Question

What general name is given to sugars containing five carbon atoms? six carbon atoms? three carbon atoms?

Short answer

Sugars containing five carbon atoms are called pentoses, those containing six carbon atoms are called hexoses, and those with three carbon atoms are called trioses.

Step-by-step solution

Identifying the general name for sugars with five carbon atoms

Sugars with five carbon atoms are generally called pentoses. The "pent-" prefix signifies that there are five carbon atoms in the sugar molecule, and the "-ose" suffix indicates that it is a sugar.

Identifying the general name for sugars with six carbon atoms

Sugars with six carbon atoms are generally called hexoses. The "hex-" prefix signifies that there are six carbon atoms in the sugar molecule, and the "-ose" suffix indicates that it is a sugar.

Identifying the general name for sugars with three carbon atoms

Sugars with three carbon atoms are generally called trioses. The "tri-" prefix signifies that there are three carbon atoms in the sugar molecule, and the "-ose" suffix indicates that it is a sugar.

Key concepts

Pentoses

Pentoses are a type of monosaccharide, or simple sugar, characterized by having five carbon atoms. The name "pentose" comes from the prefix "pent-," meaning five. Pentoses play critical roles in biology, particularly as components of nucleic acids.

• In nucleic acids: Both RNA and DNA contain pentoses. RNA has ribose, and DNA has deoxyribose as their sugar backbone. These sugars are essential for the structure and function of genetic material.
• In metabolism: Ribose is a crucial part of many coenzymes, like ATP and NADP, that are pivotal in various metabolic processes.
• As intermediates: In cellular metabolic pathways such as the pentose phosphate pathway, pentoses are involved in the synthesis of nucleotides and amino acids.

Ribose and deoxyribose are the most well-known pentoses, but other less common ones include arabinose and xylose, which can also be found in plant-derived substances.

Hexoses

Hexoses are monosaccharides with six carbon atoms, and they are among the most important sugars in biology. The prefix "hex-" signifies six, and together with "-ose," it indicates that these carbohydrates are sugars.

• Common hexoses: The most familiar hexoses are glucose, fructose, and galactose. These sugars are fundamental in energy production and storage within organisms.
• In energy production: Glucose is a primary energy source in cells, especially through the glycolysis and the Krebs cycle, which ultimately produces ATP, the energy currency of the cell.
• Structural components: In nature, hexoses are involved in forming larger carbohydrates like starch, cellulose, and glycogen, which serve as energy reserves or structural materials.

Fructose, often found in fruits, and galactose, a part of lactose in milk, are also vital principles in diet and biochemical pathways.

Trioses

Trioses are the smallest monosaccharides in terms of carbon atoms, containing just three carbon atoms. The "tri-" prefix denotes three, indicating the number of carbons in these simple sugars.

• Two key trioses: Glyceraldehyde and dihydroxyacetone are the two principal trioses that play substantial roles in cellular metabolism.
• In glycolysis: Both of these trioses are intermediates in glycolysis, the pathway through which glucose is broken down to produce energy.
• Biological significance: Trioses participate in pathways related to energy generation and are precursors for more complex molecules.

Even though trioses are not as abundant in nature as pentoses or hexoses, their role in metabolic pathways signifies their importance in metabolic applications.