Which of the following process is critical for the polarized, directed growth of the actin network that is responsible for unidirectional cell crawling and the intracellular motility of pathogens?

#Question id: 732

#Unit 1. Molecules and their Interaction Relevant to Biology

Ramachandran plots can help increase the accuracy of models derived from x-ray crystallography data. The plot below was created by measuring phi, and psi for each amino acid residue in a 2.2 A resolution crystal structure. In the plot, which excludes Gly and Pro residues, selected residues (dots) are numbered 1 through 5.

Which of the following statements can be correctly stated for this plot in reference to selected residues?

A. Residues 1 and 3 are in either B sheets

B. residue 2 is in a right-handed a helix, and residue 4 is in a left-handed a helix.

C. If residue 5 were Gly, it might be in an acceptable position in the plot

#Question id: 2037

#Unit 4. Cell Communication and Cell Signaling

Which of the following complement receptor activate a humoral response by promoting trapping of an antigen-antibody complex?

#Question id: 2605

#Unit 2. Cellular Organization

The precursor of trp is;

#Question id: 12115

#Unit 10. Ecological Principles

#Question id: 12228

#Unit 10. Ecological Principles