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: 1) When phosphorous is not bound in rocks, it moves quickly through land food webs. Constant use of phosphate-rich fertilizers will help increase phosphorus availability to plants, thus ultimately helping our ecosystems.
3) Minimizing the use of ammonia-rich fertilizers on lawns would not add excess nitrogen to the nitrogen cycle. As a result, it would help decrease the pollution of food webs in the oceans, decrease soil acidity on land, and decrease the amount of greenhouse gases in the atmosphere
Explanation:
The nitrogen and phosphorus cycles both are biochemical cycles. The nitrogen cycle involves the process of uptake of nitrogen from the atmosphere by the soil bacteria which is then become available to the plants for plant growth, from plants it is transferred to the other organisms in different forms.
The phosphorus is found in the rocks and these rocks wither and the inorganic phosphorus become available to the ecosystems.
Option 1 is correct, this is because the phosphorus is available on earth in the inorganic form inside the rocks, the withering and erosion processes make the phosphorus available to the plants. Another source of phosphorus to plants is phosphorus rich fertilizers. Thus plants will absorb phosphorus and grow. These plants will be consumed by other organisms thus the ecosystem will remain healthy.
Option 3 is correct, this is because nitrogen rich fertilizers can cause eutrophication in water bodies, or can contaminate the water. It will decrease the pH of the soil due to the formation of nitric acid. Also the nitrogen dioxide is the greenhouse gas.
Tapeworms are known to feed off of their hosts to complete their life cycle. This type of symbiotic relationship is called parasitism. Parasitism is defined as the type of symbiotic relationship wherein only one of the two interacting organisms benefit, at the latter organism's expense. Parasites could either be found inside or outside the host's body. Tapeworms are internal parasites.
The answers are:
- very high humidity
- vines
- palms
- highest species diversity
- gorillas
Rainforests have very high humidity because it rains throughout the whole year and is constant summer, so the precipitation and high temperature contribute to very high humidity.
The rainforests have the highest species diversity of any biome, both animals, and plants, including plants like the vines that crawl on the other trees and the palms, as well as animals like the gorilla in Africa, in the Congo basin.
Answer:
coccus, rod or bacillus, and spiral
