Cellular senescence may have evolved to protect organisms against cancer. Instead of dividing out of control, the cells die. Cellular senescence appears to be regulated by several tumor suppressor genes, especially p53.what is the most appropriate reason behind this,

1) Transcription factor p53 is thought to suppress tumorigenesis by causing cell arrest and senescence in response to short telomeres, DNA damage, and viral or external signals to divide

2) This factor can stop the cell cycle, cause cellular senescence in rapidly dividing cells, instruct genes to initiate cellular apoptosis, and activate DNA repair enzymes.

3) Induction of apoptosis or cellular senescence by p53 always beneficial.

#Question id: 6978

#Unit 5. Developmental Biology

Removal of the apical ridge leads to

#Question id: 7286

#Unit 5. Developmental Biology

Which of the floral whorls is affected in apetala 3/pistillata (ap3/pi) mutants?

#Question id: 7290

#Unit 5. Developmental Biology

Following figure regarding to regulatory network in the Arabidopsis shoot meristem stem-cell niche.

A. The transcription factor WUS is synthesized in the cell A and moves via plasmodesmata into cell B, where one of its functions is to induce expression of the CLV3.

B. The transcription factor CLV3 is synthesized in the cell A and moves via plasmodesmata into cell B, where one of its functions is to induce expression of the WUS.

C. Secreted CLV3 protein from cell B binds to the receptor protein kinase on the surface of cell A; there, it activates a signal that represses WUS transcription.

D. Secreted WUS protein from cell B binds to the receptor protein kinase on the surface of cell A; there, it activates a signal that represses CLV3 transcription.

Which of the following combination is correct?

#Question id: 7292

#Unit 5. Developmental Biology

How is plant cell cytokinesis different from animal cell cytokinesis?

#Question id: 7293

#Unit 5. Developmental Biology

In agamous mutant (flower within flower phenotype) which of the following statements is valid?

#Question id: 7294

#Unit 5. Developmental Biology

Multiple factors regulate flowering in Arabidopsis. FT mRNA is expressed in companion cells of the leaf vein in response to multiple signals, including day length, light quality, and temperature. FT moves in the phloem from leaves to the apical meristem. FT is unloaded from the phloem in the meristem and interacts with FD.

FT-FD complex activates multiple genes. Which of the following combination is correct?(SS)