A mature pollen grain of Pinus has
2 cells
3 cells
4 cells
5 cells
C.
4 cells
In Pinus, the microspore nucleus divides by a periclinal wall and forms a very small prothallial cell and large central cell. The central cell cuts off a second prothallial cell and antheridial cell. The nucleus of the antheridial cell divides to form generative cell and tube cell. Thus, the pollen grain of Pinus is shed at four cell stage when it consists of two vegetative prothallial cells, a generative cell and a tube cell.
In mitochondria, enzyme cytochrome oxidase is present in
Outer membrane
Perimitochondrial space
Inner Membrane
Matrix
Darwin’s finches are an excellent example of
Adaptive Radiation
Seasonal migration
Brood parasitism
Connecting links
Nitrogen-fixation in root nodules of Alnus is brought about by
Bradyrhizobium
Clostridium
Frankia
Azorhizobium
In which one of the following, the male and female gametophytes don’t have free-living independent existence?
Pteris
Funaria
Polytrichum
Cedrus
During the propagation of a nerve impulse, the action potential results from the movement of
K+ ions from extracellular fluid to intracellular fluid
Na+ ions from intracellular fluid to extracellular fluid
K+ ions from intracellular fluid to extracellular fluid
Na+ ions from extracellular fluid to intracellular fluid
