Table of contents

1. Introduction to Biology2h 42m
2. Chemistry3h 40m
3. Water1h 26m
4. Biomolecules2h 23m
5. Cell Components2h 26m
6. The Membrane2h 31m
7. Energy and Metabolism2h 0m
8. Respiration2h 40m
9. Photosynthesis2h 49m
10. Cell Signaling59m
11. Cell Division2h 47m
12. Meiosis2h 0m
13. Mendelian Genetics4h 44m
14. DNA Synthesis2h 27m
15. Gene Expression3h 20m
16. Regulation of Expression3h 31m
17. Viruses37m
- Viruses
  37m
18. Biotechnology2h 58m
19. Genomics17m
- Genomes
  17m
20. Development1h 5m
21. Evolution3h 1m
22. Evolution of Populations3h 52m
23. Speciation1h 37m
24. History of Life on Earth2h 6m
25. Phylogeny2h 31m
26. Prokaryotes4h 59m
27. Protists1h 12m
28. Plants1h 22m
29. Fungi36m
- Fungi
  19m
- Fungi Reproduction
  17m
30. Overview of Animals34m
- Overview of Animals
  34m
31. Invertebrates1h 2m
32. Vertebrates50m
33. Plant Anatomy1h 3m
34. Vascular Plant Transport1h 2m
- Water Potential
  1h 2m
35. Soil37m
- Soil and Nutrients
  20m
- Nitrogen Fixation
  16m
36. Plant Reproduction47m
- Flowers
  33m
- Seeds
  14m
37. Plant Sensation and Response1h 9m
38. Animal Form and Function1h 19m
39. Digestive System1h 10m
- Digestion
  1h 3m
- Blood Sugar Homeostasis
  7m
40. Circulatory System1h 57m
41. Immune System1h 12m
42. Osmoregulation and Excretion50m
- Osmoregulation and Excretion
  50m
43. Endocrine System1h 4m
- Endocrine System
  1h 4m
44. Animal Reproduction1h 2m
- Animal Reproduction
  1h 2m
45. Nervous System1h 55m
- Neurons and Action Potentials
  1h 8m
- Central and Peripheral Nervous System
  46m
46. Sensory Systems46m
- Sensory System
  46m
47. Muscle Systems23m
- Musculoskeletal System
  23m
48. Ecology3h 11m
49. Animal Behavior28m
- Animal Behavior
  28m
50. Population Ecology3h 41m
51. Community Ecology2h 46m
52. Ecosystems2h 36m
53. Conservation Biology24m
- Conservation Biology
  24m

14. DNA Synthesis

DNA Repair

General Biology

14. DNA Synthesis

DNA Repair

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0:43 minutes

Problem 8b`

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?
(b) the antiparallel orientation of strands in the double helix

Verified step by step guidance

Understand the structure of DNA: DNA is composed of two strands that form a double helix. Each strand is made up of nucleotides, which include a phosphate group, a sugar molecule (deoxyribose), and a nitrogenous base (adenine, thymine, cytosine, or guanine).

Recognize the antiparallel orientation: In the double helix, the two strands run in opposite directions, meaning one strand runs 5' to 3' and the other runs 3' to 5'. This orientation is crucial for the replication and repair processes.

Identify the role of nucleotide excision repair: This repair mechanism is responsible for detecting and removing damaged nucleotides, such as those caused by UV light or chemical exposure, and replacing them with the correct nucleotides.

Explore how proteins recognize DNA damage: Proteins involved in nucleotide excision repair can identify distortions in the DNA helix caused by damage. The antiparallel orientation allows these proteins to scan both strands effectively, recognizing a wide variety of damage types.

Consider the flexibility of the DNA structure: The double helix can undergo local unwinding or bending, which helps repair proteins access and recognize damaged sites. The antiparallel nature ensures that the repair machinery can operate efficiently across different types of damage.

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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 each strand consisting of nucleotides. The structure is stabilized by hydrogen bonds between complementary bases (adenine-thymine and guanine-cytosine). This configuration allows for the recognition and repair of damaged sites by repair proteins, as any deviation from the normal base pairing can be detected.

Antiparallel Orientation

The antiparallel orientation refers to the opposite directional alignment of the two DNA strands, where one strand runs 5' to 3' and the other 3' to 5'. This orientation is crucial for replication and repair processes, as it ensures that enzymes and repair proteins can access and interact with the DNA in a consistent manner, facilitating the recognition of structural anomalies.

Nucleotide Excision Repair

Nucleotide excision repair is a DNA repair mechanism that identifies and removes damaged nucleotides, particularly those causing distortions in the DNA helix. This process involves several proteins that scan the DNA for irregularities, excise the damaged section, and fill in the gap with the correct nucleotides, maintaining genomic integrity.