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

Nucleic Acids

Anatomy & Physiology

2. Cell Chemistry & Cell Components

Nucleic Acids

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3:09 minutes

Problem 8

Textbook Question

According to the RNA world model, a ribozyme would replicate by creating a double-stranded RNA intermediate. Would you expect the intermediate to have the same catalytic activity as the original ribozyme? Justify your answer with an explanation.

Verified step by step guidance

Step 1: Understand the RNA world model. The RNA world model is a hypothesis that suggests that in the early stages of life on Earth, RNA molecules played a crucial role in the evolution of life. This is because RNA is capable of both storing genetic information, like DNA, and catalyzing chemical reactions, like proteins.

Step 2: Understand what a ribozyme is. A ribozyme is an RNA molecule that can catalyze specific biochemical reactions, similar to the action of protein enzymes. The most common activity of natural ribozymes is the cleavage or ligation of RNA and DNA.

Step 3: Understand the replication process of a ribozyme. According to the RNA world model, a ribozyme would replicate by creating a double-stranded RNA intermediate. This process involves the ribozyme acting as a template for the synthesis of a complementary RNA strand.

Step 4: Consider the structure and function of the double-stranded RNA intermediate. The double-stranded RNA intermediate is a product of the replication process and is not itself a ribozyme. It is a double-stranded structure, which is not conducive to the catalytic activity that is characteristic of ribozymes. Ribozymes typically require a specific three-dimensional structure to perform their catalytic function, and this structure is not present in the double-stranded intermediate.

Step 5: Based on the above understanding, we can conclude that the double-stranded RNA intermediate would not have the same catalytic activity as the original ribozyme. This is because the structure of the intermediate is not conducive to catalytic activity, and the intermediate is not itself a ribozyme but a product of the replication process.

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Key Concepts

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

RNA World Hypothesis

The RNA World Hypothesis posits that early life forms relied on RNA for both genetic information storage and catalysis, before the evolution of DNA and proteins. This model suggests that ribozymes, RNA molecules with catalytic properties, played a crucial role in the origins of life by facilitating biochemical reactions necessary for replication and metabolism.

Ribozyme Functionality

Ribozymes are RNA molecules capable of catalyzing specific biochemical reactions, similar to protein enzymes. Their catalytic activity depends on their three-dimensional structure, which is determined by the sequence of nucleotides. When a ribozyme replicates, the resulting double-stranded RNA intermediate may not maintain the same structural conformation, potentially affecting its catalytic properties.

Catalytic Activity and Structure

Catalytic activity in biomolecules is closely linked to their structure, particularly the arrangement of functional groups that interact with substrates. In the case of ribozymes, if the double-stranded RNA intermediate does not fold into the correct conformation, it may lack the necessary active site for catalysis, leading to diminished or absent catalytic activity compared to the original ribozyme.