Organisms that are denser than their surrounding water, a variety of adaptations can either reduce an organism’s density or retard its rate of sinking.

TLS Online TPP Program

#Id: 9005

#Unit 6. System Physiology – Plant

Most of the regulation between nucleus and plastids is anterograde: products of nuclear genes control the transcription and translation of plastid genes..

TLS Online TPP Program

#Id: 9006

#Unit 6. System Physiology – Plant

The signals flow from the chloroplast to the nucleus is retrograde:

plastidial ferrochelatase I catalyzes the synthesis of heme, which in turn regulates the expression of nuclear encoded, chloroplast‐targeted proteins in greening leaves.

TLS Online TPP Program

#Id: 9007

#Unit 6. System Physiology – Plant

Forms I, II, and III are catalytically competent, while members of form IV lack Rubisco activity and play other roles in metabolism.

TLS Online TPP Program

#Id: 9008

#Unit 6. System Physiology – Plant

Form I is the only type of Rubisco that harbors small subunits, and it consists of eight large and eight small subunits [L8S8]: Four dimers of large subunits [L2]4 capped by four small subunits at the top and the bottom [S4]2 build the hexadecameric structure {[S4]•[L2]4•[S4] = L8S8}

TLS Online TPP Program

#Id: 9009

#Unit 6. System Physiology – Plant

The assembly chaperone (RbcX)2 help to fold RUBISCO

TLS Online TPP Program

#Id: 9010

#Unit 6. System Physiology – Plant

Only three molecules of CO2 are fixed per second per molecule of rubisco at 250C.