1 Carbon The LEGO of biological molecules! Copyright Cmassengale.

1

CarbonThe LEGO of

biological molecules!

Copyright Cmassengale

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Carbon-based MoleculesAlthough a cell is mostly water, the rest of the cell consists mostly of carbon-based molecules

Organic chemistry is the study of carbon compounds


Organic molecules are complex molecules of life, built on a framework of carbon atoms

•Carbohydrates

•Lipids

•Proteins

•Nucleic Acids

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Carbon is a Versatile Atom

It has four electrons in an outer shell that holds eight

Carbon can share its electrons with other atoms to form up to four covalent bonds


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Hydrocarbons

The simplest carbon compounds …

Contain only carbon & hydrogen atoms


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Uses of Organic MoleculesA typical cell in

your body has about 2 meters of DNA

A typical cow produces over 200 pounds of methane gas each year


Isomers

Isomers are compounds with the same molecular formula but different structures and properties:Structural isomers have different covalent arrangements

of their atomsGeometric isomers have the same covalent

arrangements but differ in spatial arrangementsEnantiomers are isomers that are mirror images of each

other

Animation: IsomersAnimation: Isomers

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

http://www.biologyjunction.com/04_07Isomers_A.html

Fig. 4-7

Pentane

(a) Structural isomers

(b) Geometric isomers

2-methyl butane

cis isomer: The two Xs areon the same side.

trans isomer: The two Xs areon opposite sides.

(c) Enantiomers

L isomer D isomer

Enantiomers are important in the pharmaceutical industry

Two enantiomers of a drug may have different effects

Differing effects of enantiomers demonstrate that organisms are sensitive to even subtle variations in molecules

Animation: L-DopaAnimation: L-Dopa

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

http://www.biologyjunction.com/04_07L_Dopa_A.html

Fig. 4-8

Drug

Ibuprofen

Albuterol

Condition

Pain;inflammation

Asthma

EffectiveEnantiomer

S-Ibuprofen

R-Albuterol

R-Ibuprofen

S-Albuterol

IneffectiveEnantiomer

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Carbon can use its bonds to::

Attach to other carbons

Form an endless diversity of carbon skeletons


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Large Hydrocarbons:

Are the main molecules in the gasoline we burn in our cars

The hydrocarbons of

fat molecules provide energy for our bodies


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Shape of Organic Molecules

Each type of organic molecule has a unique three-

dimensional shape

The shape determines its function in an

organism


Space-filling models show howAtoms sharing electrons overlap

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Functional Groups are:Groups of atoms that give

properties( such as polarity, acidity) to the compounds to which they attach

Gained Electrons Lost ElectronsCopyright Cmassengale

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Common Functional Groups


Effects of Functional Groups: Sex Hormones

What cells Do to Organic Compounds•Metabolism

–Activities by which cells acquire and use energy to construct, rearrange, and split organic molecules

–Allows cells to live, grow, and reproduce

–Requires enzymes (proteins that increase the speed of reactions)

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What cells Do to Organic CompoundsLarge molecules are called polymersPolymers are built from smaller molecules called monomers

Biologists call them macromolecules


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Examples of Polymers

Proteins

Lipids

Carbohydrates

Nucleic Acids


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Most Macromolecules are Polymers

Polymers are made by stringing together many smaller molecules called monomers

Nucleic Acid

Monomer


Structural model: each line is a covalentbond; two lines are double bonds;three lines are triple bonds.

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Linking Monomers

Cells link monomers by a process

called condensation or dehydration synthesis (removing a molecule of

water)

This process joins two sugar monomers to make a double

sugar

Remove H

Remove OH

H2O Forms


http://nhscience.lonestar.edu/biol/dehydrat/dehydrat.html

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Breaking Down PolymersCells break

down macromolecules by a process called hydrolysis (adding a molecule of water)

Water added to split a double sugar


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Macromolecules in Organisms

There are four categories of large molecules in cells:

Carbohydrates

Lipids

Proteins

Nucleic Acids


Structure Dictates Function

•We define cells partly by their capacity to build complex carbohydrates, lipids, proteins, and nucleic acids

•All of these organic compounds have functional groups attached to a backbone of carbon atoms.

•Most biological molecules have at least on functional group ( a cluster of atoms that imparts specific chemical properties to a molecule)

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End


1 Carbon The LEGO of biological molecules! Copyright Cmassengale.

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