There is a growing body of evidence that acetylation of histone N-termini in specific chromosomal regions contributes to gene control by regulating the binding of histones to DNA and regulation of the folding state of chromatin. The extent of histone acetylation is correlated with the relative resistance of chromatin DNA to digestion by nucleases. Which combination of histone acetylation state and DNAse 1 resistance is characteristic of actively transcribed regions of chromatin?

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#Question id: 12201

#Unit 6. System Physiology – Plant

ARF dependent signalling are regulated by auxin concenteration, given some condition followed;

I) In the absence of auxin

 II) In the presence of auxin

Find the statements that are correctly matched with given certain condition,

a)  AUX/IAA repressor proteins containing interaction domains similar to those found in the ARFs form heterodimers with the ARFs and thus repress transcriptional activation

b)  AUX/IAA repressors are recruited to the TIR1/AFB receptor complex and are tagged with ubiquitin for degradation by the 26S proteasome

c) ARFs form homodimers via conserved interaction domains and recruit chromatin remodelling

Which of the following combination is correct?

TLS Online TPP Program

#Question id: 12202

#Unit 6. System Physiology – Plant

Auxin-responsive genes typically have

TLS Online TPP Program

#Question id: 12203

#Unit 6. System Physiology – Plant

Which factor function as auxin co-receptors, with auxin acting as a “molecular glue”?

TLS Online TPP Program

#Question id: 12204

#Unit 6. System Physiology – Plant

Feedback regulation represents another key mechanism employed to attenuate a response such as

a) AUX/IAA proteins can bind to the promoters of their own genes and repress their own expression

b) auxin signaling triggers the degradation of AUX/IAA repressors, the ensuing transcription of auxin response genes leads to the replacement of AUX/IAA proteins and thus to response attenuation or termination

c) AUX/IAA genes, which encode the AUX/IAA auxin repressor proteins, have auxin response element binding sites located in their promoter regions

During the feedback regulation mechanism of auxin several responses are trigger, find out the correct sequences of these responses.

TLS Online TPP Program

#Question id: 12391

#Unit 6. System Physiology – Plant

Which of the following processed are involve in cell enlargement in plant?

a) Osmotic uptake of water across the plasma membrane is driven by the gradient in water potential (∆Yw)

b) Turgor pressure builds up because of the rigidity of the cell wall

c) Biochemical wall loosening occurs, allowing the cell to expand in response to turgor pressure

TLS Online TPP Program

#Question id: 12392

#Unit 6. System Physiology – Plant

 According to the acid growth hypothesis, the source of the hydrogen ions is the plasma membrane H+-ATPase, whose activity is thought to increase in response to