2023 Molecular Basis of InheritanceThe Structure of DNA and Packaging of DNA Helix Medium Question 31 of 200 in Molecular Basis of Inheritance

Given below are two statements: Statement I: In prokaryotes, the positively charged DNA is held with some negatively charged proteins in a region called nucleoid. Statement II: In eukaryotes, the negatively charged DNA is wrapped around the positively charged histone octamer to form nucleosome. In the light of the above statements, choose the correct answer from the options given below:

A Statement I is incorrect but Statement II is true.
B Both Statement I and Statement II are true.
C Both Statement I and Statement II are false.
D Statement I is correct but Statement II is false.

The answer is A.

Solution

DNA is negatively charged and is held by positively charged proteins, so Statement I is incorrect.

In prokaryotes, such as E. coli, though they do not have a defined nucleus, the DNA is not scattered throughout the cell. DNA (being negatively charged) is held with some proteins (that have positive charges) in a region termed as 'nucleoid'. The DNA in nucleoid is organised in large loops held by proteins.

Concept nucleoid and nucleosome

Molecular Basis of Inheritance in past papers

200 questions from this chapter have appeared across 27 exam years.