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?

#Question id: 2073

#Unit 2. Cellular Organization

The phosphate transport system in bacteria imports phosphate into the cell even when the concentration of phosphate outside the cell is much lower than the cytoplasmic phosphate concentration. Phosphate import depends on a pH gradient across the membrane—more acidic outside the cell than inside the cell. In this bacterial cell, phosphate transport is an example of:

#Question id: 9605

#Unit 9. Diversity of Life Forms

A phylogenetic tree that is ʺrootedʺ is one

#Question id: 2515

#Unit 2. Cellular Organization

Which of the following cell types would be the best source of actin?

#Question id: 8713

#Unit 9. Diversity of Life Forms

Which statement represents the best explanation for the observation that the nuclear DNA of wolves and domestic dogs has a very high degree of sequence homology? Dogs and wolves ________.

#Question id: 7189

#Unit 5. Developmental Biology

Following statements were made regarding vulval development in C. elegans:

A. The formation of the anchor cell is mediated by lin-12, the C. elegans homologue of the Notch gene.

B. The formation of the anchor cell is mediated by lin-12, the C. elegans homologue of the Delta gene.

C. The lin-12 gene needs to function only in that cell destined to become the uterine precursor cell.

D. Presumptive Anchor cell also need lin-12.

E. Two cells originally synthesize both the signal for uterine differentiation (the LAG-2 protein, homologous to Delta) and the receptor for this molecule (the LIN-12 protein, homologous to Notch.

Which one of the following options represents a combination of correct statements?