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. Chapter 4: Life is based on molecules with carbon (organic molecules) organic compounds organic compounds isomers isomers functional groups functional.

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Presentation on theme: ". Chapter 4: Life is based on molecules with carbon (organic molecules) organic compounds organic compounds isomers isomers functional groups functional."— Presentation transcript:

1 . Chapter 4: Life is based on molecules with carbon (organic molecules) organic compounds organic compounds isomers isomers functional groups functional groups

2 . Much of the chemistry of life is based on organic compounds organic compounds have at least one carbon atom covalently bound to either: organic compounds have at least one carbon atom covalently bound to either: another carbon atom another carbon atom or to hydrogen or to hydrogen the chemistry of organic molecules is organized around the carbon atom the chemistry of organic molecules is organized around the carbon atom

3 . Discuss the chemistry of carbon. How does it typically bond? What does it typically bond to? What sort of shapes, angles, freedoms, etc. are associated with the bonds that it makes? Draw a tetrahedron.

4 . Organic Compounds carbon atoms have six electrons – carbon atoms have six electrons – 2 in level 1 2 in level 1 4 in their valence (outer) shell (level 2) 4 in their valence (outer) shell (level 2) carbon is not a strongly electron seeking element, and it does not readily give up its electrons; therefore: carbon is not a strongly electron seeking element, and it does not readily give up its electrons; therefore: carbon does not readily from ionic bonds carbon does not readily from ionic bonds it almost always forms covalent bonds it almost always forms covalent bonds carbon can form up to 4 covalent bonds (and typically does form all four) carbon can form up to 4 covalent bonds (and typically does form all four)

5 . Organic Compounds wide diversity in organic compounds wide diversity in organic compounds over 5 million identified over 5 million identified variety partially because carbon tends to bond to carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus variety partially because carbon tends to bond to carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus hydrocarbons – contain only hydrogen and carbon hydrocarbons – contain only hydrogen and carbon single carbon-carbon bonds allow rotation around them and lend flexibility to molecules single carbon-carbon bonds allow rotation around them and lend flexibility to molecules

6 . Organic Compounds building of organic macromolecules also leads to diversity building of organic macromolecules also leads to diversity carbon works well as a molecular “backbone” for forming long chain molecules carbon works well as a molecular “backbone” for forming long chain molecules stronger carbon-carbon bonds can be made with double and triple covalent bonds stronger carbon-carbon bonds can be made with double and triple covalent bonds carbon chains can branch carbon chains can branch

7 . Organic Compounds the shape of a molecule is important in determining its chemical and biological properties the shape of a molecule is important in determining its chemical and biological properties When 4 separate bonds are formed by carbon… When 4 separate bonds are formed by carbon… formed at degree angles formed at degree angles form a pyramid with a triangular base called a tetrahedron form a pyramid with a triangular base called a tetrahedron When double bonds are formed… When double bonds are formed… angles are 120 or 180 degrees apart, and they all lie in the same plane angles are 120 or 180 degrees apart, and they all lie in the same plane

8 . Organic Compounds bond angles for carbon play a critical role in determining the shape of molecules bond angles for carbon play a critical role in determining the shape of molecules generally there is freedom to rotate around carbon to carbon single bonds but not double (or triple) bonds generally there is freedom to rotate around carbon to carbon single bonds but not double (or triple) bonds

9 . Discuss the chemistry of carbon. How does it typically bond? What does it typically bond to? What sort of shapes, angles, freedoms, etc. are associated with the bonds that it makes? Draw a tetrahedron.

10 . Chapter 4: Life is based on molecules with carbon (organic molecules) organic compounds organic compounds isomers isomers functional groups functional groups

11 . Discuss isomers. What are they? What is the difference between structural isomers and stereoisomers? Between cis-trans isomers and enantiomers? Draw an example of each of these: structural isomers cis-trans isomers enantiomers

12 . What type of isomer situation is this? How do you know?

