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

Sex Chromosome

Genetics

3. Extensions to Mendelian Inheritance

Sex Chromosome

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Multiple Choice

What is the genetic makeup (karyotype) of an individual with Jacob's syndrome?

45,X

47,XXX

47,XXY

47,XYY

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Verified step by step guidance

Understand that a karyotype describes the number and appearance of chromosomes in the nucleus of a cell, including the sex chromosomes.

Recall that Jacob's syndrome is a condition involving an extra Y chromosome in males, so the individual has two Y chromosomes and one X chromosome.

Write the karyotype notation by indicating the total number of chromosomes followed by the sex chromosome composition. Since humans normally have 46 chromosomes, an extra Y chromosome means 47 chromosomes total.

Express the karyotype as $47,XYY$, where 47 is the total chromosome count, and XYY indicates one X chromosome and two Y chromosomes.

Compare this to other karyotypes: $45,X$ is Turner syndrome (missing one sex chromosome), $47,XXX$ is Triple X syndrome (extra X chromosome in females), and $47,XXY$ is Klinefelter syndrome (extra X chromosome in males).