbon Cycle Higher-level consumers Primary consumers Carbon compounds CO2 in atmosphere Photosynthesis Cellular respiration Burning of fossil fuels and wood Higher-level consumers Primary consumers Carbon compounds in water Detritus Decomposition

Carbon’s e- configuration Carbon has versatility in four directions because of the four unpaired electrons in its outer shell. These four unpaired electrons allow carbon to act like an intersection in the building of an organic molecule by using those to form covalent bonds with other atoms. This allows cells to build an almost infinite number of different molecules. Covalent bonding capabilities of Carbon Single Bond between Carbon atoms.(shown as: C-C) Double Bond between Carbon atoms. (shown as: C=C) Triple Bond between Carbon atoms. (shown as: C=C)

Carbon Bonding and Hydrocarbons Molecular Formula Structural Formula Methane Ethane Ethene (ethylene)

Hydrocarbons Molecules containing mostly Carbon and Hydrogen. Most hydrocarbons are energy sources. (Some examples are: Fossil fuels, oils, and fats) The more Hydrogen atoms in a molecule; the more energy there is in the molecule. Hydrocarbons are important parts of cell membranes. (The tails of phospholipids) All hydrocarbons are extremely hydrophobic because they are nonpolar molecules. (“Afraid of” water’s polarity.) Hydrocarbon tails See all the energy in this fat molecule?

Hydrocarbon Tails of a Phospholipid Choline Hydrophilic head Phosphate Glycerol Hydrophobic tails Fatty acids Hydrophilic head Hydrophobic tails Structural formula Space-filling model Phospholipid symbol

Cell Membranes Remember These?

Functional Groups associated with Organic Molecules These are the sites of most organic molecules chemical reactions or properties. (They have a function to do.) Hydroxyls (-OH) This group allows molecules to act as an alcohol or polar molecule. Name usually ends with “ol”. Carbonyls only have one double bonded oxygen. (It takes one stroke to make a lower case “n”.) Aldehydes A is at one end of the alphabet.(Carbonyl is located on the end of the molecule.) Ketones K is in the middle of the alphabet.(Carbonyl is located in the middle of the molecule.) Carboxyl Has two oxygens…one double bonded and one single bonded. (It takes two strokes to make an “x”) These molecules can act as an acid by losing a Hydrogen atom and can also possibly be polar too.

Functional groups serve important purposes in molecules Estradiol Female lion Testosterone Male lion

FUNCTIONAL PROPERTIES LE 4-10aa STRUCTURE (may be written HO—) Ethanol, the alcohol present in alcoholic beverages NAME OF COMPOUNDS FUNCTIONAL PROPERTIES Alcohols (their specific names usually end in -ol) Is polar as a result of the electronegative oxygen atom drawing electrons toward itself. Attracts water molecules, helping dissolve organic compounds such as sugars (see Figure 5.3).

STRUCTURE EXAMPLE NAME OF COMPOUNDS LE 4-10ab Acetone, the simplest ketone STRUCTURE EXAMPLE Acetone, the simplest ketone Propanal, an aldehyde NAME OF COMPOUNDS Ketones if the carbonyl group is within a carbon skeleton FUNCTIONAL PROPERTIES Aldehydes if the carbonyl group is at the end of the carbon skeleton A ketone and an aldehyde may be structural isomers with different properties, as is the case for acetone and propanal.

LE 4-10ac STRUCTURE EXAMPLE Acetic acid, which gives vinegar its sour taste NAME OF COMPOUNDS FUNCTIONAL PROPERTIES Carboxylic acids, or organic acids Has acidic properties because it is a source of hydrogen ions. The covalent bond between oxygen and hydrogen is so polar that hydrogen ions (H+) tend to dissociate reversibly; for example, Acetic acid Acetate ion In cells, found in the ionic form, which is called a carboxylate group.

Amine Contain Nitrogen Can act as bases by picking up free H+. Sulfhydrls Contain Sulfur Sulfur can make Di-Sulfide bridges for “pockets” in protein formation. Phosphate Contain Phosphorus These molecules are usually involved in E Transfers, such as associated with ATP. They can also act like an Anion, a negative ion.  

LE 4-10ba STRUCTURE EXAMPLE Glycine Because it also has a carboxyl group, glycine is both an amine and a carboxylic acid; compounds with both groups are called amino acids. NAME OF COMPOUNDS FUNCTIONAL PROPERTIES Amine Acts as a base; can pick up a proton from the surrounding solution: (nonionized) (ionized) Ionized, with a charge of 1+, under cellular conditions

STRUCTURE EXAMPLE NAME OF COMPOUNDS LE 4-10bb STRUCTURE EXAMPLE (may be written HS—) Ethanethiol NAME OF COMPOUNDS FUNCTIONAL PROPERTIES Thiols Two sulfhydryl groups can interact to help stabilize protein structure (see Figure 5.20).

STRUCTURE EXAMPLE NAME OF COMPOUNDS LE 4-10bc STRUCTURE EXAMPLE Glycerol phosphate NAME OF COMPOUNDS FUNCTIONAL PROPERTIES Organic phosphates Makes the molecule of which it is a part an anion (negatively charged ion). Can transfer energy between organic molecules.