Topic 2: Molecular Biology

2.1 Molecules to metabolism

Learning objectives• U: Molecular biology explains living processes in terms of the chemical

substances involved.• U: Carbon atoms can form four covalent bonds allowing a diversity of stable

compounds to exist.• U: Life is based on carbon compounds including carbohydrates, lipids, proteins

and nucleic acids.• U: Metabolism is the web of all the enzyme-catalysed reactions in a cell or

organism.• U: Anabolism is the synthesis of complex molecules from simpler molecules

including the formation of macromolecules from monomers by condensation reactions.

• U: Catabolism is the breakdown of complex molecules into simpler molecules including the hydrolysis of macromolecules into monomers. 

• A: Urea as an example of a compound that is produced by living organisms but can also be artificially synthesized.

• A: (Skill) Drawing molecular diagrams of glucose, ribose, a saturated fatty acid and a generalized amino acid.

• A: (Skill) Identification of biochemicals such as sugars, lipids or amino acids from molecular diagrams.

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.

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http://staff.jccc.net/pdecell/metabolism/enzymes/feedback.gif

Anabolic vs. Catabolic• Synthesis of complex

molecules from simpler ones• Monomers

macromolecules (amino acids protein)• Condensation reactions

where water is produced• Example: ?

• Breakdown of complex molecules to simpler ones

• Macromolecules monomers

(protein amino acid)• Hydrolysis reactions where

water is consumed• Example: ?

http://www.anabolicsmall.com/images/anabolic-steroid-alternatives.jpg

http://www.mariowiki.com/images/d/d6/Mariohammer.jpg

What does ‘organic’ mean?• In Biology, organic means containing the

element carbon– Exception: carbon dioxide (CO2)

• Carbon is able to form 4 covalent bonds which allows it to form stable compounds.

Carbon containing compounds: building blocks of life

CarbohydratesLipids

Protein Nucleic acids

The most frequently occurring elements in living things are carbon, hydrogen, oxygen and nitrogen

Functional groups you need to know

• Hydroxyl• Ester• Carboxylic acid• Amino• Carbonyl

Skill: Drawing molecular diagrams of alpha-D glucose and beta-D glucose

Skill: Drawing molecular diagram of D-ribose

Skill: Drawing molecular diagram of a saturated fatty acid

http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/Bio%20101/Bio%20101%20Lectures/Biochemistry/saturated%20and%20unsaturated%20fatty%20acids.gif

Skill: Drawing molecular diagram of a saturated fatty acid

H3C – (CH2)n – C OH

O=-

Skill: Drawing molecular diagram of an amino acid

Identify the following as: carbohydrates, lipids, or amino acids

Identify the following as: carbohydrates, lipids, or amino acids

Nature of Science

1) What is the theory of vitalism?2) Why did the successful synthesis of urea in

the laboratory disprove the theory of vitalism?

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