In amphibians, at puberty, nuclear membrane of primary oocyte breaks down by the influence of
Progesterone breaks the nuclear membrane of primary oocyte.
Rolling of sheet of cells over other cells during gastrulation is called as :
Epiboly in gastrulation movement which is characteristic by rolling of sheet of cells leading to its thinning and spreading of cell layers.
Fast block to polyspermy in Sea Urchin is
Fast block to polyspermy is activated after the fusion of first sperm with the egg and involve a change in electrical potential of egg membrane
Embryonic stem cells are derived from
Embryonic stem cells are pluripotent and derived from inner mass of blastocyst which is undifferentiated.
Nuclear determinants are also called as
Nuclear determinants are called morphogens which determine morphogenesis.
In a bicoid mutant Drosophila ................... will form ?
Caudal gene shows its effect in anterior side also as bicoid won’t be able to inhibit its transcription. Hence, tail will form at both the sides.
The only cell that can give rise to a complete new organism is
The only cell that can give rise to a complete new organism is the fertilized egg (zygote) and this is described as totipotent
Concentration of bone morphogenetic protein is higher at
Concentration of BMP-4 is same at all the sides.
In case of chick development, primary organizer is called
In chick development, primary organizer is called Hensen’s node which forms the fate map further.
Which of the floral whorls is affected in agamous (ag) mutants ?
Agamous is present at the B and its mutation effect both petals and stamens.
With respect to development of any organism autonomous specification would result in which type of development?
During development, each cell is said to undergo autonomous specification i.e., if removed from the embryo, each cell develops according to its intrinsic instruction. It is also known as mosaic development.
In Hydra, if any part is lost remaining portion re-patterns itself and gives rise to complete organism. Such a pattern of development is termed as
This type of regeneration is called as morphallaxis.
Find out the correctly matched options
1) Radial cleavage - Ampliioxus. Echinodenns
2) Spiral cleavage - Annelids. Molluscs
3) Bilateral cleavage - Tunicates
4) Rotational cleavage - Mammals. Nematodes
Which of the following maternal effect genes regulate anterior axis development?
There are around 50 maternal genes which are involved in anterior-posterior axis specification, but out of the 50 genes, 4 genes are particularly important because their product form gradient along the axis and play important role.
Maternal effect genes are :
Maternal effect genes have all the characteristic present in options.
With respect to male reproductive system in humans, find out the correct statements.
Function of Noggin gene
Noggin is an antagonist of BMP and heeps in neural ectoderm not in skin ectoderm.
In developmental biology, morula is ________cell stage. [Answer in integer]
Morula is 16 celled stage.
As mammalian zygotes divide, all cells are totipotent upto the ________________ celled stage. [Answer in integer]
As embryo development progresses to the 8 cell stage and beyond depending on the species, the individual blastomeres that comprise the embryo gradually lose their totipotency.
If a sperm cell contains 8 chromosomes, it comes from an animal that has ______________ chromosomes. [Answer in integer]
Both the gametes (either sperm or egg) from each parent should contain half the total number of chromosomes for that species.
Primary spermatocyte undergoes 2nd meiotic divisions to produce how many haploid spermatids _______ [Answer in integer]
After second meiotic division the primary spermatocyte forms 4 haploid spermatids.