Chapter 3

Organic Compounds Hydrogen and other elements covalently bonded to carbon  Carbohydrates  Lipids  Proteins  Nucleic Acids

Bonding Arrangements  Carbon atoms can form chains or rings  Carbon can form 3 dimensional molecules  Other atoms project from the carbon backbone

or p.34e Simplified structural formula for a six-carbon ring icon for a six-carbon ring Organic Compounds

Fig. 3-2, p.35 Organic Compounds

Functional Groups  Atoms or clusters of atoms covalently bonded to carbon backbone  Give organic compounds their different properties

Examples of Functional Groups Hydroxyl group - OH Amino group- NH 3 + Carboxyl group- COOH Phosphate group- PO 3 - Sulfhydryl group- SH

 Estrogen and testosterone are hormones responsible for observable differences in traits between male and female wood ducks  Differences in position of functional groups attached to ring structure (pg 36) Functional Groups in Hormones An EstrogenTestosterone

Fig. 3-5b, p.36

Common Functional Groups in Biological Molecules Fig. 3-4, p.36

Directionality influences structure and function of a polymer. Fig. 3-4, p.36

Types of Reactions  Functional group transfer  Electron transfer  Rearrangement  Condensation  Cleavage

Condensation Reactions  Form polymers from subunits  Enzymes remove -OH from one molecule, H from another, bond the two molecules  Discarded atoms can join to form water

Condensation Fig. 3-6a, p.38

Hydrolysis  cleavage reaction  Breaks polymers  Enzymes split molecules into two or more parts  An -OH and an H from water attached at exposed sites

Hydrolysis Fig. 3-6b, p.38

Carbohydrates Monosaccharides Monosaccharides (simple sugars) Oligosaccharides (short-chain carbohydrates) Polysaccharides (complex carbohydrates)

Monosaccharides  Simplest carbohydrates  Most are sweet tasting, water soluble  Most have 5- or 6-carbon backbone Glucose (6 C)Fructose (6 C) Ribose (5 C)Deoxyribose (5 C)

Two Monosaccharides glucosefructose Fig. 3-7, p.38

Disaccharides  Type of oligosaccharide  Formed by condensation reaction + H 2 O glucosefructose sucrose Fig. 3-7b, p.38

Polysaccharides  Straight or branched chains of many sugar monomers  Nature of bonding between subunits determines secondary structure of the carbohydrate  Most common are composed entirely of glucose Cellulose Cellulose Starch Starch Glycogen Glycogen

Glycogen  Sugar storage form in animals  Large stores in muscle and liver cells  When blood sugar decreases, liver cells degrade glycogen, release glucose Fig. 3-9, p.38

Chitin  Polysaccharide  Nitrogen-containing groups attached to glucose monomers  Structural material for hard parts of invertebrates, cell walls of many fungi

Chitin  Chitin occurs in protective body coverings of many animals, including ticks (pg 39) Fig. 3-10a, p.39

Fig. 3-10b, p.39 Chitin

 Most include fatty acids Fats Fats Phospholipids Phospholipids Waxes Waxes  Sterols and derivatives have no fatty acids  Insoluble in water Lipids

Fats  Fatty acid(s) attached to glycerol  Triglycerides are most common Fig. 3-12, p.40

Fatty Acids  Carboxyl group (-COOH) at one end  Carbon backbone (up to 36 C atoms) Saturated - Single bonds between carbons Saturated - Single bonds between carbons Unsaturated - One or more double bonds Unsaturated - One or more double bonds

Three Fatty Acids Fig. 3-11, p.40

Phospholipids  Main components of cell membranes

hydrophilic head two hydrophobic tails Fig. 3-13, p.41

Waxes  Long-chain fatty acids linked to long chain alcohols or carbon rings  Important in water-proofing

Waxes  Bees construct honeycombs from their own waxy secretions Fig. 3-14, p.41

Sterols and Derivatives  No fatty acids  Rigid backbone of four fused carbon rings  Cholesterol - most common type in animals Fig. 3-14, p.41

Amino Acid Structure amino group carboxyl group R group

Properties of Amino Acids  Determined by the “R group” May be hydrophobic, hydrophilic, ionic May be hydrophobic, hydrophilic, ionic  Amino acids may be: Polar or Non-polar Polar or Non-polar Uncharged or charged (+ or -) Uncharged or charged (+ or -)

Protein Synthesis  Protein - chain of amino acids linked by peptide bonds  Peptide bond covalent covalent amino group of one amino acid links with carboxyl group of next amino group of one amino acid links with carboxyl group of next

Fig. 3-15b, p.42

Fig. 3-15c, p.42

Fig. 3-15d, p.42

Fig. 3-15e, p.42

Levels of Structure in Proteins  Primary Structure - Amino Acid Sequence  Secondary Structure - Small scale shape  Tertiary Structure - Large scale shape  Quaternary Structure - Combination of multiple Polypeptide chains

 Primary structure influences shape : Allows hydrogen bonds to form between different parts of chain Allows hydrogen bonds to form between different parts of chain Puts R groups in positions allowing them to interact Puts R groups in positions allowing them to interact Primary Structure & Protein Shape

Secondary Structure H+ bonds often create coiled, pleated, or extended pattern

Examples of Secondary Structure

Tertiary Structure Folding as a result of interactions between R groups heme group coiled and twisted polypeptide chain of one globin molecule

Quaternary Structure Multiple polypeptide chains Multiple polypeptide chains Hemoglobin

heme alpha globin beta globin Fig. 3-17, p.44

Polypeptides with Attached Organic Compounds  Lipoproteins Proteins combined with cholesterol, triglycerides, phospholipids Proteins combined with cholesterol, triglycerides, phospholipids  Glycoproteins Proteins combined with oligosaccharides Proteins combined with oligosaccharides

Denaturation  Breakage of weak bonds disrupts three- dimensional shape  Causes: pH pH Temperature Temperature  disrupts function

Fig. 3-18c, p.45

VALINE HISTIDINELEUCINETHREONINEPROLINEVALINEGLUTAMATE b One amino acid substitution results in the abnormal beta chain in HbS molecules. During protein synthesis, valine was added instead of glutamate at the sixth position of the growing polypeptide chain. Fig. 3-18b, p.45

 Know the basic structure of DNA and RNA  Know the structure of a nucleotide Nucleic acids

Nucleotide Functions  Energy carriers  Coenzymes  Chemical messengers  Building blocks for nucleic acids

ATP - A Nucleotide three phosphate groups sugar base

Nucleic Acids Adenine Cytosine

DNA

RNA  Usually single strands  uracil in place of thymine

Fig. 3-22, p.49

Fig. 3-23, p.49