Brassinosteroids are synthesized from the plant sterol campesterol, which is similar in structure to cholesterol. Members of the cytochrome P450 monooxygenase (CYP) enzyme family that are associated with the ER catalyze most of the reactions in the brassinosteroid biosynthesis pathway.

Mevalonic acid serves as a precursor of the triterpenoid pathway and is condensed and transformed to 2,3-oxidosqualene which further undergoes modification to form major plant sterols like sitosterols and campesterols.

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#Unit 1. Molecules and their Interaction Relevant to Biology

His ionisation series

1------pK1-----pKr--------pKr------14

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#Unit 1. Molecules and their Interaction Relevant to Biology

Glycine at pH 2.34, where there is an equal mixture of

  the average or net positive charge is 0.5 or +1/2

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#Unit 1. Molecules and their Interaction Relevant to Biology

TLS Online TPP Program

#Id: 8041

#Unit 1. Molecules and their Interaction Relevant to Biology

There are two type representation of amino acid structure

1. By Fischer’s convention L and D

2. By absolute configuration RS System

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#Unit 1. Molecules and their Interaction Relevant to Biology

A system to unambiguously describe the configurations of molecules with more than one asymmetric center was devised in 1956 by Robert Cahn, Christopher Ingold, and Vladimir Prelog. In the Cahn–Ingold– Prelog or RS system

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#Id: 8043

#Unit 1. Molecules and their Interaction Relevant to Biology

RS Configuration 

Atoms of higher atomic number rank above those of lower atomic number (e.g., —OH ranks above —CH3). If the first substituent atoms are identical, the priority is established by the next atom outward from the chiral center (e.g., —CH2OH takes precedence over —CH3).