Table of contents

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

3. Extensions to Mendelian Inheritance

Understanding Independent Assortment

Genetics

3. Extensions to Mendelian Inheritance

Understanding Independent Assortment

Previous problemNext problem

Struggling with Genetics?

Join thousands of students who trust us to help them ace their exams!Watch the first video

Multiple Choice

If 35% of an organism's DNA is thymine, what is the percentage of guanine?

20%

30%

15%

35%

Previous problemNext problem

Verified step by step guidance

Recall Chargaff's rules, which state that in double-stranded DNA, the amount of adenine (A) equals thymine (T), and the amount of guanine (G) equals cytosine (C). This means $\%A = \%T$ and $\%G = \%C$.

Given that thymine (T) makes up 35% of the DNA, adenine (A) must also be 35% because $\%A = \%T$.

Calculate the combined percentage of adenine and thymine: $\%A + \%T = 35\% + 35\% = 70\%$.

Since the total percentage of all four bases must equal 100%, subtract the combined A and T percentage from 100% to find the combined percentage of guanine and cytosine: $100\% - 70\% = 30\%$.

Because guanine and cytosine are present in equal amounts, divide the combined G and C percentage by 2 to find the percentage of guanine: $\%G = \frac{30\%}{2}$.