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:
Molecular chaperons in the cells helps in protein folding. These are the group of proteins that have functional similarity and they also assist protein folding.
They have the ability to prevent the non specific binding and aggregation by the binding of the non native proteins.
Molecular chaperons helps in recognizing the hydrophobic surfaces of the unfolded proteins because they themselves are hydrophobic in nature and will combine to the hydrophic binding and bonding.
This helps in guiding the protein to folding.
Explanation:
The motion of atoms and molecules produces a form of energy that is present in all matter, called heat or thermal energy. ... Energy can take many forms, and from one form to another, it can alter. Many different energy forms can be transformed into heat energy
Answer:
The answers are c)are the most reinforcing, generate the greatest immediate sensual appeal, and produce the most powerful psychological dependence.
Explanation:
Like all psychoactive substances, amphetamines affect the central nervous system and have stimulating effects (empathy, sensuality, confusion, etc.), producing an alert state along with various reactions in perception. Some individuals also report optical and auditory illusions. On many occasions this is also favored by the existence of intense visual and auditory stimuli, as happens for example at parties. However, most of these desired effects have tolerance with repeated doses of the same substances and even cross tolerance with doses of other substances. With the appearance of this tolerance other effects appear such as aggressiveness, anxiety symptoms, panic attacks, etc.
Among the medical complications related to the use of these substances, acute neurological complications, seizures and cerebrovascular diseases stand out.
