Chapter 4 Functional Groups Chapter 5 Macromolecules Biochemistry Chapter 4 Functional Groups Chapter 5 Macromolecules

Carbon—The Backbone of Biological Molecules All living organisms Are made up of chemicals based mostly on carbon due to its bonding ability All life considered “carbon based life-forms”

Biochemistry Part 1 Chapter 4: Functional Groups

Chapter 4 Organic chemistry the study of carbon compounds Organic compounds have carbon in them (& usually H) Exception: CO2 is considered INORGANIC Range from simple to big molecules

Formation of Bonds w/ Carbon Carbon atoms forms diverse molecules b/c carbon has 4 valence electrons bind to to 4 other atoms can form 4 covalent bonds with itself or other atoms  very important in living things! Carbon has bonding versatility allows it to form many diverse molecules, including carbon skeletons (carbon “chains”)

The electron configuration of carbon Gives it covalent compatibility with many different elements H O N C Hydrogen (valence = 1) Oxygen (valence = 2) Nitrogen (valence = 3) Carbon (valence = 4) Figure 4.4

Molecular Diversity Arising from Carbon Skeleton Variation Carbon chains Form skeletons of most organic molecules Vary in length and shape Straight Branched Rings

Hydrocarbons Organic molecules consisting of only C and Ex: petroleum; lipid ‘tails’ Found in many of cell’s organic molecules Ex: fat molecules Covalent bonding btw C-H nonpolar (hydrophoic) High energy storage

Example of a Hydrocarbon (a) A fat molecule (b) Mammalian adipose cells 100 µm Fat droplets (stained red) Figure 4.6 A, B

ISOMERS Isomers same molecular formula, but different structure & properties Have same # of atoms arranged differently 3 types of isomers structural~ differ in covalent bonding arrangement geometric~ differ in spatial arrangement Arise from inflexibility of double C bond cis (same side) vs. trans (opposite sides) enantiomers~ mirror images of each other Ex: used in pharmacological industry

1 usually active; other inactive Example of Isomers Straight vs. branched Cis vs. trans 1 usually active; other inactive Asymmetrical Carbon

Enantiomers Are important in the pharmaceutical industry L-Dopa (effective against Parkinson’s disease) D-Dopa (biologically inactive) Figure 4.8

Functional Groups Functional groups parts of organic molecules involved in chemical rxns (i.e.-chemically reactive groups) each functional group behaves in a consistent fashion from 1 organic molecule to the next # & arrangement of groups helps give molecules unique, distinctive chemical properties

7 functional groups important in chemistry of life Hydroxyl Carbonyl Carboxyl Amino Sulfhydryl Phosphate Methyl

Functional Groups 1. Hydroxyl Group (-OH) H bonded to O Attachments replace 1+ of H’s bonded to C skeleton of the hydrocarbon Each GROUP are HYDROPHILIC  increase organic molecule solubility in water 1. Hydroxyl Group (-OH) H bonded to O Make alcohols, sugars polar (b/c of oxygen electronegivity) soluble in water (attracts H20)

Functional Groups 2. Carbonyl Group (C=O) C double bond to O Aldehyde (at the end of C skeleton) Ketone (INSIDE Carbon skeleton) Ex: Acetone, Propanal

Aldehyde **Think: all the way at the end! Ketone

Functional Groups cont’d 3. Carboxyl Group (-COOH) O double bonded to C to hydroxyl Carboxylic acids (organic acids) Covalent bond between O and H Polar Dissociation  H ion source (Acidic properties) **Think: Carboxyl has a hydroxyl!

Functional Groups cont’d 4. Amino Group (-NH2) N to 2 H atoms Makes Amines Acts as a base (+1) Also makes AMINO ACIDS Have both amino and carboxyl groups

Functional Groups cont’d 5. Sulfhydral Group (-SH) sulfur bonded to H Makes disulfide bridges 2 sulfhydral groups can interact to stabilize protein structure

Functional Groups cont’d 6. Phosphate Group (-OPO3-) Organic phosphates Forms phosphate ion Covalently attached by 1 of its O to the C skeleton Can transfer energy btw organic molecules Ex: ATP

Functional Groups cont’d 7. Methyl Group (-CH3) Usually not as reactive as other groups Used in gene expression

Male or Female!! Only one little itty bitty difference that separates the sexes