Problem 90 - Chemistry Matter and Change

Question

List the names of the monomers that make up proteins, complex carbohydrates, and nucleic acids.

Step-by-Step Solution

Answer

The monomers that make up proteins are amino acids, which are composed of 20 different types. The monomers that make up complex carbohydrates are monosaccharides, such as glucose, fructose, and galactose. The monomers that make up nucleic acids are nucleotides, which consist of a sugar, a phosphate group, and a nitrogenous base (A, G, C, T for DNA, and A, G, C, U for RNA).

Step 1: Monomers of Proteins

The monomers that make up proteins are called amino acids. There are 20 different amino acids that can be combined to form proteins. Each amino acid has a unique side chain or R-group, which gives it specific properties, such as charge and polarity.

Step 2: Monomers of Complex Carbohydrates

The monomers that make up complex carbohydrates are called monosaccharides. Examples of monosaccharides include glucose, fructose, and galactose. These single sugar units can be combined to form disaccharides, such as sucrose (glucose + fructose) and lactose (glucose + galactose), or larger polymers such as starch, cellulose, and glycogen, which are all composed of glucose subunits.

Step 3: Monomers of Nucleic Acids

The monomers that make up nucleic acids are called nucleotides. A nucleotide consists of three components: a sugar (either ribose or deoxyribose), a phosphate group, and a nitrogenous base. There are five nitrogenous bases: adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U). In DNA, the bases are A, G, C, and T, while in RNA, the bases are A, G, C, and U.

Key Concepts

Amino Acids

Amino acids are the building blocks of proteins, which are vital macromolecules in biological systems. Proteins perform various functions including structural support, catalyzing biochemical reactions, and regulating bodily processes. Amino acids link together to form proteins through peptide bonds, creating long chains called polypeptides.

Each amino acid consists of a central carbon atom bonded to four different groups: an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom, and a distinctive side chain known as the R-group. It’s this R-group that makes each of the 20 amino acids unique, imparting different characteristics like size, charge, and hydrophobicity.

• Common examples include: glycine, alanine, lysine, and glutamic acid.
• Small changes in the sequence of amino acids can lead to significant differences in a protein's function.
• Some amino acids are "essential," meaning humans must obtain them from their diet.

Understanding amino acids is fundamental to studying how proteins function and interact within cells.

Monosaccharides

Monosaccharides are the simplest form of carbohydrates and serve as fundamental building blocks for more complex sugars and carbohydrates in our diet. Often referred to as simple sugars, they are crucial for energy storage and metabolism.

These monomers can exist in linear or ring-shaped structures and include:

• Glucose: A primary energy source for cells.
• Fructose: Found in fruits and honey.
• Galactose: Partner to glucose in forming lactose, the sugar in milk.

Monosaccharides bond through glycosidic linkages to form disaccharides like sucrose and lactose, or polysaccharides like starch and cellulose.

Not only do they provide immediate energy, but they also play a crucial role in forming essential biomolecules and cellular structures. Understanding these sugars is key to grasping how our body manages energy and the importance of carbohydrates in our diet.

Nucleotides

Nucleotides are the monomers that make up nucleic acids, which are essential for storing and transmitting genetic information. These molecules form the backbone of DNA and RNA, the blueprints for cellular functions and heredity.

Each nucleotide comprises:

• a sugar molecule (ribose in RNA and deoxyribose in DNA),
• a phosphate group,
• and a nitrogenous base.

The nitrogenous bases come in five varieties: adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U).

DNA utilizes A, G, C, and T, and is known for its double helix structure, while RNA contains A, G, C, and U and usually exists as a single strand.

• These bases pair to form the "steps" of the nucleic acid "ladder": A with T (or U in RNA), and C with G.
• Nucleotides are not just passive carriers of genetic code, but also play roles in cellular energy transfer (like ATP) and signal transduction (like cyclic AMP).

Grasping the structure of nucleotides is essential for understanding molecular biology and genetics.