Molecules to Metabolism 2.1

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

CARBON!!!!!!!!! Uniquely suited to being the foundation of biological molecules -Forms four covalent bonds to fill its outer electron shell - Remember – covalent bonds are strong and stable -Can be a combination of single, double, and triple bonds

Carbon based molecules that are the basis of all biological organisms Organic Molecules Carbon based molecules that are the basis of all biological organisms (Big exception = carbon dioxide – not organic) Fall into one of four categories Carbohydrates Lipids Proteins Nucleic Acids (Also called macromolecules, biomolecules, polymers)

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 Long-term energy storage, cell membranes, hormones Proteins (aka polypeptides) C, H, O, N Amino Acids Regulate reactions, transport molecules, membrane channels and pumps, chemical messengers, fight disease Nucleic Acids C, H, O, N, P Nucleotides Store and transmit genetic information, code for and help build proteins

Carbohydrates

Lipids

Proteins

Nucleic Acids

Metabolism Web of all the enzyme-catalyzed reactions in a cell or organism Describes the totality of chemical processes that occur within a living organisms in order to maintain life. Serves two functions: Provides source of energy for cellular processes (growth, reproduction) Enables the synthesis and assimilation of new material for use within the cell What does assimilation mean?

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

Poly/disaccharides to monosaccharides

Triglyceride into glycerol and fatty acids

Protein to amino acids

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

Monosaccharides to Di/Polysaccharides

Glycerol and fatty acids to Triglycerides

Amino Acids to Polypeptides

Nucleotides to Nucleic Acids

Vitalism 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 as a theory has since been disproven with the discovery that organic molecules can be artificially synthesized. 1828, 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.