1. 2.1 – Molecules to Metabolism

2. Essential Idea:
Living organisms control their composition by a complex web of chemical reactions.

3. 2.1
Molecules to Metabolism
Understandings:
Molecular biology explains living processes in terms of the chemical substances involved
Carbon atoms can form four covalent bonds allowing a diversity of stable compounds to exist
Life is based on carbon compounds including carbohydrates, lipids, proteins and nucleic acids
Metabolism is the web of all the enzyme – catalyzed reactions in a cell or organism
Anabolism is the synthesis of complex molecules from simpler molecules including the formation of macromolecules from monomers by condensation reactions
Catabolism is the breakdown of complex molecules into simpler molecules including the hydrolysis of macromolecules into monomers
Application
Use urea as an example compound that is produced by living organisms but can also be artificially synthesized
Skills
Draw molecular diagrams of glucose, ribose, a saturated fatty acid and a generalized amino acid
Identify biochemicals such as sugars, lipids or amino acids from molecular diagrams

4. I. Carbon
A. Uniquely suited to being the foundation of biological molecules 1. Forms four covalent bonds to fill its outer electron shell a. Remember – covalent bonds are strong and stable b. Can be a combination of single, double, and triple bonds

6. II. Organic Molecules
Carbon-based molecules that are the basis of all living organisms
1. Carbon dioxide is the big exception – NOT organic
Fall into 4 major categories
Carbohydrates
Lipids
Proteins
Nucleic Acids
*Also called macromolecules, biomolecules

7. Macromolecule
Elements
Subcomponents/
monomers
Function
Carbohydrates
(aka polysaccharides)
C, H, O
Monosaccharides, disaccharides (aka simple sugars)
Energy source, short-term energy storage
Lipids
Usually glycerol combined with fatty acids (triglycerides)
Long-term energy storage, cell membranes, hormones, insulation
Proteins
(aka polypeptides)
C, H, O, N
Amino Acids
Regulate reactions, transport molecules, membrane channels and pumps, chemical messengers, fight disease
Nucleic Acids (DNA, RNA)
C, H, O, N, P
Nucleotides
Store and transmit genetic information, code for and help build proteins

8. Drawings and identification
1. Monosaccharides are generally rings – look like pentagons or hexagons. Carbons indicated by the corners and numbers clockwise.
Glucose

9. 2. Polysaccharides are generally multiple glucose molecules strung together

10. 3. Saturated Fatty acids – Carboxyl group (-COOH), long hydrocarbon chain, and a methyl (CH3-)

11. 4. Triglyceride – glycerol backbone with three fatty acid chains

12. 5. Amino acid – central carbon surrounded by an amine, a hydrogen, a carboxyl, and an R group (R group is different on each of the 20 amino acids, everything else is the same)

13. III. Metabolism
A. Web of all the enzyme-catalyzed reactions in a cell or organism
B. Describes the totality of chemical processes that occur within a living organisms in order to maintain life.
C. Serves two functions:
1. Provides source of energy for cellular processes (growth, reproduction)
Enables the synthesis and assimilation of new material for use within the cell
D. Made up of catabolism and anabolism

14. 1. Catabolism
a. Breaking down large molecules (polymers) into smaller ones (monomers)
b. Relies on hydrolysis reactions – use water molecules to break apart
c. Releases energy when bonds are broken (exergonic)

16. Poly/disaccharides to monosaccharides

18. Triglyceride into glycerol and fatty acids

20. Protein to amino acids

21. 2. Anabolism
a. Building large molecules (polymers) by joining smaller molecules (monomers) together
b. Relies on condensation reactions – removal of water (also called dehydration reactions)
c. Uses energy to form bonds
(endergonic)

23. Monosaccharides to Di/Polysaccharides

24. Glycerol and fatty acids to Triglycerides

26. Amino Acids to Polypeptides

27. V. Artificial Synthesis of Urea
Vitalism was a doctrine that dictated that organic molecules could only be synthesized by living systems. It was believed that living things possessed a certain “vital force” needed to make organic molecules. Organic compounds were thought to possess a non-physical element lacking from inorganic molecules.
Vitalism was disproven with the discovery that organic molecules can be artificially synthesized , Frederick Woehler heated an inorganic salt (ammonium cyanate) and produced urea. Urea is a waste product of nitrogen metabolism and is eliminated by the kidneys in mammals. The artificial synthesis of urea demonstrates that organic molecules are not fundamentally different to inorganic molecules.