Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

2. Cell Chemistry & Cell Components

Isotopes

Anatomy & Physiology

2. Cell Chemistry & Cell Components

Isotopes

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Multiple Choice

Which of the following statements about Barr bodies is true?

Barr bodies are active X chromosomes that express genes.

Barr bodies are present in all male mammalian cells.

Barr bodies are formed by the inactivation of one X chromosome in female mammals.

Barr bodies are found in the cytoplasm of cells.

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Verified step by step guidance

Understand the concept of Barr bodies: Barr bodies are condensed, inactive X chromosomes found in female mammals. They are a mechanism of dosage compensation to ensure that females, with two X chromosomes, do not have double the gene expression compared to males, who have one X chromosome.

Recognize that Barr bodies are not active X chromosomes. Instead, they represent the inactivated X chromosome, which does not express genes.

Identify that Barr bodies are not present in male mammalian cells. Males typically have one X and one Y chromosome, so there is no need for X chromosome inactivation.

Clarify that Barr bodies are located in the nucleus of cells, not the cytoplasm. They are visible as a dense, dark-staining spot within the nucleus during interphase.

Conclude that the correct statement is: Barr bodies are formed by the inactivation of one X chromosome in female mammals, ensuring balanced gene expression between males and females.