Which of the following statement is true regarding second level of organization 

a. The second level of organization is the coiling of the 10-nm fiber of nucleosomes into a helical array.

b. The coiled helical array to constitute the fiber of diameter 30 nm that is found in interphase chromatin and in mitotic chromosomes.

c. This compacts the DNA - 40-fold. The structure of this fiber requires the histone tails and is stabilized by linker histones.

d. Histone H1, histone tails, and increased ionic strength all promote the formation of the 30-nm fiber.

#Question id: 4078

#Unit 3. Fundamental Processes

Which of the following is (are) required for splicing to occur?

a. two transesterification reactions

b. intact, naturally occurring introns

c. formation of a lariat like structure

d. a branch-point G residue

#Question id: 4079

#Unit 3. Fundamental Processes

What is the evidence that pre-mRNAs are not synthesized unless machinery for processing is properly positioned?

#Question id: 4080

#Unit 3. Fundamental Processes

How the location of exons and introns within a gene are determined?

#Question id: 4081

#Unit 3. Fundamental Processes

Which of the following regulatory scenarios of cell-type-specific expression of fibronectin isoforms in humans is (are) consistent with information on known splicing factors?

a. A Tra-like splicing factor expressed in fibroblasts is required for inclusion of EIIIA and EIIIB exons.

b. An Sxl-like splicing factor is required in hepatocytes for exclusion of EIIIA and EIIIB exons.

c. A Tra-2-like factor enhances binding of the cleavage/polyadenylation complex in fibroblasts.

d. A Dsx-like protein is required to inhibit transcription of the fibronectin gene.

#Question id: 4082

#Unit 3. Fundamental Processes

Which of the following is (are) not involved in alternative splicing in eukaryotes?

#Question id: 4083

#Unit 3. Fundamental Processes

Differential splicing of the Ca2+-activated K+ channel gene in ciliated neurons results in

a. hair cells with different response frequencies.

b. different channel isoforms.

c. channels that open at different calcium concentrations.

d. different channel mRNAs expressed in different cells.