Three factors are important in maintaining low O2 concentrations in nodules. 

First, entry of O2 into the nodule is controlled by a variable‐permeability barrier in the nodule parenchyma

TLS Online TPP Program

#Id: 8867

#Section 3: Genetics, Cellular and Molecular Biology

Cdc25B is act as a starter phosphatase that initiates CDK1 activation

Cdc25C is the workhorse phosphatase that activates the vast majority of cyclin-CDK1 complexes

TLS Online TPP Program

#Id: 7834

#Section 2: General Biology

TLS Online TPP Program

#Id: 7327

#Section 3: Genetics, Cellular and Molecular Biology

Loci with  multiple alleles

TLS Online TPP Program

#Id: 8886

#Section 3: Genetics, Cellular and Molecular Biology

TLS Online TPP Program

#Id: 8032

#Section 2: General Biology

Ornithine and citrulline, which are not found in proteins, are intermediates in the biosynthesis of arginine and in the urea cycle.