How many haploid nuclei are present in a mature pollen grain
One
Two
Three
Four
B.
Two
Mature pollen grain carries two haploid nuclei which moves into the cytoplasm of the synergid.
One of the male gametes moves towards the egg cell and fuses with its nucleus thus completing the syngamy. This results in the formation of a diploid cell, the zygote. The other male gamete moves towards the two polar nuclei located in the central cell and fuses with them to produce a triploid primary endosperm nucleus (PEN)
Assertion: Pulmonary circulation consists of flow of deoxygenated blood from right ventricle to the lungs and flow of oxygenated blood from lungs to the left atrium.
Reason: Systemic circulation consists of flow of oxygenated blood from the left ventricle to all parts of the body and deoxygenated blood from different parts to right atrium.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
Assertion: Adrenocorticotropic-Releasing Hormones (ARH) excite the anterior lobe of
pituitary gland to produce adrenocorticotropic hormone (ACTH).
Reason: ACTH stimulates the adrenal cortex to secrete its glucocorticoid and mineralocorticoid hormones.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
Which of the following occurs due to monosomy of sex chromosome
Down's syndrome
Turner's syndrome
Haemophilia
Sickle cell anaemia
Somaclones are prepared by
callus culture
sexual reproduction
micropropagation
somatic hybridisation
Which of the following associations shows mutualism
Fig and wasp
Barnacles on whale
Roundworms in human intestine
Orchids on mango tree
In cloning of cattle a fertilized egg is taken out of the mother's womb and
in the eight cell stage, cells are separated and cultured untill small embryos are formed which are implanted into the womb of other cows
in the eight cell stage the individual cells are separated under electrical field for further development in culture media
from this upto eight identical twins can be produced
the egg is divided into 4 pairs of cells which are implanted into the womb of other cows.
