Following statements are regarding to maternally provided mRNAs—hunchback and caudal, are critical for patterning the anterior and posterior regions of the body plan, respectively.

A. These two mRNAs are synthesized by the nurse cells of the ovary and transported to the oocyte, where they are distributed ubiquitously throughout the syncytial blastoderm.

B. Translation of the hunchback and caudal mRNAs is repressed by the diffusion gradients of Bicoid and Nanos proteins, respectively.

C. Bicoid binds to a specific region of caudal’s 3′UTR. Here, it binds Bin3, a protein that stabilizes an inhibitory complex that prevents the binding of the mRNA 5′ cap to the ribosome. By recruiting this translational inhibitor, Bicoid prevents translation of caudal in the anterior of the embryo.

D. Nanos protein prevents translation of the hunchback message. Nanos in the posterior of the embryo forms a complex with several other ubiquitous proteins, including Pumilio and Brat. This complex binds to the 3′UTR of the hunchback message, where it recruits d4EHP and prevents the hunchback message from attaching to ribosomes.

Which of the following statements are true?

#Question id: 10790

#Unit 6. System Physiology – Plant

chalcone synthase (CHS) involved in biosynthesis of phenolic compound in plants. Following are some statements regarding the action of CHS;

 a) Chalcone synthase catalyzes the conversion of p-Coumaroyl-CoA into Chalcones

 b) Substrate for Chalcone synthase is chalcone

 c) CHS activity increased by environmental factors, such as light, and fungal infection

 d) Chalcone synthase is enzyme in flavonoid biosynthesis catalyzes stepwise condensation into p-Coumaric acid by using Malonyl-CoA molecules

 Which of the following combinations of above statement is true?

#Question id: 10791

#Unit 6. System Physiology – Plant

Following are certain statements regarding furanocoumarins;

 a) furanocoumarins have an attached furan ring

 b) These compounds are toxic until they are activated by sunlight in the ultraviolet A (UV-A) region (320–400 nm)  

 c) Light activated furanocoumarins can insert themselves into the double helix of DNA and bind to the pyrimidine bases, thus blocking transcription and repair and leading eventually to cell death   

 d) Phototoxic furanocoumarins are especially abundant in members of the Umbelliferae family, including celery, parsnip, and parsley.

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

#Question id: 10792

#Unit 6. System Physiology – Plant

Compounds such as caffeic acid and ferulic acid occur in soil in appreciable amounts and have been shown,

#Question id: 10793

#Unit 6. System Physiology – Plant

Hydroxyl groups (−OH),  and methoxy groups(−OCH3) modification provides colour variations in case of

#Question id: 10794

#Unit 6. System Physiology – Plant

Which one of the following characteristics of about lignin is incorrect?

#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: