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

17. The Blood

Introduction To Blood

Anatomy & Physiology

17. The Blood

Introduction To Blood

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1:19 minutes

Problem 6

Textbook Question

A hemoglobin molecule is composed of:
(a) Two protein chains
(b) Three protein chains
(c) Four protein chains and nothing else
(d) Four protein chains and four heme groups
(e) Four heme groups but no protein

Verified step by step guidance

Step 1: Understand the structure of hemoglobin. Hemoglobin is a protein found in red blood cells responsible for oxygen transport. It is composed of both protein chains and heme groups.

Step 2: Recall that hemoglobin consists of four polypeptide chains (two alpha chains and two beta chains) which are the protein components of the molecule.

Step 3: Note that each polypeptide chain is associated with a heme group. A heme group contains an iron ion (Fe²⁺) that binds oxygen molecules.

Step 4: Eliminate incorrect options based on the structure of hemoglobin. For example, options (a), (b), and (e) are incorrect because they do not account for both protein chains and heme groups.

Step 5: Identify the correct answer as the option that includes both four protein chains and four heme groups, which accurately describes the composition of hemoglobin.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Structure of Hemoglobin

Hemoglobin is a complex protein found in red blood cells, primarily responsible for transporting oxygen. It consists of four polypeptide chains, typically two alpha and two beta chains, which form a quaternary structure. This arrangement allows hemoglobin to efficiently bind and release oxygen molecules.

Heme Groups

Each hemoglobin molecule contains four heme groups, which are iron-containing compounds that bind to oxygen. The heme groups are crucial for the oxygen-carrying capacity of hemoglobin, as they allow the protein to pick up oxygen in the lungs and release it in tissues. The presence of heme is essential for the functionality of hemoglobin.

Oxygen Transport Mechanism

The mechanism of oxygen transport by hemoglobin involves cooperative binding, where the binding of one oxygen molecule increases the affinity of the remaining sites for oxygen. This property enables hemoglobin to efficiently load oxygen in high-concentration environments, such as the lungs, and release it in low-concentration areas, like active tissues, ensuring effective oxygen delivery throughout the body.