Cell walls commonly are classified into two major types. This classification is based not on structural or biochemical differences;

A) primary walls and

B) secondary walls

i) walls formed during cell growth

ii) walls that are formed after cell enlargement stops

iii) multilayered walls that are strengthened and waterproofed by lignin

iv) Usually they are thin and simple, but some times may be thick and multilayered, such as those found in collenchyma or in the epidermis

v) highly specialized in structure and composition, reflecting the differentiated state of the cell

Which of the following is the correctly represents features of primary and secondary walls?

#Question id: 4489

#Unit 3. Fundamental Processes

HSP70 gene from Drosophila. This gene, activated by heat shock, is controlled by two activators GAGA binding factor and HSF,In response to heat shock, HSF binds to specific sites at the promoter and recruits a kinase, P-TEFb (positive transcription elongation factor). What is the proper mechanism of pausing and release of Pol II ?

#Question id: 4490

#Unit 3. Fundamental Processes

The human immunodeficiency virus (HIV), which causes AIDS, transcribes its genes from a promoter controlled by P-TEFb (and SEC). Again, polymerase initiates transcription at that promoter, under the control of which activator?

#Question id: 4491

#Unit 3. Fundamental Processes

HIV transcribes its genes from a promoter controlled by P-TEFb, P-TEFb is brought to the stalled polymerase by an RNA-binding protein, not a DNA-bound one. The protein responsible is called

#Question id: 4492

#Unit 3. Fundamental Processes

If an enhancer activates a specific gene 400 kb away, what stops it from activating other genes whose promoters are within that range?

#Question id: 4493

#Unit 3. Fundamental Processes

An insulator is placed between the enhancer and the promoter, When bound by insulator-binding protein CTCF,

#Question id: 4494

#Unit 3. Fundamental Processes

Propagation of certain repressing histone modifications over stretches of chromatin lies at the heart of a phenomenon is known,