Which of the following statements about G-protein-coupled receptors (GPCRs) is false?
(a) GPCRs are the largest family of cell-surface receptors in humans.
(b) GPCRs are used in endocrine, paracrine, and neuronal signaling.
(c) GPCRs are found in yeast, mice, and humans.
(d) The different classes of GPCR ligands (proteins, amino acid derivatives, or fatty acids) bind to receptors with different numbers of transmembrane domains.
(d) Although it is true that many types of ligands can bind to and activate GPCRs, all GPCRs have a similar structure with seven transmembrane domains.
You might also like to view...
Why is it not surprising that Staphylococci are the leading cause of wound infections?
A. This genus is readily present as a part of the normal microbiota on most people's skin, so it could easily enter wounds. B. Members of this genus are all particularly virulent and highly capable of causing numerous infections. C. Staphylococci cannot be eradicated from the skin due to multidrug resistance in most members of the genus. Drugs simply don't kill them. D. Staphylococci are capable of a higher degree of spontaneous mutation than most microbes. This makes them able to acquire antibiotic resistance very readily, making them hard to eliminate by pre-surgical antibacterial scrubs. As such, they commonly infect surgical wound sites.
Which of the following must be present for a cell to enter mitosis?
a. favorable environment b. high enough cell mass c. growth factor d. all of these
Respond to statements 86–90 with reference to the five plant
micronutrients listed below. a. iron b. boron c. manganese d. zinc e. copper D 86. This nutrient is needed for normal root development. D 87. This nutrient plays an important role in terminal bud formation. D 88. Deficiency of this nutrient results in chlorosis, dead spots in leaves, and stunted growth. D 89. Deficiency of this nutrient results in chlorosis and yellow, green striping in leaves of grasses. D 90. Deficiency of this nutrient results in leaves with dark veins, but leaves whiten and fall off.
In Griffith’s experiments, what made the harmless R cells grow capsules when exposed to heat-killed S cells?
a. Protein b. DNA c. Lipids d. Polysaccharides