Negative control of the lac operon. 

No lactose; repression. The lacI gene produces repressor, which binds to the operator and blocks RNA polymerase from transcribing the lac genes.

TLS Online TPP Program

#Id: 8188

#Unit 2. Cellular Organization

Plasmalogens

• most abundant class of PL in myelin sheaths

• Analogous to PC

• Contain an unusual fatty alcohol that is attached through an ether linkage.

TLS Online TPP Program

#Id: 8189

#Unit 2. Cellular Organization

C-terminal peroxisomal signal sequences Ser–Lys–Leu (PTS1)

N-terminal peroxisomal signal sequences slightly longer and partially hydrophobic (PTS2)

TLS Online TPP Program

#Id: 8190

#Unit 2. Cellular Organization

Peroxins

Catalyse peroxisomal protein import by ATP hydrolysis.

TLS Online TPP Program

#Id: 8191

#Unit 2. Cellular Organization

PTS1 signals are recognized by the peroxin Pex5 receptor

PTS2 signals are recognized by the peroxin Pex7 receptor

Neither targeting sequence is cleaved after import.

TLS Online TPP Program

#Id: 8192

#Unit 2. Cellular Organization

Catalase, are synthesized as precursors with PTS1

Thiolase, are synthesized as precursors with PTS2

TLS Online TPP Program

#Id: 8193

#Unit 2. Cellular Organization

Pex5 forms a multimeric complex with the Pex14 receptor located on the peroxisomal membrane.