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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0:46 minutes

Problem 8a`

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?
(a) the polarity of each DNA strand

Verified step by step guidance

Understand the basic structure of DNA: DNA is composed of two strands forming a double helix, with each strand consisting of a sugar-phosphate backbone and nitrogenous bases (adenine, thymine, cytosine, and guanine) paired through hydrogen bonds.

Recognize the concept of DNA polarity: Each DNA strand has a directionality or polarity, defined by the orientation of the sugar-phosphate backbone. One end of the strand is the 5' end, and the other is the 3' end, which is crucial for various biological processes.

Explore nucleotide excision repair (NER): NER is a DNA repair mechanism that identifies and removes damaged nucleotides, replacing them with the correct ones. It is versatile and can recognize a wide range of DNA damage types, such as UV-induced thymine dimers and bulky adducts.

Identify how DNA structure aids NER: The regularity and uniformity of the DNA double helix allow repair proteins to detect distortions or irregularities in the structure, which often indicate damage. The polarity of the strands helps guide the repair process, ensuring the correct orientation for excision and synthesis.

Consider the role of DNA strand polarity in repair: The polarity of each strand ensures that the repair machinery can correctly identify the damaged site and orient the repair synthesis in the proper direction, maintaining the integrity of the genetic information.

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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 a sugar-phosphate backbone and nitrogenous bases. The specific pairing of bases (adenine with thymine, and cytosine with guanine) allows for the recognition and repair of mismatches or damage, as the structure is altered when errors occur.

Nucleotide Excision Repair

Nucleotide excision repair is a mechanism that identifies and removes damaged sections of DNA. It is versatile in recognizing various types of damage, such as bulky adducts or thymine dimers, by detecting distortions in the DNA helix, which are indicative of structural anomalies.

Polarity of DNA Strands

The polarity of DNA strands refers to the orientation of the sugar-phosphate backbone, with one strand running 5' to 3' and the other 3' to 5'. This antiparallel arrangement is crucial for replication and repair processes, as it ensures that enzymes can correctly identify and process the strands during repair.