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18 .Isomers have the same molecular formula have the same molecular formula have different structures have different structures there are two kinds of isomers there are two kinds of isomers structural isomers structural isomers stereoisomers stereoisomers

19 .Isomers structural isomers - substances with the same molecular formula that differ in the covalent arrangement of their atoms structural isomers - substances with the same molecular formula that differ in the covalent arrangement of their atoms example: ethanol and dimethyl ether (C 2 H 6 O) example: ethanol and dimethyl ether (C 2 H 6 O)

20 .Isomers stereoisomers - substances with the same arrangement of covalent bonds, but the order in which the atoms are arranged in space is different stereoisomers - substances with the same arrangement of covalent bonds, but the order in which the atoms are arranged in space is different two types: enantiomers and diastereomers two types: enantiomers and diastereomers

21 .Isomers cis-trans isomers – diastereomers associated with compounds that have carbon-carbon double bonds cis-trans isomers – diastereomers associated with compounds that have carbon-carbon double bonds since there is no rotation around the double bond the other atoms attached to the carbons are stuck in place in relationship to each other since there is no rotation around the double bond the other atoms attached to the carbons are stuck in place in relationship to each other larger items together = cis; larger items opposite = trans larger items together = cis; larger items opposite = trans examples: trans-2-butene and cis-2-butene examples: trans-2-butene and cis-2-butene

22 .Isomers enantiomers – substances that are mirror images of each other and that cannot be superimposed on each other enantiomers – substances that are mirror images of each other and that cannot be superimposed on each other sometimes called optical isomers (kind of a loose term, though) sometimes called optical isomers (kind of a loose term, though)

23 .Isomers typically, only one form of an enatiomer pair is found in and/or used by organisms typically, only one form of an enatiomer pair is found in and/or used by organisms the enantiomers are given designations such as the enantiomers are given designations such as [(+)- vs. (−)-] or [D- vs. L-] or [(R)- vs. (S)-] biologically important enantiomers include biologically important enantiomers include amino acids (found in proteins) – most are L-amino acids amino acids (found in proteins) – most are L-amino acids (e.g. L-leucine, L-alanine, etc) sugars – most are D-sugars sugars – most are D-sugars (e.g. D-glucose, D-fructose, etc.)

24 . Discuss isomers. What are they? What is the difference between structural isomers and stereoisomers? Between cis-trans isomers and enantiomers? Draw an example of each of these: structural isomers cis-trans isomers enantiomers

25 . Chapter 4: Life is based on molecules with carbon (organic molecules) organic compounds organic compounds isomers isomers functional groups functional groups

26 . What is a functional group, and why is it useful to know them? Quiz each other on the names and chemistry of the functional groups in the notes.

27 . Functional Groups functional groups determine most of the reactive properties (functions) of organic molecules functional groups determine most of the reactive properties (functions) of organic molecules functional groups are groups of atoms covalently bonded to a carbon backbone that give properties different from a C-H bond functional groups are groups of atoms covalently bonded to a carbon backbone that give properties different from a C-H bond the properties of the major classes of organic compounds (carbohydrates, lipids, proteins, and nucleic acids) are determined mostly by their functional groups the properties of the major classes of organic compounds (carbohydrates, lipids, proteins, and nucleic acids) are determined mostly by their functional groups learn the seven functional groups on the following slides learn the seven functional groups on the following slides

28 . Functional Groups

29 . hydroxyl group: polar; found in alcohols hydroxyl group: polar; found in alcohols carbonyl group: polar; found in aldehydes and ketones carbonyl group: polar; found in aldehydes and ketones carboxyl group: weakly acidic; found in organic acids (such as amino acids) carboxyl group: weakly acidic; found in organic acids (such as amino acids)

30 . Functional Groups amino group: weakly basic; found in such things as amino acids amino group: weakly basic; found in such things as amino acids sulfhydryl group: essentially nonpolar; found in some amino acids sulfhydryl group: essentially nonpolar; found in some amino acids phosphate group: weakly acidic; found in such things as phospholipids and nucleic acids phosphate group: weakly acidic; found in such things as phospholipids and nucleic acids methyl group: nonpolar (thus hydrophobic); found in such things as lipids, other membrane components methyl group: nonpolar (thus hydrophobic); found in such things as lipids, other membrane components P


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