There are at least three different types of companion cells in the minor veins of mature, exporting leaves. Which of the following statements about these companion cells is CORRECT?

 a.) transfer cells are transport sugars enter the apoplast during the movement of sugars from mesophyll cells to sieve elements. Transfer cells transport sugars from the apoplast to the symplast of the sieve elements and companion cells in the source.

 b.) the numerous mitochondria in companion cells may supply energy as ATP to the sieve elements

 c.) Ordinary companion cells can function in either symplastic or apoplastic short-distance transport in source leaves, depending in part on plasmodesmatal frequencies

 d.) Intermediary cells, by contrast, function in symplastic transport of sugars from mesophyll cells to sieve elements

TLS Online TPP Program

#Question id: 30111

#Unit 1. Molecules and their Interaction Relevant to Biology

What is the source of the C-2 during the de novo biosynthesis of pyrimidines?

TLS Online TPP Program

#Question id: 30112

#Unit 1. Molecules and their Interaction Relevant to Biology

With respect to the de novo synthesis of nucleotides, which one of the following statements is INCORRECT?

TLS Online TPP Program

#Question id: 30113

#Unit 1. Molecules and their Interaction Relevant to Biology

Aspartate (Asp) is an amino acid with the structure NH2-CH(CH2-COOH)COOH. Given below are biosynthetic processes occurring in cells:

A. protein synthesis

B. de novo synthesis of inosine monophosphate and orotic acid

C. synthesis of adenosine monophosphate from inosine monophosphate

D. glutathione synthesis

Which one of the following options correctly represents all the biosynthetic process( es) wherein Asp is involved as a precursor?

TLS Online TPP Program

#Question id: 30114

#Unit 1. Molecules and their Interaction Relevant to Biology

In the case of monoclonal antibody production by hybridoma technology, myeloma cells used lack the enzyme hypxanthine - guanine phosphoriboxyl transferase(HGPRT) such that fused cells can only survive when selected on hypoxanthine-aminopterinthymdine (HAT). What is the role of aminopterin in this medium?

TLS Online TPP Program

#Question id: 30115

#Unit 1. Molecules and their Interaction Relevant to Biology

The antibacterial trimethoprim is an inhibitor of 

TLS Online TPP Program

#Question id: 30115

#Unit 1. Molecules and their Interaction Relevant to Biology

The antibacterial trimethoprim is an inhibitor of