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

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Multiple Choice

In humans, eggs and sperm each contain 23 chromosomes. Which of the following best describes the composition of sex chromosomes in these gametes?

Eggs always contain one X chromosome; sperm contain either an X or a Y chromosome.

Eggs and sperm both contain either an X or a Y chromosome at random.

Both eggs and sperm always contain one X chromosome.

Eggs can contain either an X or a Y chromosome; sperm always contain one X chromosome.

Verified step by step guidance

Recall that human somatic cells have 46 chromosomes, including 2 sex chromosomes (XX for females and XY for males).

Understand that gametes (eggs and sperm) are formed through meiosis, which halves the chromosome number to 23, including one sex chromosome.

Recognize that in females (XX), all eggs receive one X chromosome because both sex chromosomes are X.

Recognize that in males (XY), sperm can receive either an X or a Y chromosome, since males have one of each sex chromosome.

Conclude that eggs always contain one X chromosome, while sperm contain either an X or a Y chromosome, which determines the sex of the offspring.

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