Question 22 (1 ?point)
Which statements about DNA are false?
DNA nucleotides come in four different varieties
DNA nucleotides contain one phosphate group
DNA nucleotides contain the sugar called ribose
DNA nucleotides come in long single strands
The Correct Answer and Explanation is:
Correct Answer:
✅ DNA nucleotides contain the sugar called ribose
✅ DNA nucleotides come in long single strands
These two statements are false.
Explanation
DNA (Deoxyribonucleic Acid) is a complex molecule that stores genetic information essential for life. Understanding its composition and structure is fundamental to biology. The question asks which statements about DNA are false, and two of them clearly are:
- “DNA nucleotides contain the sugar called ribose” – This is false. DNA nucleotides actually contain a sugar called deoxyribose, not ribose. Ribose is found in RNA (Ribonucleic Acid). The difference is that deoxyribose lacks one oxygen atom compared to ribose. This small change significantly affects the stability and structure of DNA versus RNA.
- “DNA nucleotides come in long single strands” – This is also false. DNA typically exists as a double-stranded helix, where two complementary strands are held together by hydrogen bonds between nitrogenous bases. While single-stranded DNA (ssDNA) can exist in some viruses or experimental settings, the natural and most stable form of DNA in cells is double-stranded (dsDNA).
The other two statements are true:
- “DNA nucleotides come in four different varieties” – This is correct. DNA nucleotides differ by their nitrogenous base: adenine (A), thymine (T), cytosine (C), and guanine (G).
- “DNA nucleotides contain one phosphate group” – This is also true. Each DNA nucleotide consists of three components: a deoxyribose sugar, a phosphate group, and one of the four nitrogenous bases. The phosphate group links the sugars of adjacent nucleotides, forming the DNA backbone.
Understanding these basics is crucial for grasping how genetic information is stored, copied, and transmitted in living organisms. Misconceptions between DNA and RNA components are common but easily clarified with foundational knowledge of molecular biology.
