Biochemistry Functional Groups

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”

Chapter 4 Organic chemistry – the study of carbon compounds Organic compounds have carbon in them (& usually H) – Exception: CO 2 is considered INORGANIC – Range from simple to big molecules

Organic? For a long time, the term organic was strictly associated with the chemistry of life. Until scientists gained the ability to synthesize carbon compounds, the only “factories” making carbon compounds were living organisms, hence the connection to “all natural”.

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 ONC 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 H 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

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

6 functional groups important in chemistry of life 1.Hydroxyl 2.Carbonyl 3.Carboxyl 4.Amino 5.Sulfhydryl 6.Phosphate 7.Methyl (yes…another one)

Functional Groups 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 H 2 0)

Ethanol and Sugar Ethanol: Sugar:

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

Ket o ne Aldehyde – **Think: all the way at the end!

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

Functional Groups cont’d 4. Amino Group (-NH 2 ) 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

Functional Groups cont’d 6. Phosphate Group (-OPO 3 - ) Organic phosphates

Functional Groups cont’d 7. Methyl Group (-CH 3 ) Usually not as reactive as other groups Used in gene expression

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