biochemistry
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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
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