1. The term "embryo" denotes the juvenile stage of an animal while it is contained in the egg or the maternal body.
2. The processes that are involved in the transformation of the fertilized egg into a new adult individual are called ontogenic development.
3. Only gametes or generative cells go through the process of maturation or meiosis.
4. Historical development of species is called phylogenetic development.
5. Blastogenesis is the development of new individuals using asexual reproduction.
6. The third phase of development is Cleavage.
7. The proliferating cells in the ovaries are called oogonia.
8. Muscles and blood vascular system are made up of mesoderm.
9. The resulting embryo by infolding of the mesoderm and endoderm is called the gastrula.
10. Blastopore becomes the oral opening in Coelenterata.
11. The formation of spermatozoon and ripening of the egg is called gametogenesis.
12. The second phase of development is fertilization.
13. Endoderm forms the alimentary canal and the digestive glands.
14. Cleavage cells are called blastomeres.
15. The fifth phase of development is the phase of organogenesis.
16. In cleavage, the cells are arranged in a hollow spherical body called a blastula.
17. The group of cells that are segregated from the other cells of the embryo to form an organ is called the rudiment of the respective organ.
18. Larva possesses special organs which are absent in adults.
19. Developmental processes may be repeated in an adult during regeneration.
20. Ectoderm always gives rise to the skin epidermis and the nervous system.
21. When single layers of cells called blastoderm give rise to two or more layers of cells, germinal layers are formed.
22. The fourth phase of development is gastrulation.
23. The more general features in the embryo developed earlier than the more special features is the statement of Baer's Law.
24. Biogenetic law is proposed by Muller and Hackel.
25. The groups of animals having a common basic plan of organization are called the phyla of the animal kingdom.
26. The sixth phase of development is the period of growth and histological differentiation.
27. The generation of cellular diversity is called differentiation.
28. Some cells that can form new structures even in adults are called stem cells.
29. The gametes and their precursor cells are collectively called germ cells.
30. Aristotle supported the idea of epigenesis, which states that the organs of the embryo are formed de novo at each generation.
31. The organs are already present within the egg or sperm in miniature form is the theory of preformation.
32. In Deuterostomia, the blastopore develops into the anus.
33. Biogenetic law states that ontogeny is a shortened and modified recapitulation of the phylogeny.
34. The parts of the alimentary canal lined by ectoderm adjoining the mouth are known as the stomodeum.
35. The creation of an ordered form that involves coordinating cell growth, cell migration, and cell death is called morphogenesis.
36. The developmental pathway from germ cell to mature sperm is called spermatogenesis.
37. When sperm stem cells increase by mitosis, this is the proliferative phase.
38. GDNF is a paracrine factor called the Glial cell line-derived neurotrophic factor.
39. The precursors of sperm and oocyte are called Primordial germ cells.
40. The phase in which the round cells called spermatids eject most of their cytoplasm and become streamlined sperm is called spermiogenesis.
41. Gonocytes are true stem cells.
42. Sertoli cells nourish the developing sperm.
43. Type A spermatogonia can generate more than 1000 sperm per second in adult human males.
44. GDNF promotes the division of spermatogonial stem cells.
45. Stem Cell Factor promotes the transition to spermatogenesis.
46. Spermatogonia with high levels of stra8 divide to become type B spermatogonia.
47. Primary spermatocytes undergo meiosis to yield secondary spermatocytes.
48. The haploid cells formed from secondary spermatocytes called spermatids.
49. Acrosomal vesicle of sperm constructed from Golgi apparatus.
50. The acrosome forms a cap that covers the sperm nucleus.
No comments:
Post a Comment