Topic 2.1
Molecules to Metabolism
Urea & Falsification of Vitalism
Vitalism – theory the origin and phenomena of life are due
to a vital principle, which is different from chemical or
physical forces.

Organic compounds could only be made with the help of a
“vital principle”

1872 Urea synthesized artificially – first organic compound

NO Vital Principle involved

Evidence against theory of vitalism
Scientist accept that processes in living organisms are
governed by same chemical and physical forces as in nonliving matter
Hemoglobin still not able to be synthesized in lab
Urea

Nitrogen-containing compound w/ simple structure

Component of urine

Naturally produced when excess of amino acids in body, to remove nitrogen

Chemical reactions in liver, catalyzed by enzymes produce Urea

Transported to kidneys  urine

Artificially ammonia + carbon dioxide  ammonium carbamate  urea + water

100 million tons produced annually. Nitrogen fertilizer
carbon

15th most abundant element on earth

Forms up to 4 covalent bonds with other atoms, allowing
for complex structures

Forms single, double & triple bonds
C
Carbohydrates
Carbon, hydrogen & oxygen
2 Hydrogen:1 Oxygen
Lipids
Insoluble in water
Steroids, waxes, fatty acids, triglycerides
Triglycerides: fats if solid at room temp, oils if liquid
Proteins
One or more chains of amino acids
All amino acids contain carbon, hydrogen, oxygen & nitrogen
20 amino acids contain sulfer
Nucleic acids
Chains of nucleotides
Nucleotides contain carbon, hydrogen, oxygen, nitrogen and phosphorous
Deoxyribonucleic acid
Ribonucleic acid
Functional groups
Methyl
Group
Carboxyl
Group
Hydroxyl
Group
Aldehyde
Group
Amino
Group
Ketone
Group
Ribose

C5H10O5

5-membered ring with side chain

4 carbon atoms in ring, one in side chain

Carbons numbered starting with number 1 on right

Hydroxyl groups (OH) on carbons 1, 2 & 3 point up, down, and
down respectively
Glucose

C6H12O6

Six-membered ring with side chain

5 carbons in ring, one in side chain

Carbons numbered starting with 1 on right

Hydroxyl group (OH) on carbons 1, 2, 3, 4 point down, down, up and
down

*** glucose in plants making cellulose: hydroxyl points up.
Saturated Fatty Acids

Carbon atoms form an unbranched chain

Saturated acids contain only single bonds

Usually between 14-20 carbon atoms

Carboxyl group at one end of chain

3-hydrogen atoms at other end

All middle carbons bonded to 2 hydrogen atoms
Amino Acids

Carbon in center of molecule,
bonded to 4 different things

An amine group

A carboxyl group

A hydrogen atom

The R group, which is variable
Identifying molecules

Proteins contain C, H, O and N

Many proteins contain sulfur. Carbohydrates and
lipids don’t.

Carbohydrates contain C, H, O, but No N

Carbohydrates contain hydrogen and oxygen in 2:1
ration

Lipids contain less oxygen than carbohydrates
Metabolism

The sum of all enzyme-catalysed reactions in a cell or
organism.

A metabolic pathway is either a chain of events, each
catalysed by an enzyme, or a cycle of reaction.
http://staff.jccc.net/pdecell/metabolism/enzymes/feedback.gif
http://1.bp.blogspot.com/-z5q_jRGpCR4/UZDCDTG6XI/AAAAAAAAANM/JJ1JZ-ub7JU/s1600/krebs-cycle.jpg
Anabolism vs. Catabolism

Synthesis of complex
molecules from simpler ones

Monomers 
macromolecules
(amino acids  protein)

Condensation reactions
where water is produced

Example: ?
http://www.anabolicsmall.com/images/anabolic-steroidalternatives.jpg
• Breakdown of complex
molecules to simpler ones
• Macromolecules 
monomers
(protein  amino acid)
• Hydrolysis reactions where
water is consumed
• Example: ?
http://www.mariowiki.com/images/d/d6/Mariohammer.jpg
examples
Anabolism
Catabolism

Protein synthesis in ribosomes
*Digestion of food

DNA synthesis
*Cell respiraton

Photosynthesis
*Digestion of complex carbon compounds

Synthesis of complex carbohydrates
including starch, cellulose & glycogen
in dead organic matter by decomposers