companion cells in minor veins of mature leaves. All three cell types have dense cytoplasm and abundant mitochondria, there are three types companion cells  present in column A while its characteristics given in column B;

             COLUMN A                                                               COLUMN B

A) Ordinary companion cells             i) appear well suited for taking up solutes via cytoplasmic connections numerous plasmodesmata connecting them to bundle sheath cells. Its having numerous small vacuoles, as well as poorly developed thylakoids.

 

B) Transfer cells                                 ii) have chloroplasts with well-developed thylakoids     and a cell wall with a smooth inner surface. The number of plasmodesmata connecting ordinary companion cells to surrounding cells.

 C) Intermediary cells                          iii) the development of fingerlike wall in growths, particularly on the cell Walls. These wall ingrowths greatly increase the surface area of the transfer cell’s  plasma membrane, few plasmodesmata connect this type of companion cell to any of the surrounding cells except its own sieve element.

Which of the following correct combination;

#Question id: 793

#Unit 1. Molecules and their Interaction Relevant to Biology

What is the average size (in bp) of a mature t-RNA?

#Question id: 794

#Unit 1. Molecules and their Interaction Relevant to Biology

A single-stranded DNA molecule contains 40 nucleotides with equal amounts of A, C, G, and T. This DNA strand can combine with a complementary DNA strand to form a double-stranded DNA molecule. Which structural feature is found in the single-stranded DNA molecule?

#Question id: 795

#Unit 1. Molecules and their Interaction Relevant to Biology

A single-stranded DNA molecule contains 40 nucleotides and has the sequence 5’-(GA)20-3’. When this single strand binds to a complementary DNA strand,

#Question id: 796

#Unit 1. Molecules and their Interaction Relevant to Biology

Which statement best describes the distinction between the purposes of the two RNAi pathways within the eukaryotic cell?

#Question id: 797

#Unit 1. Molecules and their Interaction Relevant to Biology

With respect to microRNAs, which, if any, of the following statements, is FALSE?)

A. MicroRNA genes often occur in gene clusters within introns of protein-coding genes and are usually transcribed by RNA polymerase II.

B. Like an mRNA a miRNA is initially produced as a larger precursor RNA that, like the great majority of mRNAs, usually has a 5’ cap and a poly(A) tail.

C. MicroRNAs are produced by germ-line cells only.

D. A miRNA is initially produced as a duplex RNA but in order to work it needs to be converted into a single-strand RNA.

E. MicroRNAs usually work as transcription factors.

#Question id: 798

#Unit 1. Molecules and their Interaction Relevant to Biology

Match the structural properties of DNA with the respective types of DNA in which they are found.