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.

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.

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.

Four major types of Macromolecules

Lipids Carbohydrates Nucleic Acids Proteins

Diverse groups of molecules in nonpolymorphic form Lipids

Carbohydrates Nucleic Acids Proteins

SugarsNucleotides

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.

Peptide linkages are formed through 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.

Proteins subjected to extreme conditions (large changes in pH, high temperatures, etc.) often denature.

Proteins act as enzymes, and catalyze very specific chemical reactions.

Proteins

Carbohydrates Carbohydrates are always composed

of carbon, hydrogen and oxygen molecules

Monosaccharides typically have five or six carbon atoms.

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.

Monosaccharides are the monomers for the larger polysaccharides.

Polysaccharides play various roles, from energy storage (starch, glycogen) to structure (cellulose).

Nucleic Acid Two types of 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 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. Fats and oils are lipids generally associated with

energy storage. Fatty acids, which make up fats and oils, can be

saturated or unsaturated, depending on the absence or presence of double bonded carbon atoms.

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. 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

THANK YOU!