Read the following statements and select the correct option.
(i) Loosely packed and lightly stained region of chromatin are called as heterochromatin.
(ii) Densely packed and dark stained region of chromatin are called as euchromatin.
(iii) A typical nudeosome contains $200$ bp of $DNA$ helix
- Statements (i) and (ii) are true, but statement (iii) is false
- Statements (i) and (ii) are false, but statement (iii) true
- Statements (ii) and (iii) are true, but statement (iv) false
- All the statements are true
The Correct Option is B
Solution and Explanation
Top Questions on Structure of DNA and RNA
- Given below are two statements: Statement I: In the RNA world, RNA is considered the first genetic material evolved to carry out essential life processes. RNA acts as a genetic material and also as a catalyst for some important biochemical reactions in living systems. Being reactive, RNA is unstable.
Statement II: DNA evolved from RNA and is a more stable genetic material. Its double helical strands being complementary, resist changes by evolving repair mechanisms. In the light of the above statements, choose the most appropriate answer from the options given below:- NEET (UG) - 2025
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- Nitrogen base not present in DNA:
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- Two statements, Assertion and Reason are given. Choose the correct option from the following.
Assertion: In the secondary structure of RNA, double helix structure is formed.
Reason: In the double structure of RNA, two nucleic acid chains are wound about each other and held together by hydrogen bonds between pairs of bases.- COMEDK UGET - 2024
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- Which of the following is not present in RNA?
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- Approximately how long is the DNA molecule in a single human cell if stretched out?
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Concepts Used:
Structure of DNA and RNA
DNA Structure:
Human DNA is unique and is made up of 3 billion base pairs. However, 99% of them are the same in all humans. The sequence of these bases determines what information needs to be coded that is necessary for the organism's growth and development. During the process of transcription (when DNA is replicated), a product is formed known as RNA (Ribonucleic Acid). This RNA is responsible for translating genetic information from DNA to protein followed by reading through ribosomes.
Read More: Structure of DNA
RNA Structure:
The ribonucleic acid has all the components same to that of the DNA with only 2 main differences within it. RNA has the same nitrogen bases called the adenine, Guanine, Cytosine as that of the DNA except for the Thymine which is replaced by the uracil. Adenine and uracil are considered as the major building blocks of RNA and both of them form base-pair with the help of 2 hydrogen bonds.
RNA resembles a hairpin structure and like the nucleotides in DNA, nucleotides are formed in this ribonucleic material(RNA). Nucleosides are nothing but the phosphate groups which sometimes also helps in the production of nucleotides in the DNA.
Read More: Structure of RNA