Vitamins Save Lives
1. Explain how some vitamins act as cofactors. Begin by explaining what a cofactor is and how it influences metabolic reactions.
Cofactor is an organic/inorganic substance, which is required for an enzyme to be active and effectively carry out catalysis (Smolin and Grosvenor 308). Active vitamins (water-soluble) may act as cofactors. In this case, they are called “coenzymes”. Usually, vitamins gain their activity by binding a specific chemical group (Smolin and Grosvenor 308). After such modification, they are able to bound to a specific enzyme and activate it. Active enzyme then is ready to catalyze a reaction specific to it (Smolin and Grosvenor 308). Vitamins are important for catalyzed metabolic reactions because they carry electrons, chemical groups, or specific atoms required for the modification of a substrate by an enzyme.
2. The B vitamins’ roles in energy metabolism are often misunderstood to mean that B vitamins provide energy. How would you explain the roles of the B vitamins in metabolism while making it clear that B vitamins are not sources of energy?
Indeed, B vitamins are extremely important for energy metabolism; however, they do not act as sources of energy (Smolin and Grosvenor 308). B vitamins act as coenzymes to activate and facilitate the functioning of enzymes responsible for the production of ATP from such substances as glucose, fatty acids, and amino acids (Smolin and Grosvenor 308). Thus, in the course of metabolic reactions, B vitamins do not act as substrates for energy production, but rather provide enzymes with specific chemical groups, atoms, or electrons to modify other substances, which in the end will produce ATP. Without B vitamins, these enzymes would not be able to carry out their function, and the whole organism would experience a severe energy depletion.
3. List the differences between water- and fat-soluble vitamins including how diet influences absorption and how preparation influences availability.
The first obvious and most important difference between water- and fat-soluble vitamins is that the representatives of the first group can be dissolved only in aqueous solutions, while the members of the second group dissolve in fat (Smolin and Grosvenor 304). Because of this basic difference, other consequential ones appear. In order to be absorbed in the gastro-intestinal tract, fat-soluble vitamins require the presence of a certain amount of fat in the diet (Smolin and Grosvenor 307). Without enough fat, they will be poorly absorbed, and a fat-soluble vitamins deficiency may occur. Water-soluble vitamins require specific energy-consuming transport systems or molecules to be absorbed in the gastro-intestinal tract (Smolin and Grosvenor 307). For transportation, fat-soluble vitamins have to bind to lipoproteins or transport proteins (Smolin and Grosvenor 308). Lipoproteins and transport proteins allow fat-soluble vitamins to enter the bloodstream and reach their target cells. Water-soluble vitamins bind to blood proteins for transportation. Fat-soluble vitamins are stored in the liver and fat tissue and are not readily excreted from the body (Smolin and Grosvenor 308). Therefore, it takes a lot of time to develop a fat-soluble vitamins deficiency. On the other …
