Answer:
The delivery of the paternal genome to the egg is a primary goal of fertilization. In preparation for this step, the nucleus of the developing spermatozoon undergoes extensive morphological and biochemical transformations during spermatogenesis to yield a tightly compacted sperm nucleus. These modifications are essentially reversed during fertilization. As a result, the incorporated sperm nucleus undergoes many steps in the egg cytoplasm as it develops into a male pronucleus. The sperm nucleus (1) loses its nuclear envelope, (2) undergoes nucleoprotein remodeling, (3) decondenses and increases in size, (4) becomes more spherical, (5) acquires a new nuclear envelope, and (6) becomes functionally competent to synthesize DNA and RNA. These changes are coordinate with meiotic processing of the maternal chromatin, and often result in behaviors asynchronous with the maternal chromatin. For example, in eggs fertilized during meiosis, the sperm nucleus decondenses while the maternal chromatin remains condensed. A model is presented that suggests some reasons why this puzzling behavior exists. Defects in any of the processes attending male pronuclear development often result in infertility. New assisted reproductive technologies have been developed that ensure delivery of the sperm nucleus to the egg cytoplasm so that a healthy embryo is produced. An emerging challenge is to further characterize the molecular mechanisms that control sperm nuclear transformations and link these to causes of human infertility. Further understanding of this basic process promises to revolutionize our understanding of the mystery of the beginning of new life.
Explanation:
The delivery of the paternal genome to the egg is a primary goal of fertilization. In preparation for this step, the nucleus of the developing spermatozoon undergoes extensive morphological and biochemical transformations during spermatogenesis to yield a tightly compacted sperm nucleus. These modifications are essentially reversed during fertilization. As a result, the incorporated sperm nucleus undergoes many steps in the egg cytoplasm as it develops into a male pronucleus.
Answer:
D. all the sunshine in a lake
Answer;
-Telophase
Explanation;
-The spindle apparatus disintegrates during the telophase of mitosis. Telophase is the final stage of mitosis.
-During this phase, the sister chromatids reach opposite poles. The small nuclear vesicles in the cell begin to re-form around the group of chromosomes at each end.
-As the nuclear envelope re-forms by associating with the chromosomes, two nuclei are created in the one cell. Telophase is also marked by the dissolution of the kinetochore microtubules and the continued elongation of the polar microtubules.
Answer:
The complementary base pair is ATG TTT GTG ATA TGG CGC ATT TAC TAA
Explanation:
As per the complementary base pairing rule of DNA
C pairs with G and vice versa
A pairs with T (in DNA) or U (in RNA)
Breaking the given strand into triplets, we get -
TAC AAA CAC TAT ACC GCG TAA ATG ATT
ATG TTT GTG ATA TGG CGC ATT TAC TAA
Answer:
more glucose and change to a blacky-purple colour
Explanation:
