Answer:
It allowed us to put a formation date on some geologic crossections
Explanation:
Absolute dating is a newer way of evaluating the chronology of historical events by assigning numerical ages to them. The age thus assigned might not be the exact age but it is still closer to the real age.
It is unlike relative dating techniques which simply give the chronology or order of past events instead of the exact dates. Relative dating techniques have been in use before the emergence of absolute dating techniques in the twentieth century.
The answer is true, I believe, correct me if I am wrong
1. gamete
2. Genes, DNA, Chromosomes, Nucleus
3. Chromosomes are found in many places in the cell
Answer:
asks r
Explanation:
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Answer:
Explanation:
Pharmacophore (pharmacology) - The molecular framework responsible for a drug's biological activity. According to IUPAC — A pharmacophore is the ensemble of steric and electronic features that is necessary to ensure the optimal supramolecular interactions with a specific biological target structure and to trigger (or to block) its biological response.
Privileged structures are defined as molecular frameworks which are able of providing useful ligands for more than one type of receptor or enzyme target by judicious structural modifications.
1) The 1,4-dihydropyridine ring is present in many biologically important molecules that acts as an important scaffold for cardiovascular drug - a calcium antagonists and although it is technically not considered as a pharmacophore, it is considered as a privileged structure.
1,4-Dihydropyridine (DHP), belongs to the class of calcium antagonist that inhibits the influx of extracellular Ca+2 through the L-type voltage-dependent calcium channels.
A positional substitution in the 4-position is feasible in the heterocyclic ring which in turn culminates in various calcium channel antagonist activities and this heterocyclic ring is the common feature for various pharmacological activities such as anti-inflammatory activity, analgesic activity,
antihypertensive, antianginal, antitumor, antitubercular activity and antithrombotic .
Position on the heterocyclic ring binds to the L-type channel and also to N-type channel on membranes.
2.) The bioisosteres are not a suitable bioisostere for the traditional C-4 aryl or heteroaryl substitution which is necessary for calcium ion blockage thereby inhibiting it to function with the mechanism shared above.