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