When the temperature of a solution of DNA is raised to near the boiling point of water, the optical density, (called absorbance) at 260 nm markedly increases, a phenomenon known as hyperchromicity. Which of the following properties gets changed due to subsequent denaturation of the DNA molecule?

#Question id: 10795

#Unit 6. System Physiology – Plant

basic carbon skeleton of a flavonoid contains 15 carbons arranged in two aromatic rings connected by a three-carbon bridge. This structure results from two separate biosynthetic pathways:

#Question id: 10796

#Unit 6. System Physiology – Plant

Flavonoids are one of the largest classes of plant phenolics, structure of flavonoids;

#Question id: 10797

#Unit 6. System Physiology – Plant

The colored pigments of plants are of two principal types: carotenoids and flavonoids. Given below some statements of about these pigments;

 a) Anthocyanins are colored flavonoids that attract animals

b) Flavonoids are phenolic compounds that include a wide range of colored substances

c) Carotenoids are coloured terpenoid compounds that also serve as accessory pigments in photosynthesis

d) most widespread group of pigmented carotenoids is the anthocyanins, these are glycosides that have sugars. Without their sugars, anthocyanins are known as anthocyanidins

Which of the following is incorrect statements of these pigments;

#Question id: 10798

#Unit 6. System Physiology – Plant

Two other major groups of flavonoids found in flowers and leaves of all green plants. The function of these two flavonoids in plants are____

a) protect plants against being eaten by herbivores and against being infected by microbial pathogens

b) Protect cells from excessive UV-B radiation (280–320 nm) because they accumulate in the epidermal layers of leaves and stems and absorb light strongly in the UV-B region       

c) flavones and flavonols secreted into the soil by legume roots mediate the interaction of legumes and nitrogen-fixing symbionts

d) They are are coloured terpenoid compounds that also serve as accessory pigments in photosynthesis    

Which of the following combination from the above statements is correct?

#Question id: 10799

#Unit 6. System Physiology – Plant

Arabidopsis thaliana mutants that lack the enzyme chalcone synthase____

#Question id: 10800

#Unit 6. System Physiology – Plant

Which of the following secondary metabolites causes infertility in the