Chromophores
• They are groups with one element of unsaturation (unsaturated linkages or groups) and cause coloring to the molecules when they are attached to a non-absorbing hydrocarbon chain.


Auxochromes
• They are groups that do not confer color but increase the coloring power of a chromophore.
• They are functional groups that have non-bonded valence electrons and show no absorption at l > 220 nm; they absorb in the far UV.
• -OH and -NH2 groups cause a red shift.

MCQs on CARBOHYDRATES AND CARBOHYDRATE METABOLISM ⇩

MCQ. No.95 Carbohydrates..

Explanation:

In the presence of low blood glucose, epi- nephrine or norepinephrine interacts with specific receptors to stimulate adenylate cyclase production of cyclic AMP. Cyclic AMP activates protein kinase, which catalyzes phosphorylation and activation of phosphorylase kinase. Activated phosphorylase kinase activates glycogen phosphorylase, which catalyzes the breakdown of glycogen. Phosphorylase kinase can be activated in two ways. Phosphorylation leads to complete activation of phosphorylase kinase.
Alternatively, in muscle, the transient increases in levels of Ca++ associated with contraction lead to a partial activation of phosphorylase kinase. Ca++ binds to calmodulin, which is a subunit of phosphorylase kinase. Calmodulin regulates many enzymes in mammalian cells through Ca++ binding.