Following statements are regarding to the wnt signalling.

A. Wnt proteins interact with several cell-surface proteins and activate multiple downstream signal transduction pathways. The principal signaling receptor for Wnt proteins is Frizzled (Fz), which contains seven transmembrane α helices.

B. The palmitate attached to the Wnt protein binds to a specific site on the Fz intracellular domain and stabilizes the Wnt-Fz complex.

C. “canonical” Wnt signaling pathway uses a second transmembrane protein, LRP, that associates with Frizzled in a Wnt signal– dependent manner.

D. In the resting state, two kinases in the complex, casein kinase 1 (CK1) and GSK3, sequentially phosphorylate β-catenin on multiple tyrosine residues.

Which of the following statements are correct?

TLS Online TPP Program

#Question id: 15781

#Unit 5. Developmental Biology

Chemical regulation of stem cells takes the form of secreted proteins from surrounding cells that influence stem cell states and progenitor differentiation through endocrine, paracrine, or juxtacrine mechanisms. These signaling factors:

TLS Online TPP Program

#Question id: 15780

#Unit 5. Developmental Biology

In drosophila, the somatic cells of the hub are able to regulate stem cell proliferation by secreting the paracrine factor Unpaired onto the cells attached to them. Unpaired activates the JAK-STAT pathway in the adjacent germ stem cells to specify their self-renewal. Those cells that are distant from the paracrine factor cannot receive this signal, they begin their differentiation into the sperm cell lineage. This means hub cells act as

TLS Online TPP Program

#Question id: 15779

#Unit 5. Developmental Biology

During stem cell regulation extracellular mechanisms leading to intracellular changes that regulate stem cell behaviour. Which of the following is not consider as extracellular mechanisms for stem cell regulation?

TLS Online TPP Program

#Question id: 15778

#Unit 5. Developmental Biology

Stem cell regulation is highly influenced by the microenvironment that surrounds a stem cell and is known as the

TLS Online TPP Program

#Question id: 15777

#Unit 5. Developmental Biology

Which of the following is not a property of the progenitor cell?

TLS Online TPP Program

#Question id: 15776

#Unit 5. Developmental Biology

Which stem cells play critical roles in fueling organogenesis in the embryo and regeneration in adult tissues?

A. Adult stem cells.

B. Embryonic stem cells

C. True stem cells

D. Tissue specific stem cells