Question

Which type of polymer is formed from each of the following monomers: (a) amino acids; (b) alkenes; (c) simple sugars; (d) mononucleotides?

Short answer

Proteins (a), Polyalkenes (b), Polysaccharides (c), Nucleic acids (d).

Step-by-step solution

Identify the Polymer for Amino Acids

Amino acids are organic compounds that contain both amino and carboxyl groups. When multiple amino acids bond together through peptide bonds, they form a type of polymer known as proteins or polypeptides.

Identify the Polymer for Alkenes

Alkenes are hydrocarbons that contain carbon-carbon double bonds. When alkenes polymerize through addition reactions, they form polymers known as polyalkenes or polyolefins. An example is polyethylene, formed from the polymerization of ethene.

Identify the Polymer for Simple Sugars

Simple sugars, also known as monosaccharides, can bond together through glycosidic linkages to form polysaccharides. Common examples of polysaccharides include starch, cellulose, and glycogen.

Identify the Polymer for Mononucleotides

Mononucleotides, which are the basic units of nucleic acids, link together through phosphodiester bonds to form polymers such as DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).

Key concepts

Amino Acids

Amino acids are the building blocks of proteins. They have a basic structure of an amino group (-NH2) and a carboxyl group (-COOH) attached to a central carbon atom. Each amino acid also has a unique side chain (R group) that defines its characteristics. When amino acids link together through peptide bonds, they form long chains called proteins or polypeptides.
Proteins play crucial roles in our bodies including acting as enzymes, hormones, and structural components. They are essential for growth, repair, and the overall function of our cells.

Alkenes

Alkenes are hydrocarbons that contain at least one carbon-carbon double bond (C=C). This double bond is reactive and allows alkenes to undergo addition reactions. During polymerization, alkenes react to form long-chain polymers called polyalkenes or polyolefins. A common example is polyethylene, which is formed by polymerizing the alkene ethene (C2H4).
Polyalkenes are widely used in the production of plastics, packaging materials, and various consumer goods. The versatility and durability of these polymers make them important materials in everyday life.

Simple Sugars

Simple sugars, or monosaccharides, are the simplest form of carbohydrates. Examples include glucose, fructose, and galactose. These sugars can join together through glycosidic linkages to form more complex carbohydrates known as polysaccharides. Common polysaccharides include starch, cellulose, and glycogen.
Polysaccharides have various functions in living organisms:

• Starch – A storage form of energy in plants.
• Cellulose – A structural component of plant cell walls.
• Glycogen – A storage form of energy in animals and humans.

These molecules are vital to the structure and energy management of cells.

Mononucleotides

Mononucleotides are the basic units of nucleic acids like DNA and RNA. Each mononucleotide comprises a nitrogenous base, a five-carbon sugar, and a phosphate group. In forming DNA or RNA, mononucleotides link together through phosphodiester bonds, creating long chains called polynucleotides.
DNA and RNA are essential for genetic information storage and transfer in all living organisms.

• DNA (deoxyribonucleic acid) – Stores genetic information used in development and functioning.
• RNA (ribonucleic acid) – Helps in translating genetic information from DNA to synthesize proteins.

Understanding these molecules is fundamental for studying genetics and cellular biology.