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TLS Online TPP Program

#Question id: 13163

Following statements are regarding to the interaction between β2-adrenergic receptor and G- protein.

#Unit 4. Cell Communication and Cell Signaling
  1. Binding of ligand to the receptor induces major conformational changes in which there are substantial movements of transmembrane helices 5 and 6 and changes in the structure of the C3 loop; together, these changes create a surface that can bind to a segment of the Gα subunit and when unbound by ligand, the receptor has no surface that is complementary to the G protein and thus cannot bind to it.
  2. Binding of ligand to the receptor induces major conformational changes in which there are substantial movements of transmembrane helices 1 and 4 and changes in the structure of the C3 loop; together, these changes create a surface that can bind to a segment of the Gα subunit and when unbound by ligand, the receptor has no surface that is complementary to the G protein and thus cannot bind to it.
  3. Binding of ligand to the receptor induces major conformational changes in which there are substantial movements of transmembrane helices 5 and 6 and changes in the structure of the C3 loop; together, these changes have no surface that can’t bind to a segment of the Gα subunit and when unbound by ligand, the receptor creates a surface that is complementary to the G protein and thus can bind to it.
  4. Binding of ligand to the receptor induces major conformational changes in which there are substantial movements of transmembrane helices 3, 5, 6 and 7 and changes in the structure of the E2 loop; together, these changes create a surface that can bind to a segment of the Gα subunit and when unbound by ligand, the receptor has no surface that is complementary to the G protein and thus cannot bind to it.
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TLS Online TPP Program

#Question id: 11826

#Unit 6. System Physiology – Plant

Some given statements about ethylene signalling pathways are listed;

a) Ethylene receptors are interact with two downstream signaling proteins, CTR1 (CONSTITUTIVE TRIPLE RESPONSE1) and EIN3 (ETHYLENE-INSENSITIVE3)

b) CTR1 is a soluble serine/threonine kinase that is associated with ethylene receptors, while EIN2 is an ER transmembrane protein with a cytosolic C-terminal domain that is a target for CTR1 kinase activity

c) EIN2 is required to stabilize transcription factors of the EIN3 (ETHYLENEINSENSITIVE3) family, which activate the transcription of ethylene-responsive genes

d) EIN3 is required to stabilize transcription factors of the EIN2 (ETHYLENEINSENSITIVE2) family, which activate the transcription of ethylene-responsive genes

Which of the following is the correct statements  of auxin signalling pathway ?
TLS Online TPP Program

#Question id: 11827

#Unit 6. System Physiology – Plant

Which of the following enzyme is involved in the rate-limiting step in ethylene biosynthesis?
TLS Online TPP Program

#Question id: 11828

#Unit 6. System Physiology – Plant

Given some enzymes of ethylene biosynthetic pathway and its character;

A) ACC synthase                                                               i) It is an unstable, cytosolic enzyme. Its level is regulated by environmental and internal factors, such as wounding, drought stress, flooding, and auxin

B) ACC oxidase                                                                  ii) It catalyzes the last step in ethylene biosynthesis, the conversion of ACC to ethylene

                                                                                                iii) Its activity can be the rate-limiting step in ethylene biosynthesis

                                                                                                iv) That is encoded by a multigene family that is differentially regulated

                                                                                                v) It is present in such low amounts in plant tissues and is very unstable and also difficult to purify the enzyme  for biochemical analysis

                                                                                                vi) These enzymes belong to the Fe2+/ascorbate oxidase superfamily

Find out the correct combination from the given enzymes and its character?
TLS Online TPP Program

#Question id: 11829

#Unit 6. System Physiology – Plant

The certain cyclic olefin compounds, have been shown to block ethylene breakdown without inhibiting ethylene action?
TLS Online TPP Program

#Question id: 11830

#Unit 6. System Physiology – Plant

Not all the ACC found in the tissue is converted to ethylene, ACC can also be converted to a conjugated form, which does not appear to break down and accumulates in the tissue?
TLS Online TPP Program

#Question id: 11831

#Unit 6. System Physiology – Plant

A volatile compound is a strong competitive inhibitor of ethylene binding______