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:
A. Some speculate that they were blown out to the islands by a massive storm
Explanation:
The common rosefinches are thought to have arrived on the Hawaii islands between 6 and 7 million years ago. As the common rosefinches are not big birds and they can not fly over very long distances, the scientists believe that it is a massive storm that blow some individuals to the Hawaii islands. This is nothing weird, as it has been witnessed numerous times how massive storms manage to carry some smaller birds to places where they are not able to fly on their own. Once there, the birds encountered suitable conditions for living and lot of open niches in the food chain. This resulted in quick diversification of the common rosefinches, with members of the species gradually adapting to a particular niche, experiencing changes to be more competent, and creating numerous new species after some time.
First of all the chloroplasts are only in plant cells and second the mitocondria is what stlres the proteins i think but idk
C. The nervous system sends signals to make muscles move.
Answer:
False
Explanation:
Smooth muscle is under autonomic nervous system control (which is something you cannot consciously control). Same thing is for cardiac muscle.
The only thing you can control is skeletal muscle like your hands and feet.
