Following statements are regarding to the desensitization mechanism of GPCR.

A. Several residues in the cytosolic domain of the β-adrenergic receptor are phosphorylated by the enzyme rhodopsin kinase.

B. β-Arrestin binds to specific phosphorylated tyrosine residues in the C-terminal segment of G protein–coupled receptors (GPCRs).

C. Clathrin and AP2, two other proteins bound by β-arrestin, promote endocytosis of the receptor.

D. β-Arrestin also functions in transducing signals from activated receptors by binding to and activating several cytosolic protein kinases like Src activates the MAP kinase pathway, leading to phosphorylation of key transcription factor.

Which of the following combination is incorrect?

#Question id: 11276

#Unit 10. Ecological Principles

Following statement regarding efficiency at different tropic level for secondary production?

A-high production efficiency individual able to survive at little food

B-production efficiency decrease toward increase tropic level 

C-aquatic herbivore is more efficient grazer than terrestrial grazer

D- Carnivore assimilation efficiency appear to average around 10%

Which above combination are correct?

#Question id: 11277

#Unit 10. Ecological Principles

If a species is a keystone predator, then its removal from a community should

(A) Increase population size of the predator’s preferred prey

(B) decrease species diversity in the prey community

(C) decrease productivity of the predator’s preferred prey

(D) increase species diversity in the prey community

#Question id: 11278

#Unit 10. Ecological Principles

Which of the following is true with respect to oligotrophic lakes and eutrophic lakes?

A) Oligotrophic lakes are less subject to oxygen depletion.

B) Rates of photosynthesis are lower in eutrophic lakes.

C) Eutrophic lake water contains higher concentrations of nutrients.

D)Sediments in oligotrophic lakes contain larger amounts of decomposable organic matter.

#Question id: 11279

#Unit 10. Ecological Principles

Ecosystem A: Actual link 10, number of species 15  

Ecosystem B: Actual link 10, number of species 20   

Connectance of ecosystem A and B

#Question id: 11280

#Unit 10. Ecological Principles

Ecosystem services include processes that increase the quality of the abiotic environment. Which of the following processes would fall under this category?

#Question id: 11281

#Unit 10. Ecological Principles

Owls eat rats, mice, shrews, and small birds. Assume that, over a period of time, an owl consumes 5,000 J of animal material. The owl loses 2,300 J in feces and owl pellets and uses 2,500 J for cellular respiration. What is the production efficiency of this owl?