Question

Which one of the following statements is correct?
A. DNA consists of a core of eight histones
B. The centromere is found in animal cells, which produces aster during cell division
C. The gene for producing insulin is present in all human cells
D. The nucleosome is formed only of the nucleotides

Answer 1

Hint: The octamer of the core of DNA contains eight histone proteins. The nucleosome is formed with the octamer, a histone protein, and the DNA. The centromere is found between the arms of all the chromosomes. Moreover, the gene that controls the levels of sugar in the blood is found in all the cells.

Complete answer: The first statement is DNA consists of a core of eight histones: In eukaryotes, the core of the DNA molecule along with the DNA is known as the nucleosome. Eukaryotes have positively charged and basic histone proteins. There are five different kinds of histone proteins. Four of these occur in pairs. They form the octamer or the nu-body together. One protein is found attached to them separately. Collectively all these nine histone proteins form the core of the DNA. The DNA strand is wrapped around this histone octamer. Thus, this statement is incorrect.
-The second statement is that the centromere is found in animal cells, which produces aster during cell division: The centromere is the primary constriction that is present in all the chromosomes, be that of plants or animals. The centromere holds the two arms of the chromosome together. It also holds the chromatids together during the division of the cell. Thus, this statement is incorrect.
-The third statement is that the gene for producing insulin is present in all human cells: The gene for producing insulin is present in all cells of the human body. However, it is inactive in all these cells. It gets activated only in the beta cells of the Islet of the Langerhans of the pancreas. Due to this reason, only these cells are responsible for producing insulin in the body. Thus, this statement is correct.
-The fourth statement is that the Nucleosome is formed only of the nucleotides: The nucleosome is formed by the histone proteins and the DNA wrapped around it. Eight histone proteins that are found in the pairs form the octamer. One histone protein is found attached to it freely. Together they form the core and the DNA is wrapped around it. DNA is made up of nucleotides. The nucleotides are the basic unit of DNA. Thus, this statement is incorrect.
Thus, based on the above information we can conclude that the statement the gene for producing insulin is present in all human cells is correct.
Hence, the correct answer is option C.

Note: The insulin hormone helps in maintaining the sugar levels of the blood. Insulin does glycogenesis in the liver. Glycogenesis is the conversion of the extra blood sugar or glucose into glycogen. The deficiency of insulin hormone in the body causes diabetes mellitus.