Answer:
C but Humans burning fossil fuel is number 1
Please explain your answer
Answer:
a) the pyrimidine ring is assembled before being bonded to the ribose phosphate, whereas the purine ring is bonded to the ribose phosphate as it is formed
Explanation:
There are two ways for the synthesis of purines and pyrimidines:
- de novo synthesis-from basic simple units
- "recycling" synthesis-reuse of metabolites
Purines are synthesized directly on ribose sugar, in segments.
Pyrimidines are attached to the ribose after the synthesis of the base.
Answer:
C) Three hydrogen bonds will form with guanine.
Explanation:
Generally the DNA molecule is made up of Purines bases of Adenine and Guanine,and Pyrimidine of Cytosine and Guanine.However,RNA contains a different pyrimidine of Uracil.Thus the pairing is A-U am C-G.The uracil replaces Thymine.
The structure above is a Pyrimidine,because it is made up of single ring structure(an heterocylclic aromatic structure) compare to double structure of purines. Heterocyclic means it is ring form.Aromatic means it has resonance bonds which shift with the rings for stability.
It is also contains of two substitutes at position 4 of the ring structure (amineNH2) and at 2 which is the Keto group(=0).Therefore the structure is Cytosine.
In RNA structure the Cytosine pair with the three hydrogen bonds with guanine,while Adenine pair with Uracil.This ensures stability of the RNA structure.
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Evolution is the process by which an organism develops an adaptive mechanism to respond to selection forces.
Human evolution is similar to every evolution in the animal and plant kingdom. Forced by the environment both internal and external forces, animals adapted to the extreme conditions they were put in. As humans evovled, bacteria and other microorganisms also evolved to better attack and obtain food from other organisms including mankind. </span>
