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

3. Energy & Cell Processes

DNA Repair

Anatomy & Physiology

3. Energy & Cell Processes

DNA Repair

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Problem 8

Textbook Question

What aspect of DNA structure makes it possible for the proteins of nucleotide excision repair to recognize many different types of DNA damage? (c) the energy differences between correct and incorrect base pairs

Verified step by step guidance

Understand that DNA structure is a double helix composed of two strands running in opposite directions, with base pairs (adenine-thymine and guanine-cytosine) held together by hydrogen bonds.

Recognize that nucleotide excision repair (NER) is a DNA repair mechanism that identifies and removes damaged DNA segments, particularly those with bulky adducts or distortions in the helix.

Consider that the proteins involved in NER can detect structural abnormalities in the DNA helix, such as kinks or bulges, which are often caused by incorrect or damaged base pairing.

Acknowledge that the energy differences between correct and incorrect base pairs can lead to structural changes in the DNA helix, making it easier for repair proteins to identify and bind to the damaged site.

Conclude that the ability of NER proteins to recognize a wide range of DNA damage is largely due to their capacity to detect these structural distortions, rather than relying solely on energy differences between base pairs.

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Key Concepts

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

DNA Structure

DNA is composed of two strands forming a double helix, with nucleotides containing a sugar, phosphate, and a nitrogenous base. The specific pairing of bases (adenine with thymine, and cytosine with guanine) allows for the formation of a stable structure. This arrangement is crucial for the recognition of distortions or damages in the DNA, as proteins involved in repair can identify alterations in the helical structure.

Nucleotide Excision Repair (NER)

Nucleotide excision repair is a cellular mechanism that identifies and removes damaged DNA segments. It involves several proteins that recognize distortions in the DNA helix caused by various types of damage, such as UV-induced lesions. The ability of NER proteins to recognize different types of damage is linked to their interaction with the DNA structure, allowing them to distinguish between normal and abnormal configurations.

Base Pairing Energy Differences

The energy differences between correct and incorrect base pairs play a significant role in DNA stability and repair. Correct base pairs have optimal hydrogen bonding and stacking interactions, while mismatched pairs exhibit destabilizing energy states. This energy disparity aids repair proteins in recognizing and correcting errors, as they can detect the less stable configurations associated with damaged or mismatched bases.