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1. In a plant phospho-relay system, which are thought to be derived from bacteri

ID: 257579 • Letter: 1

Question

1. In a plant phospho-relay system, which are thought to be derived from bacterial signaling cascades,

the receptor is part of the ubiquitination process (E3 ligase) targeting a repressor for degradation (proteosome)

a phosphate is passed from a sensor histidine kinase to a histdine phosphotransfer protein (Hpt) and then to a response regulator (ARR)

a protein phosphatase (PP2C) dephosphorylates a kinase domain (e.g. SnRK2) to prevent signal transduction

are not found in plants and any similarity is the result of convergent evolution

are also found in animals & involve a series of mitogen-activated protein kinases (MAPK, MAPKK, MAPKKK, etc)

2. if I want to prevent fruit from over-ripening and rotting while still in the field or during transport to market, which of the following genes / enzymes would I want to inhibit?

Isopententyl transferase

GA-20 Oxidase

yellow cameleon

ACC oxidase

brassinolide oxidase 1

3. Applying auxin exogenously to a plant may have limited effects because

auxin may form inactive conjugates with other molecules

auxin may be rapidly degraded to an inactive state

auxin may partition quickly to cellular compartments where it is not active

All of the above

Only A and C are correct

the receptor is part of the ubiquitination process (E3 ligase) targeting a repressor for degradation (proteosome)

a phosphate is passed from a sensor histidine kinase to a histdine phosphotransfer protein (Hpt) and then to a response regulator (ARR)

a protein phosphatase (PP2C) dephosphorylates a kinase domain (e.g. SnRK2) to prevent signal transduction

are not found in plants and any similarity is the result of convergent evolution

are also found in animals & involve a series of mitogen-activated protein kinases (MAPK, MAPKK, MAPKKK, etc)

2. if I want to prevent fruit from over-ripening and rotting while still in the field or during transport to market, which of the following genes / enzymes would I want to inhibit?

Isopententyl transferase

GA-20 Oxidase

yellow cameleon

ACC oxidase

brassinolide oxidase 1

3. Applying auxin exogenously to a plant may have limited effects because

auxin may form inactive conjugates with other molecules

auxin may be rapidly degraded to an inactive state

auxin may partition quickly to cellular compartments where it is not active

All of the above

Only A and C are correct

Explanation / Answer

Answer1: option-2 (phosphate is passed from a sensor histidine kinase to a histdine phosphotransfer protein (Hpt) and then to a response regulator (ARR))

Explanation: The phosphorelay signal system in plants is also called TCS (two component regulatory systems).

- Histidine (His) - protein - Kinase - activity

- Response regulators (RR) which contains a phospho accepting aspertate (Asp) residue.