Chapter 4: Carbon and Molecular Diversity of Life PDF

Chapter 4: Carbon and the Molecular Diversity of Life Objectives 1. You will know how carbon is cycled through the biosphere and know the chemical reaction responsible for that cycle. 2. You will memorize the “ingredients” of life. 3. You will know why carbon is so versatile 4. Y...

Chapter 4: Carbon and the Molecular Diversity of Life Objectives 1. You will know how carbon is cycled through the biosphere and know the chemical reaction responsible for that cycle. 2. You will memorize the “ingredients” of life. 3. You will know why carbon is so versatile 4. You will know the difference between hydrocarbons and carbon skeletons. 5. You will know the 3 types of isomers and be able to identify their chemical structures. You should also know why isomers are important in pharmacology. 6. You will describe the 7 functional groups, the compound names and their characteristics. Carbon  Carbon enters the biosphere through the action of producers  Sunlight powers the conversion of carbon dioxide and water to glucose and oxygen  Molecules such as glucose are taken up by consumers Ingredients of life  Hydrogen, Oxygen, Sulfur, Phosphorus, and Nitrogen are common elements that form bonds with carbon  Overall percentage of these elements are quite uniform from one organism to another  Suggests there might be some common evolutionary origin Stanley Miller’s Experiment Stanley Miller’s Experiment  Conditions with no life could produce molecules typically associated with life (made and used by living things)  For example: amino acids (building blocks of proteins)  Supported the hypothesis that: Organic molecules can be synthesized abiotically under conditions that may have existed on early Earth  Perhaps life could originate from conditions that previously had no life Carbon can bond to four atoms 6  Carbon has 6 electrons C 12  2 electrons in first shell  4 electrons in second shell (valence)  Each of the 4 electrons can be shared (covalent) with 4 different atoms Carbon can bond to four atoms  Carbon can form bonds with 4 different atoms making a large variety of molecules possible  The complexity and variety of organic molecules is due to the chemical versatility of carbon atoms  This property is key for forming chemical groups (important for biological functions) Carbon can bond to four atoms  Carbon can form bonds with other atoms such as carbon  For example: Ethane  Carbon can form double covalent bonds such as carbon and oxygen  For example: Ethylene, carbon dioxide O=C=O  Carbon can form triple bonds  For example: hydrogen cyanide Hydrocarbons  The most common atom that carbon bonds is hydrogen  These can form long chains of carbon and hydrogen (hydrocarbons, non polar)  Can even form rings  Not common in living things  Carbon skeleton  Carbon and hydrogen form a “skeleton” that other atoms can bond to in living things  Even a long carbon-hydrogen chains can exist in living things if they bond with “living” atoms  For example: fat droplets  Isomers  In this complexity of carbon-hydrogen skeletons we see compounds that have the same # of carbon and hydrogens but have different structures (isomers)  Structural isomers  Cis-trans isomers  Enantiomers isomers Structural Isomers  Two compounds that are different in their arrangement of covalent bonds  Some carbons may have formed bonds with different atoms (compounds are different!)  For example: Cis and trans Isomers  Carbon formed bonds with the same atoms but their location is different (but the two compounds are still the same  For example: Cis: if atoms are Trans: if atoms are the same side of the opposite side of the double bond the double bond Cis and trans Isomers? Cis: if atoms are Trans: if atoms are the same side of the opposite side the double bond of the double bond Enantiomers  Isomers that have the same carbon atoms forming bonds with the same atoms but are mirror images of each other  For example:  Enantiomers are important in pharmacology Effective Ineffective Drug Effects Enantiomer Enantiomer Reduces Ibuprofen inflammation and pain Functional groups  Chemical groups that form parts of a compound and change the properties of the carbon “skeleton”  For example: fat droplets  Groups consist of carbon, hydrogen, oxygen, nitrogen, sulfur, or phosphorous  There are 7 important groups in biology  Hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, phosphate, and methyl Functional group: Hydroxyl  -OH (also HO-)  Compound name: alcohol  Characteristics: 1. polar (because of oxygen) 2. can form hydrogen bonds  For example: ethanol Functional group: Carbonyl  -C=O  Compound name: ketone, aldehyde  Characteristics:1.ketone (if the group is within the carbon skeleton) 2.aldehyde For example: Functional group: Carboxyl  -COOH  Compound name: carboxylic acid  Characteristics: can act as an acid  For example: acetic acid Functional group: Amino  -NH2  Compound name: amine  Characteristics: can act as a base  For example: glycine (amino acid) Functional group: Sulfhydryl  -SH  Compound name: Thiol  Characteristics: can form crosslinks or “bridges”that help stabilize a protein  For example: cysteine Functional group: Phosphate  -OPO32- (only group with P)  Compound name: _______ phosphate  Characteristics: 1. adds a negative charge to compound (protein for example) 2. reacts with water  For example: glyercol phoshate Functional group: Methyl  -CH3  Compound name: methyl_________  Characteristics: 1. can bind to DNA 2. change the shape/function of hormones  For example: 5-methylcytosine