Carbon Compounds

Carbon Compounds Organic Biochemistry

Macromolecules 10 minutes maximum for the reading quiz

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Carbon Biochemistry: The molecules of Life

The Tree of Life

What is an organic molecule? Compounds containing carbon • Most carbon containing compounds are classified as organic, with the exception of: • Simple molecules and compounds: • Carbon dioxide • Carbon monoxide Most organic compounds contain C-H bonds (but Urea doesn’t)

In simple terms, organic molecules contain atoms from three elements: carbon, hydrogen, and oxygen • For example, glucose is organic, since its molecular formula is C6H12O6 • Carbon dioxide (CO2) is inorganic since it does not contain hydrogen. • Covalent bonds link carbon atoms together in long chains that form the skeletal framework for organic molecules. These carbon skeletons may vary with respect to: • Length • Shape (straight chain, branched, ring) • Number and location of double bonds • Other elements covalently bonded to available sites

Where is carbon on the periodic table?

Carbon has 4 valence electrons Therefore it can have bond with up to 4 other elements.

All organic molecules have two parts: The carbon backbone & the functional group • Tetravalence of carbon allows for complex arrangement of carbon compounds • Carbon atoms can form single, double, or triple covalent bonds

Hydrocarbon backbone Hydrocarbon chains form the skeleton of many macromolecules

What is a functional group? A group of atoms within a molecule that interacts in predictable ways with other molecules

Functional Groups (i) • The components of organic molecules that are most commonly involved in chemical reactions are known as functional groups • Each functional group behaves consistently from one organic molecule to another • FUNCTIONAL GROUPS give organic molecules their physical properties,their chemical reactivity, & solubility in aqueous solutions

Functional Groups (ii) • Functional groups are hydrophilic and increase the solubility of organic compounds in water • They are ionizable at physiological pH • Most possess electronegative atoms(N, P, O, S) • key bonds are :ester (C-O-C) & amide (O=C-N-)

Overview: The Molecules of Life • Within cells, small organic molecules join together to form larger molecules. • These large macromolecules may consist of thousands of covalently bonded atoms and weigh more than 100,000 daltons. • The four major classes of macromolecules are carbohydrates, lipids, proteins, and nucleic acids.

What is a hydrophilic molecule? A molecule that “loves” water H2O H2O

Macromolecules • Macromolecules are BIG MOLECULES • There are FOUR classes of BIOLOGICAL MACROMOLECULE: • Carbohydrates • Lipids • Proteins • Nucleic Acids

Macromolecules (with the exception of lipids) are POLYMERS • Polymers are big molecules, made up from the addition of lots of individual units • The individual units are called MONOMERS • Only 50 or so common monomers make up the thousands of macromolecules responsible for life • Polymers are distinguished by the different structore of their monomers • Just think how many words you can make out of the 26 letters of the alphabet….

Monomer v. Polymer H2O A monomer is a single molecular unit. A polymer is a long chain of many monomers. H2O

Most macromolecules are polymers built from monomers • Large organic molecules are polymers – long chains of repeating units that are either the same or similar to each other (monomers) • What distinguishes polymers is the different identities of their monomers (e.g. hydrocarbon portion on a lipid) • Reaction that creates polymers from monomers is called a condensation reaction, or dehydration reaction; 2 monomers are combined and one water molecule is released (exothermic) • Reverse reaction, when a polymer is broken down after the addition of water, is called hydrolysis (endothermic)

Monomer units join together via CONDENSATION REACTIONS

Breaking Down a macromolecule • Polymers are disassembled by a reaction that is the reverse of dehydration: HYDROLYSIS • Hydrolysis: (from Greek: break with water) Bonds between monomers are broken by the addition of water molecules, a hydrogen attaching to one monomer and a hydroxyl attaching to the other.

Breaking apart macromolecules

Condensation and Hydrolysis Reactions • hCondensation and hydrolysis

Carbon Compounds