The regeneration blastema forms from pluripotent stem cells called clonogenic neoblast. If cNeoblasts are essential for regeneration, their total loss should prevent regeneration. Following statements are made in respect to planaria regeneration are given below.

(A) The gene sigma/zeta is expressed by all neoblasts and has become the most common marker for their identification across planarian species.

(B)   In planaria, Wnt/β-catenin functions to establish dorsal ventral polarity of the regenerating flatworm.

(C)   Inhibition of Wnt/β-catenin signaling in regeneration-deficient species yields fully functional regenerated heads.

(D)   If β-catenin is eliminated from the posterior (tail-forming) blastema by RNA interference, that blastema will form a tail.

Which of the above statements are true?

#Question id: 2808

#Unit 2. Cellular Organization

A microsatellite is a type of polymorphism that

a. results from the change of a single nucleotide.

b. changes the recognition sequence for a restriction enzyme.

c. results from a variable number of repetitive sequences.

d. results from a chromosomal inversion.

#Question id: 2809

#Unit 2. Cellular Organization

In the human genome, one centimorgan or a 1 percent recombination frequency represents, on average, a distance of about

#Question id: 2810

#Unit 2. Cellular Organization

Which of the following steps is required to generate a knockout mouse?

a. microinjection of DNA into the pronucleus of a fertilized mouse egg

b. introduction of DNA into mouse embryonic stem cells

c. selection for cells containing the gene targeted insertion

d. expression of Cre protein during embryonic development

#Question id: 2811

#Unit 2. Cellular Organization

RNA interference is a method for inhibiting the function of specific genes using

a. single-stranded DNA.                     

b. double-stranded DNA.

c. single-stranded RNA.                     

d. double-stranded RNA.

#Question id: 2812

#Unit 2. Cellular Organization

Which of the following statements is (are) true of the human genome?

a. 1.5 percent of the genome corresponds to protein coding sequences.

b. The median length of an intron is 10 kb.

c. 10 percent of the genome is transcribed into pre mRNA precursors.

d. Most human exons contain 500–1000 base pairs.

#Question id: 2813

#Unit 2. Cellular Organization

DNA fingerprinting is a technique based on differences in the

a. length of introns.   

 b. number of tandem copies of a simple sequence repeat.

c. number of tandem ribosomal RNA genes.

d. size of protein coding genes.