31.

Which of the following statements is INCORRECT in relation to the treatment of pre-B cells with phorbol esters?

• Phorbol esters activate NFxB for translocation into the nucleus.

• Phorbol esters activate protein kinase C.

• Phorbol esters lead to phosphorylation of NF × B.

• Phorbol esters remove the inhibitor from inactive NFxB complex in the cytoplasm

Presence of an internal ribosome entry site (IRES) in mRNA

• Inhibits its translation.

• Promotes its post-transcriptional processing.

• Has no impact on its translation.

• Promotes its translation under adverse conditions    

Regulatory elements for expression of ribosomal RNA genes reside in the

• Transcribed spacer region

• Non-transcribed spacer region    

• 5’ flanking region of individual ribosomal RNA genes.

• Internal regions within the genes.

Mycobacterium tuberculosis is an intracellular bacterium. It prefers to infect

• Macrophages

• B-cells

• T-cells

• Neutrophils

Integrin molecules link extracellular matrix (ECM) to the actin cytoskeleton of cells. Integrin binds to which of the following ECM macromolecules?

• Laminin

• Collagen

• Fibronectin

• Vitronectin

CD19 is a marker for

• B-cells

• T-cells

• Macrophages

• NK cells

Given below are fate maps of two organisms and the patterns by which embryos undergo cleavage. Which of the following is/ are the right combination (s)?

• B only

• B and A

• A and C

• B and D

Which one of the following matches of oncogene-protein product is NOT correct?

• erbA- thyroid hormone receptor

• erbB- epidermal growth factor receptor

• ras- guanine nucleotide-binding protein with GTPase  activity

• fos  - platelet-derived growth factor receptor.        

Spematogonial stem cell undergoes extensive metamorphosis to become a spermatozoan. Meiosis leads to the formation of spermatids containing 22 autosomes and one sex chromosome. A male mouse was found in a colony which always produces only female pups upon mating. Which one of the following is a possible reason?

• Spermiogenesis was defective.

• All spermatogonial stem cells contained only X and no Y chromosome.

• Activation of the Y chromosome-linked post-meiotic death-related gene may lead to such a situation.   

• Activation of the X chromosome-linked post-meiotic death-related gene may lead to such a situation.

In the case of Xenopus laevis, which cells make up the Nieuwkoop center and Spemann’s organizer?

• Endodermal and mesodermal, respectively   

• Mesodermal and endodermal, respectively

• Endodermal and ectodermal, respectively

• Ectodermal and endodermal, respectively