Most tumors induce the formation of new blood vessels that invade the tumor and nourish it, a process called angiogenesis. Following statements are regarding to angiogenesis.

A. Angiogenesis allow the tumor to increase in size and thus increase the probability that additional harmful mutations will occur.

B. Angiogenesis also facilitates the process of metastasis.

C. The VEGF receptors, which are tyrosine kinases, regulate several aspects of angiogenesis such as endothelial cell survival and growth, endothelial cell migration, and vessel wall permeability.

D. VEGF expression can be induced by oncogenes and by hypoxia, defined as a partial pressure of oxygen of more than 7 mmHg.

E. A transcription factor VEGF is activated in low-oxygen conditions and which binds to and induces transcription of the HIF-1 gene which  affect the probability of tumor growth by angiogenesis.

Which of the following statements are incorrect?

#Question id: 4112

#Unit 3. Fundamental Processes

Which of the following is the structure of the nucleotide at the branch site of a spliced intron?

#Question id: 4113

#Unit 3. Fundamental Processes

Match the transcriptional machinery with their respective RNA Polymerase

#Question id: 4114

#Unit 3. Fundamental Processes

Splice-site recognition is prone to two kinds of errors. First, splice sites can be skipped, with components bound at, for example, a given 5’ splice site pairing with those at a 3’ site beyond the correct one. Ways in which the accuracy of splice-site selection can be enhanced are as

A. The factors that recognize that site are transferred from the polymerase carboxy-terminal “tail” onto the RNA. Once in place, the 5’ splice site components are poised to interact with those other factors that bind to the next 3’ splice site to be synthesized.

B. SR (serine–arginine-rich) proteins bind to sequences called exonic splicing enhancers (ESEs) within the exons. SR proteins bound to these sites recruit the splicing machinery to the nearby splice sites to ensure correct splicing

C. By recruiting splicing factors to each side of a given exon, this process encourages the so-called “exon definition, contribute to correct splicing

D. Alternative splicing is intentional missplicing mechanism

Which of the following is INCORRECT?

#Question id: 4115

#Unit 3. Fundamental Processes

The possible type of splicing outcome of given gene construct will be

#Question id: 4116

#Unit 3. Fundamental Processes

Proteins that regulate splicing bind to specific sites called exonic (or intronic) splicing enhancers (ESE or ISE) or silencers (ESS and ISS). The former enhances, and the latter repress, splicing at nearby splice sites. Examples of splicing activator and repressors are as

#Question id: 4117

#Unit 3. Fundamental Processes

The RNA recognition motif (RRM), also called the RNP motif and the RNA-binding domain (RBD), is the most common RNA-binding domain in hnRNP proteins. Choose important characteristics of RBD

a. RRM domain consists of a four-stranded b sheet flanked on one side by two a helices.

b. To interact with the negatively charged RNA phosphates, the b sheet forms a positively charged surface

c. The 45-residue KH motif is also found in the hnRNP and several other RNA-binding proteins

Which of the following statements are correct?