KNOX gene expression increases cytokinin levels in the shoot apical meristem by upregulating the cytokinin biosynthetic gene ISOPENTENYL TRANSFERASE7 (IPT7)

TLS Online TPP Program

#Id: 1514

#Unit 2. Cellular Organization

Most microtubules in a cell consist of a simple tube, a singlet microtubule, built from 13 protofilaments. 

TLS Online TPP Program

#Id: 1515

#Unit 2. Cellular Organization

Doublet contains one complete 13-protofilament microtubule (A tubule) and one additional tubules (B tubule) consisting of 10 protofilaments.

 

TLS Online TPP Program

#Id: 1516

#Unit 2. Cellular Organization

Triplet contains one complete 13-protofilament microtubule (A tubule) and two additional tubules (B & C tubule) consisting of 10 protofilaments each.

TLS Online TPP Program

#Id: 1517

#Unit 2. Cellular Organization

All microtubules are nucleated from structures known as microtubule-organizing centers, or MTOCs.

 

TLS Online TPP Program

#Id: 1518

#Unit 2. Cellular Organization

In MTOCs, 

The (−) end of the microtubule stays anchored in the MTOC while the (+) end extends away from it.

TLS Online TPP Program

#Id: 1519

#Unit 2. Cellular Organization

In cilia and flagella,

microtubules are assembled from an MTOC called a basal body.