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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

For the eukaryotic DNA sequence shown below, which of the following correctly describes the directionality of the two strands in a double helix?

The two strands have random orientation with respect to each other.

Both strands run parallel to each other, oriented 5' to 3'.

Both strands run parallel to each other, oriented 3' to 5'.

The two strands run antiparallel to each other, with one strand oriented 5' to 3' and the other 3' to 5'.

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Verified step by step guidance

Recall that DNA strands in a double helix have directionality, meaning each strand has a 5' end and a 3' end based on the carbon numbering in the sugar backbone.

Understand that in a double-stranded DNA molecule, the two strands are complementary and run in opposite directions, a feature known as antiparallel orientation.

Recognize that one strand runs from the 5' end to the 3' end, while the complementary strand runs from the 3' end to the 5' end, allowing proper base pairing and the formation of hydrogen bonds.

Eliminate options that suggest random orientation or parallel strands running in the same direction, as these do not support the stable structure of the DNA double helix.

Conclude that the correct description is that the two strands run antiparallel to each other, with one strand oriented 5' to 3' and the other 3' to 5'.