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TLS Online TPP Program

#Id: 9297

Nitrite reductase
Nitrite (NO2-) is a highly reactive, potentially toxic ion.
Plant cells immediately transport the nitrite into chloroplasts or plastids.
The enzyme nitrite reductase reduces nitrite to ammonium.
Leaf chloroplasts and root plastids contain different forms of nitrite reductase.
Each polypeptide contains two prosthetic groups, an iron-sulfur group and a specialized heme.
NO3-, high sucrose conc, and light induce the transcription of nitrite reductase mRNA.
Asparagine and glutamine repress the induction.

#XL - R Botany #Nitrogen Metabolism & Biological Nitrogen fixation #Part B Pointers
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TLS Online TPP Program

#Id: 9297

#XL - Q Biochemistry

Nitrite reductase
Nitrite (NO2-) is a highly reactive, potentially toxic ion.
Plant cells immediately transport the nitrite into chloroplasts or plastids.
The enzyme nitrite reductase reduces nitrite to ammonium.
Leaf chloroplasts and root plastids contain different forms of nitrite reductase.
Each polypeptide contains two prosthetic groups, an iron-sulfur group and a specialized heme.
NO3-, high sucrose conc, and light induce the transcription of nitrite reductase mRNA.
Asparagine and glutamine repress the induction.
TLS Online TPP Program

#Id: 9297

#XL - S Microbiology

Nitrite reductase
Nitrite (NO2-) is a highly reactive, potentially toxic ion.
Plant cells immediately transport the nitrite into chloroplasts or plastids.
The enzyme nitrite reductase reduces nitrite to ammonium.
Leaf chloroplasts and root plastids contain different forms of nitrite reductase.
Each polypeptide contains two prosthetic groups, an iron-sulfur group and a specialized heme.
NO3-, high sucrose conc, and light induce the transcription of nitrite reductase mRNA.
Asparagine and glutamine repress the induction.
TLS Online TPP Program

#Id: 7930

#XL - Q Biochemistry

Secretory pathway
pathway of protein trafficking that flows through the ER
TLS Online TPP Program

#Id: 7929

#XL - Q Biochemistry

The ER captures selected proteins from the cytosol as they are being synthesized. These are of two types:

Transmembrane proteins

Water-soluble proteins
TLS Online TPP Program

#Id: 7928

#XL - Q Biochemistry

Muscle cells have an abundant, modified smooth ER called the sarcoplasmic reticulum.

The release and reuptake of Ca2+ by the sarcoplasmic reticulum trigger myofibril contraction and relaxation, respectively
TLS Online TPP Program

#Id: 7927

#XL - Q Biochemistry

Function of the ER:
most eukaryotic cells is to sequester Ca2+ from the cytosol (High concentration of Ca2+-binding proteins in the ER facilitates Ca2+ storage)
TLS Online TPP Program

#Id: 7926

#XL - Q Biochemistry

Rough ER, which is associated with ribosomes, functions in the synthesis and processing of secreted and membrane proteins
Smooth ER, which lacks ribosomes, functions in lipid synthesis.
TLS Online TPP Program

#Id: 7925

#XL - Q Biochemistry

Endoplasmic reticulum
Network of interconnected membranous structures within the cytoplasm of eukaryotic cells contiguous with the outer nuclear envelope.