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In DNA, the number of A - VCE - SSCE Biology - Question 8 - 2003 - Paper 1
Question 8
In DNA, the number of A. phosphate groups equals the number of nitrogen bases. B. adenine nucleotides equals the number of cytosine nucleotides. C. phosphate groups ... show full transcript
Worked Solution & Example Answer:In DNA, the number of A - VCE - SSCE Biology - Question 8 - 2003 - Paper 1
Step 1
A. phosphate groups equals the number of nitrogen bases.
Answer
This statement is incorrect. In DNA, the number of phosphate groups does not equal the number of nitrogen bases. Each nucleotide comprises one phosphate group, one sugar, and one nitrogen base. Therefore, while there are many nitrogen bases, there are typically fewer phosphate groups when considering the difference in nucleotide structures.
Step 2
B. adenine nucleotides equals the number of cytosine nucleotides.
Answer
This statement is also incorrect. The number of adenine nucleotides (A) does not necessarily equal the number of cytosine nucleotides (C) in DNA. The quantity of these nucleotides varies, as adenine pairs with thymine (T) while cytosine pairs with guanine (G).
Step 3
C. phosphate groups equals twice the number of sugar molecules.
Answer
This statement is incorrect. In a DNA molecule, each nucleotide consists of one phosphate group, one sugar, and one nitrogen base. Therefore, the number of phosphate groups is equal to the number of sugar molecules, not twice as many.
Step 4