why are u asking it........
Answer:
Okay
Explanation:
Human topoisomerase I plays an important role in removing positive DNA supercoils that accumulate ahead of replication forks. It also is the target for camptothecin-based anticancer drugs that act by increasing levels of topoisomerase I-mediated DNA scission. Evidence suggests that cleavage events most likely to generate permanent genomic damage are those that occur ahead of DNA tracking systems. Therefore, it is important to characterize the ability of topoisomerase I to cleave positively supercoiled DNA. Results confirm that the human enzyme maintains higher levels of cleavage with positively as opposed to negatively supercoiled substrates in the absence or presence of anticancer drugs. Enhanced drug efficacy on positively supercoiled DNA is due primarily to an increase in baseline levels of cleavage. Sites of topoisomerase I-mediated DNA cleavage do not appear to be affected by supercoil geometry. However, rates of ligation are slower with positively supercoiled substrates. Finally, intercalators enhance topoisomerase I-mediated cleavage of negatively supercoiled substrates but not positively supercoiled or linear DNA. We suggest that these compounds act by altering the perceived topological state of the double helix, making underwound DNA appear to be overwound to the enzyme, and propose that these compounds be referred to as ‘topological poisons of topoisomerase I’
Answer:
Option b) chromosomes
Explanation:
The correct answer for the given question is option (b) Chromosomes.
The whole structure of the sperm contains the various components which are
as follows:
The head of the sperm contains the nucleus and the chromosomes
The neck contain of the sperm contains the mitochondria
the tail of the sperm contains the flagella.
The nurse administers cimetidine to a 75-year-old client diagnosed with a Gastric ulcer the nurse should monitor the client for the following adverse reactions Headache, Sleepiness, Confusion, Dizziness, Nausea which contribute for the change in Metal status.
- Cimetidine is a H
Receptor Antagonist. - Gastric partial cells contains receptors for Histamine.
- Histamine is released from the Enterochromaffin cells upon the stimulation from food intake or from Vagus nerve stimulation.
- Thus Histamine released from Enterochromaffin cells binds to H receptors on the parietal cells and increases the secretion of HCl.
- Cimetidine has totally opposite effect and decreases the secretion of HCl from the parietal cells.
- Not only on gastric cells H receptors are also present in CNS where they stimulate brain cells.
- The above point justifies the adverse effects of Cimetidine.
- Patients over the age of 50 or those who are severely ill may experience transient confusion while taking H
blockers, particularly cimetidine.
Hence from these points we can conclude that patients who are above 50 years and receiving Cimetidine medication for gastric ulcer should be monitored for the above mentioned adverse reactions.
Learn more about Gastric Ulcer:
brainly.com/question/27928601
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