AP Bio Chapter 3

Living organisms consist of mostly carbon-based compounds A compound containing carbon (and hydrogen) is said to be an organic compound4 main classes of all living things (critically important molecules) Carbohydrates Lipids Proteins Nucleic Acids ** can form huge molecules called macromolecules Hydrocarbons: organic molecules- hydrogen and carbon only Fats have hydrocarbon components Can undergo reactions that release a lot of energy Functional Groups: the chemical groups that affect molecular function by being directly involved in chemical reactions 7 Most Important Functional Groups: Hydroxyl Group -OH Carbonyl Group >C=O Carboxyl Group -COOH Amino Group -NH2 Sulfhydryl Group -SH Phosphate Group -OPO3-2 Methyl Group -CH3 Hydroxyl Group:

Carbonyl Group:

Carboxyl Group:

Amino Group:

Sulfhydryl Group:

Phosphate Group:

Methyl Group:

Polymer: a long molecule consisting of many similar building blocks These small building block molecules are called monomers Dehydration reaction: when 2 monomers bond together through the loss of a water molecule Hydrolysis: polymers are disassembled to monomers; reverse of dehydration reaction **These processes are facilitated by enzymes–catalysts–speed up chemical reactions Carbohydrates: include sugars and the polymers of sugars Simplest carbs are monosaccharides (simple sugars) Carb macromolecules are polysaccharides Monosaccharides: molecular formulas usually multiples of CH₂O Glucose most common monosaccharide (C₆H₁₂O₆) Classified by # of carbons on carbon skeleton and placement of carbonyl group Disaccharide: formed when a dehydration reaction joins 2 monosaccharides This covalent bond is a glycosidic linkage Polysaccharides: polymers of sugar– storage and structural roles Structure and function of a polysaccharide are determined by its sugar monomers and positions of glycosidic linkages Starch (amylose): an energy storage polysaccharide of plants Glycogen: short term energy storage polysaccharide in animals Cellulose: a major component of the tough wall of plant cells (plant cell walls) cellulose in human food passes through the digestive tract as insoluble fiber– humans can’t digest it Chitin: structural polysaccharide- exoskeleton of arthropods–cell wall support for many fungi POLYSACCHARIDE SUMMARY: Starch: storage in plants Glycogen: storage in animals Cellulose: structural in plants Chitin: structural in anthropods and fungi **all have glycosidic linkage bonding monomers of glucose Lipids: long-term energy storage, insulation, cell membrane, communication -ALL NONPOLAR AND HYDROPHOBIC (hydrophobic b/c they’re nonpolar) Lipids do not form true polymers Unifying feature of lipids is having little or no affinity for water Fats: Triglyceride Triglycerol and 3 fatty acids ** bond between fatty acids and backbone called ESTER LINKAGE Saturated fatty acids: have the maximum number of hydrogen atoms possible and NO double bonds -solid at room temperature -found in animals (homeotherms) Unsaturated fatty acids: have one or more double bonds -liquid at room temperature -found in plants, fish (any cold blooded animal)

Phospholipids: two fatty acids and a phosphate group are attached to glycerol -make up cell membrane -two fatty acid tails are hydrophobic, but -phosphate head and 2 2 fatty acid tails

Steroids: Carbon skeleton consisting of four fused rings Cholesterol and sex hormones (testosterone and estrogen) Characterized by 4 fused rings (glycosidic bond between each monomer)

NUCLEIC ACIDS: Genes are made of DNA, and a nucleic acid is made of monomers called nucleotides Give instructions for building proteins 2 types of nucleic acids -Deoxyribonucleic acid (DNA) -Ribonucleic acid (RNA) Polymer: RNA and DNA Monomer: nucleotide

Nitrogen bases classified by the number of rings -purines 2 rings– adenine and guanine -pyrimidines 1 ring– thymine, cytosine, and uracil (RNA)

Phosphodiester bond (each nucleotide held together by this bond) Forming between phosphate group of one nucleotide and bicarbonate sugar on the other nucleotide

**DNA IS AN ANTIPARALLEL MOLECULE

Proteins–functions —>everything except carrying genetic information ^ polymer Monomer - amino acid

R group: variable group, side chain (there are 20 different R groups) Peptide Bond

Peptide: many amino acids linked by a peptide bond POLYPEPTIDE ≠ PROTEIN **sweater analogy KNOW LEVELS OF PROTEINS -primary: its unique sequence of amino acids (dictated by DNA), held together by peptide bonds -secondary- found in most proteins, consists of coils and folds in the polypeptide chain, due to hydrogen bonding; Alpha helix, Beta pleated sheet -tertiary- 3D globular structure formed by interactions between R groups +when these R groups interact, it’s due to hydrogen bonds, ionic bonds, hydrophobic interactions, disulfide bridges, and Van der Waals interactions -quaternary (sometimes)- protein consisting of two or more polypeptide chains– association of 2 or more subunits ** the bonds are the same as in the third level!!!! Chaperonins: protein molecules that assist the proper folding of other proteins Denaturation: changing shape (protein won't work w/o correct shape)-- why chaperonins are so important