Which cell organelle is covered by only one unit membrane ?
Nucleus
Plastids
Mitochondria
Lysosome
The S-phase of cell cycle is characterized by:
duplication of chromosome
shotening of chromosome
duplication of DNA
duplicatin of centriole
Quiscent centre is present in :
root apex
shoot apex
parenchyma
collenchyma
A.
root apex
Quiescent centre is present in root apex. Clowes found a reservoir of cells having low DNA, RNA and protein concentration in root apex. These cells do not divide but may become active or they can made to divide. Due to its inactivity, the quiescent centre is resistant to damages.
Phytotron is :
a controlled condition chamber for tissue
leaf culture process
special culture of plants
root culture process
If centromere is the middle, the chromosome is called :
sub-metacentric
metacentric
acentric
telocentric
Which hormone is responsible for mobilization of storage food during seed germination ?
Auxin
Gibberellin
Cytokinin
Ethylene