In light reaction, the funneling of excitation from the antenna system toward the reaction centre has been shown,

a.) The excited-state energy of pigments increases with distance from the reaction centre; that is, pigments closer to the reaction centre are lower in energy than those farther from the reaction centre

b.) The energy gradient ensures that excitation transfer toward the reaction centre is energetically favorable and that excitation transfer back out to the peripheral portions of the antenna is energetically unfavourable

c.) Some energy is lost as heat to the environment by this process, but under optimal conditions almost all the excitation energy absorbed in the antenna complexes can be delivered to the reaction centre

d.) The excited-state energy of  pigments decreases with distance from the reaction centre

Which of the following above combination is true?

#Question id: 1123

#Section 3: Genetics, Cellular and Molecular Biology

Epinephrine can be what kind of signaling molecule?

a. autocrine      b. direct contact  c. endocrine d. paracrine

#Question id: 1124

#Section 3: Genetics, Cellular and Molecular Biology

Which of the following is (are) intracellular second messengers?

a. Ca2+                        b. cAMP          c. epinephrine             

d. protein kinase A      e. protein kinase C

#Question id: 1125

#Section 3: Genetics, Cellular and Molecular Biology

Examples of G protein–coupled receptors include

a. rhodopsin receptor.             b. β-adrenergic receptor.

c. insulin receptor.                   d. acetylcholine receptor.

#Question id: 1126

#Section 3: Genetics, Cellular and Molecular Biology

Which of the following statement(s) is (are) true of the α subunit of a G protein?

a. It physically associates with the receptor.              

b. It binds GDP.

c. It binds GTP.                     

d. It is a transmembrane protein.

#Question id: 1127

#Section 3: Genetics, Cellular and Molecular Biology

Which of the following steps does not occur after acetylcholine binds to the muscarinic acetylcholine receptor in heart muscle cells?

#Question id: 1128

#Section 3: Genetics, Cellular and Molecular Biology

During the epinephrine stimulated conversion of glycogen to glucose 1-phosphate, which of the following steps involves protein phosphorylation?

a. inactivation of glycogen synthase               b. activation of protein kinase A

c. activation of adenylyl cyclise                      d. activation of glycogen phosphorylase