Biochemistry

Chapter 4 Functional

GroupsChapter 5

Macromolecules

Carbon—The Backbone of Biological Molecules

All living organismsAre made up of chemicals based mostly on

carbon due to its bonding abilityAll life considered “carbon based life-forms”

BiochemistryPart 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

Stanley Miller’s Experiment

• The concept of vitalism– idea that organic compounds arise

only within living organisms• disproved when chemists synthesized carbon compounds in lab

»Ex: Miller

–Thoughts shifted from vitalism to mechanism• the view that all natural phenomena are governed by physical and chemical laws.

GasesCH4, NH3, H2O, H2

Stanley Miller’s

Experiment

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 chainsForm skeletons of most organic molecules

Vary in length and shape

StraightBranchedRings

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

ISOMERSIsomers

same molecular formula, but different structure & properties

Have same # of atoms arranged differently

3 types of isomers1.structural~ differ in covalent

bonding arrangement2.geometric~ differ in spatial

arrangement Arise from inflexibility of double C bond cis (same side) vs. trans (opposite sides)

3.enantiomers~ mirror images of each other • Ex: used in pharmacological industry

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

6 functional groups important in chemistry of life

1.Hydroxyl2.Carbonyl3.Carboxyl4.Amino5.Sulfhydryl6.Phosphate7.Methyl (yes…another one)

Functional GroupsAttachments replace 1+ of H’s bonded

to C skeleton of the hydrocarbonEach 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 Groups2. Carbonyl Group (C=O)

–C double bond to O–Aldehyde (at the end of C skeleton)–Ketone (INSIDE Carbon skeleton)–Ex: Acetone, Propanal

• Ketone

• Aldehyde– **Think: all the way

at the end!

Functional Groups cont’d3. 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’d4. 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’d6. 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’d7. 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