Macromolecules  Large Molecules  Macromolecules are formed when monomers are linked together to form longer chains called polymers.  The same process of making and breaking polymers is found in all living organisms.

 Consider some generic monomers with OH groups on their ends.  These monomers can be linked together by a process called dehydration synthesis (also called a condensation reaction) in which a covalent bond is formed between the two monomers while a water molecule is also formed from the OH groups.dehydration synthesis condensation reactioncovalent bond  This reaction is catalyzed by a polymerase enzyme.  This same type of condensation reaction can occur to form many kinds of polymers, from proteins to carbohydrates, nucleic acids to triglycerides. carbohydratesnucleic acids Condensation Reaction

Hydrolysis Reactions  Polymers of all sorts can be broken apart by hydrolysis reactions. In hydrolysis the addition of a water molecule (with the help of a hydrolase enzyme) breaks the covalent bond holding the monomers together.hydrolysis reactions

Four major types of Macromolecules  Lipids  Carbohydrates  Nucleic Acids  Proteins

Diverse groups of molecules in nonpolymorphic form  Lipids  Carbohydrates  Nucleic Acids  Proteins Sugars Nucleotides Amino Acids Four major types of Macromolecules

Proteins  Proteins consist of one or more polymers called polypeptides, which are made by linking amino acids together with peptide linkages. Proteinspolymerspolypeptidesamino acids  Peptide linkages are formed through condensation reactions. Peptide linkages condensation reactions  All proteins are made from the same 20 amino acids.  Different amino acids have different chemical properties.

Proteins  Protein’s primary structure largely determines its secondary, tertiary (and quaternary) structure.primary structuresecondarytertiaryquaternary  Proteins subjected to extreme conditions (large changes in pH, high temperatures, etc.) often denature.  Proteins act as enzymes, and catalyze very specific chemical reactions.enzymes

Proteins

Carbohydrates  Carbohydrates are always composed of carbon, hydrogen and oxygen molecules Carbohydrates  Monosaccharides typically have five or six carbon atoms. Monosaccharides  Monosaccharides can, such as the ribose and deoxyribose of RNA and DNA, can serve very important functions in cells.

Carbohydrates  Condensation reactions form covalent bonds between monosaccharides, called glycosidic linkages.glycosidic linkages  Monosaccharides are the monomers for the larger polysaccharides.  Polysaccharides play various roles, from energy storage (starch, glycogen) to structure (cellulose). Polysaccharides

Nucleic Acid  Two types of nucleic acids:nucleic acids DNA RNA  DNA stores the genetic information of organisms; RNA is used to transfer that information into the amino acid sequences of proteins.  DNA and RNA are polymers composed of subunits called nucleotides. nucleotides  Nucleotides consist of a five-carbon sugar, a phosphate group and a nitrogenous base.  Five nitrogenous bases found in nucleotides: the purines  adenine (A)  guanine (G) the pyrimidines  cytosine (C)  thymine (T) (DNA only)  uracil (U) (RNA only)

Nucleic Acid  DNA is transmitted from generation to generation with high fidelity, and therefore represents a partial picture of the history of life.

Nucleic Acid

Lipids  Lipids constitute a very diverse group of molecules that all share the property of being hydrophobic. Lipidshydrophobic  Fats and oils are lipids generally associated with energy storage. Fatsoils  Fatty acids, which make up fats and oils, can be saturated or unsaturated, depending on the absence or presence of double bonded carbon atoms. Fatty acids  Other types of lipids are used for a other purposes, including pigmentation (chlorophyll, carotenoids), repelling water (cutin, suberin, waxes) and signaling (cholesterol and its derivatives).

Lipids  Lipids are joined together by ester linkages. Lipidsester linkages  Triglyceride is composed of 3 fatty acid and 1 glycerol molecule  Fatty acids attach to Glycerol by covalent ester bond  Long hydrocarbon chain of each fatty acid makes the triglyceride molecule nonpolar and hydrophobic

Lipids

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