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:
Answer is option B - "I should shower rather than take a tub bath."
Explanation:
Abdominal hysterectomy is the surgical removal of a part or all of the uterus by making an incision in the lower abdomen. After the surgery, the patient normally spends 2 - 5 days in the hospital and takes at least 4 - 6 weeks to get completely better. Some of the major discharge instructions are;
- Drink enough water and eat smaller meals that are rich in proteins and fiber and plenty of fruits and vegetables daily. This helps with the healing process and prevents constipation.
- Avoid swimming or taking a tub bath, but can take showers.
- Dressings over the incision should be removed daily and keep the wound area clean.
- Avoid inserting anything such as tampons into the vagina for 6 weeks after the surgery.
- Avoid all heavy activity including strenuous household activities, weightlifting, and other strenuous exercises. Short walking and light household chores can be done.
- Avoid driving if the patient is taking narcotic pain-relieving medicines. Long trips in vehicles or airplanes are not recommended for 4 weeks after the surgery.
<em>When water is abundant:</em>
-Temporal regulation of stomata is used:
Open during the day
Closed at night
- At night, there is no photosynthesis, so no demand for CO2 inside the leaf.
- Sunny day = demand for CO2 in leaf is high = stomata wide open.
- As there is plenty of water, plant trades water loss for photosynthesis products.
- If the leaf's CO2 concentration is low, the stomata will stay open to continue fueling photosynthesis.
- High temperatures will also signal stomata to close.
- When limited water is available in the soil, plants try to prevent water loss.
During photosynthesis, carbohydrates are produced.
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