Multiple Choice
Which set correctly lists the four nitrogenous bases found in DNA?
38
views
7. DNA and Chromosome Structure
DNA Structure
Multiple Choice
In the DNA double helix, what holds the two antiparallel strands together?
A
Hydrogen bonds between complementary base pairs (A–T and G–C)
B
Ionic bonds between the phosphate groups of opposite strands
C
Covalent phosphodiester bonds between bases across the two strands
D
Peptide bonds between nucleotides in each strand
Verified step by step guidance1
Understand the structure of the DNA double helix: it consists of two antiparallel strands made up of nucleotides.
Recall that each nucleotide contains a sugar, a phosphate group, and a nitrogenous base (A, T, G, or C).
Identify the types of bonds within and between strands: phosphodiester bonds connect nucleotides within the same strand, forming the sugar-phosphate backbone.
Recognize that the two strands are held together by hydrogen bonds between complementary nitrogenous bases: adenine (A) pairs with thymine (T) via two hydrogen bonds, and guanine (G) pairs with cytosine (C) via three hydrogen bonds.
Note that ionic bonds do not hold the strands together across the helix, and peptide bonds are not involved in DNA structure as they link amino acids in proteins.
Related Videos
Related Practice
