#Question id: 4644
#Unit 11. Evolution and Behavior
The treeʹs horizontal axis is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (V—Z) represent various common ancestors. Letʹs say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species.
According to this tree, what percent of the species seem to be extant (i.e., not extinct)?
#Question id: 31360
#Unit 3. Fundamental Processes
#Question id: 4098
#Unit 3. Fundamental Processes
A merodiploid with a mutant repressor gene (Is) is shown below. The mutant repressor therefore binds irreversibly to both operators and will render
#Question id: 28840
#Unit 2. Cellular Organization
Which of the following 8-subunit protein complex that binds to sites along the microtubule and recruits γ-TuRC, which nucleates a new microtubule to form a microtubule branch?
#Question id: 2578
#Unit 2. Cellular Organization
Following statements are regarding to proteins which involve actin filament assembly.
A. To nucleate the assembly of branched actin, Arp2/3 needs to be activated by interacting with a nucleation promoting factor (NPF), in addition to associating with the side of a pre-existing actin filament.
B. The NPF WASp is inactive due to an intramolecular interaction that masks the WCA domain.
C. Two NPFs each bind an actin subunit at their WH2 domains, and together, they activate the Arp2/3 complex through its interaction with their connector and acidic domains.
D. The NPF WASp is activated by a coincidence detection mechanism by which intramolecular interaction in WASp is relieved, allowing the W domain to bind actin and the acidic A domain to activate the Arp2/3 complex.
Which of the following statements represents regulation of the Arp2/3 complex by NPF?