Which of the following statements regarding DNA is false?
A. DNA uses the nitrogenous base uracil
B. DNA molecules can include four different nucleotides in its structure
C. DNA molecules have a sugar-phosphate backbone
D. DNA uses the sugar deoxyribose
The Correct Answer and Explanation is :
Correct Answer:
A. DNA uses the nitrogenous base uracil
Explanation:
DNA (Deoxyribonucleic Acid) is the genetic material found in most living organisms, carrying instructions necessary for growth, development, functioning, and reproduction. It consists of nucleotides, which include a phosphate group, a deoxyribose sugar, and a nitrogenous base. Let’s analyze each statement carefully:
- Statement A (False): DNA uses the nitrogenous base uracil
- This statement is incorrect because DNA does not contain uracil (U). Instead, DNA contains thymine (T).
- Uracil is found in RNA (Ribonucleic Acid), where it replaces thymine.
- In RNA, the nitrogenous bases are adenine (A), guanine (G), cytosine (C), and uracil (U), whereas in DNA, they are adenine (A), guanine (G), cytosine (C), and thymine (T).
- Statement B (True): DNA molecules can include four different nucleotides in its structure
- DNA is composed of four nucleotides: adenine (A), guanine (G), cytosine (C), and thymine (T).
- Statement C (True): DNA molecules have a sugar-phosphate backbone
- DNA has a sugar-phosphate backbone, which provides structural support. The backbone is composed of alternating deoxyribose sugars and phosphate groups linked by phosphodiester bonds.
- Statement D (True): DNA uses the sugar deoxyribose
- DNA contains deoxyribose, a five-carbon sugar that lacks one oxygen atom at the 2′ position, distinguishing it from RNA’s ribose sugar.
Since Statement A is incorrect, it is the false statement.
Now, I’ll generate an image representing the structure of DNA.
Here is a 3D-rendered digital illustration of a DNA double helix, showing the sugar-phosphate backbone and nitrogenous base pairs in a spiral structure. Let me know if you need any modifications or additional explanations!
