BIOLOGY Chapter 2.3 THE CHEMICAL FOUNDATION OF LIFE CARBON
Living Organisms Forms complex molecules 4 valance electrons Carbon Atom Carbon can bond to four other atoms or groups of atoms, making a large variety of molecules possible.
Fig. 4-1 Living Organisms Forms complex molecules 4 valance electrons What are the 4 biological molecules??
Oparin & Haldane 1920 s Reducing atmosphere Energy from: Lighting Sunlight UV radiation Volcanoes Primitive soup
Fig. 4-2 Miller & Urey (1953) EXPERIMENT Water vapor CH 4 Atmosphere Electrode Condenser Cooled water containing organic molecules Cold water Jeffery Bada, Scripps 22 AA, 10 more H 2 O sea Sample for chemical analysis
The Miller-Urey experiment, shown below, a) showed that the conditions of early Earth were inhospitable to life b) demonstrated that amino acids and other organic molecules form under conditions that may have existed on Earth before life began c) proved that life could originate from inorganic chemicals d) both B and C
The Organic Molecules of Living Organisms Carbon, the building block of living things Comprises 18% of the body by weight Forms four covalent bonds Can form single or double bonds Can build micro- or macromolecules
Fig. 4-4 Carbon bonds with? Hydrogen (valence = 1) Oxygen (valence = 2) Nitrogen (valence = 3) Carbon (valence = 4) H O N C
Based on carbon s valence (4), how many different molecular shapes can be made from 6 carbons? A. 1 B. 2 C. 4 D. 6 E. more than 6
Fig. 4-3 Name Single or double bonds Molecular Formula Structural Formula Ball-and-Stick Model Space-Filling Model (a) Methane (b) Ethane (c) Ethene (ethylene)
Variation in carbon skeletons (a) Length (c) Double bond position Ethane Propane 1-Butene 2-Butene (b) Branching (d) Presence of rings Butane 2-Methylpropane (isobutane) Cyclohexane Benzene
Hydrocarbons C & H only release energy Nucleus Fat droplets 10 μm (a) Part of a human adipose cell (b) A fat molecule
Fig. 4-7a Isomers Same molecular formula, but differs with covalent bonding partner & properties Pentane 2-methyl butane (a) Structural isomers different covalent arrangements of their atoms
Fig. 4-7b Cis-Trans isomers (geometric) Differs in arrangement of R groups around dbl bond Must be two different groups on the C adjacent across cis isomer: The two Xs are on the same side. trans isomer: The two Xs are on opposite sides. (b) Geometric isomers
Enantiomers Mirror images, differs in shape due to asymmetric C 1 biologically active due to shape L isomer (c) Enantiomers D isomer
Figure 2.24 Molecules that have the same number and type of atoms arranged differently are called isomers. (a) Structural isomers have a different covalent arrangement of atoms. (b) Geometric isomers have a different arrangement of atoms around a double bond. (c) Enantiomers are mirror images of each other.
Enantiomers Drug Condition Effective Enantiomer Ineffective Enantiomer Ibuprofen Pain; inflammation S-Ibuprofen R-Ibuprofen Albuterol Asthma R-Albuterol S-Albuterol Amino acids & carbohydrates Examples: thalidomide, L-dopa
Chemical Group Compound Name Examples Hydroxyl group ( OH) Alcohol Ethanol Figure 2.27 Carbonyl group ( C=O) Ketone Aldehyde Carboxyl group ( COOH) Carboxylic acid, or organic acid Acetone Propanal Acetic acid Amino group ( NH 2 ) Amine Sulfhydryl group ( SH) Thiol Glycine Cysteine Phosphate group ( OPO 3 2 ) Organic phosphate Glycerol phosphate Methyl group ( CH 3 ) Methylated compound 5-Methyl cytosine
What functional group is commonly used in cells to transfer energy from one organic molecule to another? a) carboxyl b) sulfhydryl c) hydroxyl d) phosphate e) amino
The general structure of amino acids are shown in this figure. What functional groups are highlighted in salmon and yellow, respectively? a) Amino and carbonyl b) Hydroxyl and carbonyl c) Amino and carboxyl d) Methyl and carboxyl e) Methyl and hydroxyl
Fig. 4-9 Functional Groups
Fig. 4-UN4 ATP: An Important Source of Energy for Cellular Processes Reacts with H 2 O P P P Adenosine P i P P Adenosine Energy ATP Inorganic phosphate ADP Adenosine
Fig. 4-UN5 Reacts with H 2 O P P P Adenosine P i P P Adenosine Energy ATP Inorganic phosphate ADP
Fig. 4-UN6 Which molecule could be considered an aldehyde? A B
Fig. 4-UN7 Indicate the carbonyl group a b c d e
Fig. 4-UN13 Name the functional. A.Carbonyl B.Hydroxyl C.Sulfhydryl D.Carboxyl E.Amino