A new DNA strand elongate only in the 5' to 3' direction during DNA replication because the "polarity of the DNA molecule prevents addition of nucleotides at the 3' end" .
DNA replication occurs in the 5' to 3' direction. DNA polymerase can only add nucleotides to the 3' OH group of the growing DNA strand, this is why DNA replication occurs only in the 5' to 3' direction.
DNA polymerase can only add to the 3' end, so the 5' end of the primer remains unaltered. Consequently, synthesis proceeds immediately only along the so-called leading strand.
Hence, the correct answer will be option (B)
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Answer:
A) Calcitonin injection
Explanation:
Parafollicular cells or C-cells of the thyroid gland produce a hormone which is involved in the regulation of calcium levels in the blood. This hormone is Calcitonin. It works in an antagonistic manner with the Parathyroid hormone (PTH). Calcitonin decreases the calcium level in the blood by increasing absorption of calcium ions in bones. In osteoporosis, when the patient is given the injection of hormone calcitonin, it produces and increase in bone mass because it negatively affects the rate of absorption of bone by the osteoclasts.
Beta thalassemia is a blood disorder that reduces the production of hemoglobin
