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

6. Chromosomal Variation

Chromosomal Mutations: Aneuploidy

Genetics

6. Chromosomal Variation

Chromosomal Mutations: Aneuploidy

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Multiple Choice

Which of the following chromosomal events might result in a human zygote with 45 chromosomes?

Duplication of a chromosome segment during mitosis

Nondisjunction of a chromosome during meiosis leading to monosomy

Translocation between two nonhomologous chromosomes

Nondisjunction resulting in a gamete with two extra chromosomes

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Verified step by step guidance

Understand that a normal human zygote has 46 chromosomes, arranged in 23 pairs.

Recall that nondisjunction is the failure of chromosome pairs to separate properly during meiosis, which can lead to gametes with abnormal chromosome numbers.

Recognize that if nondisjunction occurs during meiosis and results in a gamete missing one chromosome (monosomy), when it fuses with a normal gamete, the resulting zygote will have 45 chromosomes.

Consider that duplication of a chromosome segment during mitosis does not change the total chromosome number, only the content of a chromosome.

Note that translocation rearranges parts between nonhomologous chromosomes but does not change the total chromosome count, and nondisjunction causing two extra chromosomes would result in 48 chromosomes, not 45.