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1. Introduction to Genetics51m
2. Mendel's Laws of Inheritance3h 37m
3. Extensions to Mendelian Inheritance2h 41m
4. Genetic Mapping and Linkage2h 28m
5. Genetics of Bacteria and Viruses1h 21m
6. Chromosomal Variation1h 48m
7. DNA and Chromosome Structure56m
8. DNA Replication1h 10m
9. Mitosis and Meiosis1h 34m
10. Transcription1h 0m
11. Translation58m
12. Gene Regulation in Prokaryotes1h 19m
13. Gene Regulation in Eukaryotes44m
14. Genetic Control of Development44m
15. Genomes and Genomics1h 50m
16. Transposable Elements47m
17. Mutation, Repair, and Recombination1h 6m
18. Molecular Genetic Tools19m
- Genetic Cloning
  9m
- Methods for Analyzing DNA
  9m
19. Cancer Genetics29m
- Overview of Cancer
  21m
- Cancer Mutations
  7m
20. Quantitative Genetics1h 26m
21. Population Genetics50m
- Hardy Weinberg
  19m
- Allelic Frequency Changes
  31m
22. Evolutionary Genetics29m

7. DNA and Chromosome Structure

DNA Structure

Genetics

7. DNA and Chromosome Structure

DNA Structure

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Multiple Choice

Which type of force is primarily responsible for holding the two strands of DNA together in the double helix?

Ionic interactions between sugar molecules

Covalent bonds between phosphate groups

Van der Waals forces between backbone atoms

Hydrogen bonds between complementary nitrogenous bases

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Verified step by step guidance

Identify the structural components of the DNA double helix: two strands composed of sugar-phosphate backbones and nitrogenous bases paired in the center.

Recall that the sugar-phosphate backbone is held together by strong covalent bonds called phosphodiester bonds, which link the phosphate group of one nucleotide to the sugar of the next.

Understand that the two strands are held together by interactions between the nitrogenous bases from each strand, which pair specifically (A with T, and G with C).

Recognize that these base pairs are connected by hydrogen bonds, which are weaker than covalent bonds but strong enough to stabilize the double helix structure.

Conclude that the primary force holding the two strands together in the DNA double helix is the hydrogen bonding between complementary nitrogenous bases.