D-glucose, also known as dextrose and blood sugar, is the most abundant monosaccharide in nature and plays a crucial role as a primary source of energy for cells.
Carbohydrates are classified as monosaccharides, disaccharides, oligosaccharides, and polysaccharides based on their molecular size. The general formula for carbohydrates is CnH2nOn or Cn(H2O)n.
The five important reactions of monosaccharides are oxidation to acidic sugars, reduction to sugar alcohols, glycoside formation, phosphate ester formation, and amino sugar formation.
Biochemistry is the study of the chemical substances found in living organisms and the chemical interactions of these substances with each other.
D-galactose and D-glucose are classified as epimers, which are diastereomers that differ only in the configuration at one chiral center.
Green plants produce carbohydrates via photosynthesis, using carbon dioxide from the air and water from the soil as reactants, with sunlight as the energy source.
In human body chemistry, right-handed and left-handed forms of a molecule often elicit different responses within the body. Enantiomers are stereoisomers that are nonsuperimposable mirror images of each other, while diastereomers are stereoisomers that are not mirror images of each other.
The normal concentration of glucose in human blood is in the range of 70 – 100 mg/dL. After eating, glucose concentration can rise to about 130 mg/dL in the first hour, then decreases over the next 2 – 3 hours back to the normal range.
Monosaccharides are carbohydrates that contain a single polyhydroxy aldehyde or polyhydroxy ketone unit and cannot be broken down into simpler units by hydrolysis reactions. Disaccharides contain two monosaccharide units covalently bonded to each other, while polysaccharides are polymeric carbohydrates that contain many monosaccharide units covalently bonded to each other, with the number of units varying from a few hundred to more than a million.
The two stereoisomers produced during cyclic monosaccharide formation are called anomers. The α-stereoisomer has the —OH group on the opposite side of the ring from the —CH2OH group, while the β-stereoisomer has the —OH group on the same side as the —CH2OH group.
Chirality is the property of 'handedness' in molecules, where they exist in two forms: a 'left-handed' form and a 'right-handed' form. A chiral center is an atom in a molecule that has four different groups bonded to it in a tetrahedral orientation.
Carbohydrates provide energy through oxidation, serve as a short-term energy reserve in the form of glycogen, supply carbon atoms for the synthesis of other biochemical substances, form part of the structural framework of DNA and RNA, and are involved in cell recognition processes. Outside biological functions, carbohydrates are used in clothing (cotton and linen), and in the form of wood for shelter, heating, and paper making.
A reducing sugar is a carbohydrate that gives a positive test with Tollens and Benedict’s solutions.
