举一反三
- Many—if not most—protein molecules are _______: they can adopt two or more slightly different conformations, and their activity can be regulated by a shift from one to another.
- Each protein normally folds into a single stable conformation. This conformation, however, often changes dramastically when the protein interacts with other molecules in the cell.
- Which of the following signaling molecules could be directly activated by Ca ion binding? A: cAMP B: Calmodulin C: Protein kinase A D: Protein kinase B E: Protein kinase G
- Moisture in food can be divided into "bound water" and "free water" according to different properties. Which of the following is not bound water? A: The first layer of water molecules adsorbed to glucose molecules B: Water molecules with unpaired electrons entering the outer empty orbits of sodium ions C: Water molecules adsorbed in capillaries in food tissue D: Water molecules bound to the negative ion of glutamic acid on the protein peptide chain
- To synthesize one molecule of cholesterol consumes 18 molecules of acetyl-CoA.
内容
- 0
Group I introns are remarkable because: A: They are spliced by external RNA molecules without protein involvement. B: They are spliced by protein molecules in the absence of external RNA molecules. C: They are autocatalytic. D: They are only present in mitochondrial and chloroplast genomes.
- 1
How many molecules of urea can be synthesized using ATP produced from complete oxidation of one molecule of glucose? A: 7 B: 8 C: 9 D: 10
- 2
β-turns in protein molecules belong to the protein's hierarchical structure? A: Primary structure B: Secondary structure C: Tertiary structure D: Side chain conformation
- 3
Amplification results when an enzyme associated with a signal receptor is activated and, in turn, catalyzes the activation of many molecules of a second enzyme, each of which activates many molecules of a third enzyme, and so on, in a so-called _____________________.
- 4
Which of the following is NOT extracellular signaling molecules? A: Glucagon B: Epinephrine C: G protein D: Dopamine E: Angiotensin II