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: 10132

#Unit 6. System Physiology – Plant

Which of the following statements would be correct for photophosphorylation ?

#Question id: 10133

#Unit 6. System Physiology – Plant

The PSI reaction center complex is a large multi-subunit complex in which the antenna chlorophylls are associated with the reaction center Components of the PSI reaction center are organized around as follows choose the incorrect one;

#Question id: 10134

#Unit 6. System Physiology – Plant

Some herbicides such as dichlorophenyldimethylurea (DCMU, also known as diuron) and paraquat, block photosynthetic electron flow from where ?

a.) DCMU blocks electron flow at the quinone acceptors of PSII, by competing for the binding site of plastoquinone that is normally occupied by PQB

b.) Paraquat accepts electrons from the early acceptors of PSI and then reacts with oxygen to form superoxide, O2 – , a species that is very damaging to chloroplast components

c.) DCMU blocks electron flow at the pheophytin acceptors of PSII, by competing for the binding site of pheophytin

d.) Paraquat accepts electrons from the Iron-sulfur system of PSI and then reacts with oxygen to form superoxide, O2 – , a species that is very damaging to chloroplast components

Which of the following combination is true?

#Question id: 10135

#Unit 6. System Physiology – Plant

Which of the following are strongest reductant?

#Question id: 10136

#Unit 6. System Physiology – Plant

A protein complex contain a Rieske protein known as

#Question id: 10137

#Unit 6. System Physiology – Plant

The Calvin–Benson cycle pathway decreases the oxidation state of carbon from the highest value, found in CO2 (+4), to levels found in sugars;  +2 in keto groups — CO—; 0 in secondary alcohols —CHOH,  In view of its notable capacity for lowering the carbon oxidation state, the Calvin–Benson cycle is also aptly named the