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.

TLS Online TPP Program

#Question id: 13552

#Unit 6. System Physiology – Plant

Transpiration from the leaf depends on two major factors;

TLS Online TPP Program

#Question id: 13553

#Unit 6. System Physiology – Plant

According this graph which statements is most appropriate ;

a) The air surrounding the leaf is very still, the layer of unstirred air on the surface of the leaf may be so thick that it is the primary deterrent to water vapor loss from the leaf   

b) The air surrounding the leaf is very still, reduces the thickness of the boundary layer at the leaf surface, reducing the resistance of this layer

c) The moving air reduces the thickness of the boundary layer at the leaf surface, reducing the resistance of this layer    

d) The moving air, the layer of unstirred air on the surface of the leaf may be so thick that it is the primary deterrent to water vapor loss from the leaf

TLS Online TPP Program

#Question id: 13554

#Unit 6. System Physiology – Plant

The microscopic stomatal pores provide a pathway for diffusional movement of gases across the epidermis and cuticle

TLS Online TPP Program

#Question id: 13555

#Unit 6. System Physiology – Plant

Water Loss Is Also Regulated by the Pathway Resistance

TLS Online TPP Program

#Question id: 13556

#Unit 6. System Physiology – Plant

The Guard Cells Have Specialized Features are

a) guard cells have a characteristic dumbbell shape, with bulbous ends

b) guard cells are always flanked by a pair of differentiated epidermal cells called subsidiary cells

c) guard cells are present in organs from more primitive plants, such as the liverworts and the mosses

d) dicot plants and nongrass monocots, kidney-shaped guard cells have an elliptical contour with the pore at its center

Which of the following combination of above statement is TRUE?

TLS Online TPP Program

#Question id: 13980

#Unit 6. System Physiology – Plant

The alignment of the cellulose microfibrils in the guard cell is