Which of the following is false regarding the stem cells located in the epithelium lining of the small intestine?
A. They express β-catenin.
B. Lgr5 encodes the R-spondin protein.
C. The Lgr5 gene is induced by Wnt signaling
D. They are located in pits called crypts
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Phospholipids with short or unsaturated fatty acyl chains.
A. decrease membrane fluidity
B. increase membrane fluidity.
C. cause biomembranes to become thicker
D. allow hydrophilic molecules to diffuse across the lipid bilayer
Which one of the following is the best technique/approach to allow you to localize catalase in peroxisomes?
A. a catalase monoclonal antibody and transmission electron microscopy
B. platinum or gold and scanning electron microscopy
C. FRAP and FRET
D. all of the above
The drug taxol acts to Altered (改变) function of which cytoskeletal structure or filament might cause defects in muscle contraction?
Actin filaments
B. Intermediate filaments
C. Microtubules
D. Centromes
Which of the following mutations to the Gα protein could render(致使) a G protein-coupled receptor signaling pathway constitutively active?
A. Gα cannot bind Gβγ
B. Gαcannot hydrolyze GTP
C. Gα protein cannot bind GDP
D. Gα protein cannot release GDP