Answer:
d. nitrogen-containing base
.
Explanation:
A nucleotide comprises a phosphate group, a pentose sugar and a nitrogenous base (nitrogen-containing base).
A nitrogenous base is a type of aromatic heterocyclic organic compound which essentially has nitrogen in it. The base can be a purine or pyrimidine. Purine nitrogenous bases are adenine (A) and guanine (G) while pyrimidine nitrogenous bases are cytosine (C), thiamine (T) and uracil (U).
Till the time a base is not attached to covalently linked phosphate group and a pentose sugar, it is known as nucleoside. But as soon as we attach any nitrogenous base to the nucleoside, a nucleotide is formed. So it means a nucleotide is nucleoside + nitrogenous base.
Examples are as under:
A nucleotide which has adenine as nitrogenous base is known as adenosine triphosphate (ATP) while a nucleotide which has guanine as nitrogenous base is known as Guanosine-5'-triphosphate (GTP).
This means that a single carbon atom can form up to tetravalent bonds with other atoms
The cellular process shown in the image as x, y and z are mentioned below:
X is Replication. It is the process by which double- DNA Replication is the process by which double stranded DNA makes its own copies. Each strand on its separation, synthesizes a complementary stand.
Y is Transcription. It is the process by which copying of the information from a strand of DNA into a new molecule of mRNA, with the help of an enzyme RNA polymerase.
Z is Translation. It is the process in which genetic code on mRNA is decoded to produce the specific sequence of amino acids to form a polypeptide chain.
The question is asking to choose among the following choices that states the length of time that an organism expected to live, and base on my research and further investigation, I would say that the answer would be A. life span. I hope you are satisfied with my answer and feel free to ask for more
