Table of contents

1. Introduction to Biology2h 42m
2. Chemistry3h 37m
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 6m
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 53m
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 49m
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

Introduction to DNA Replication

General Biology

14. DNA Synthesis

Introduction to DNA Replication

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Multiple Choice

During the first step in DNA replication, DNA is unwound or 'unzipped' by the enzyme:

Ligase

Primase

DNA polymerase

Helicase

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Verified step by step guidance

Understand the process of DNA replication: DNA replication is the process by which a DNA molecule is copied to produce two identical DNA molecules. It involves several enzymes, each with a specific role.

Identify the role of helicase: Helicase is the enzyme responsible for unwinding or 'unzipping' the double-stranded DNA by breaking the hydrogen bonds between complementary base pairs (A-T and G-C). This creates two single strands that serve as templates for replication.

Differentiate the roles of other enzymes: Ligase is responsible for joining Okazaki fragments on the lagging strand. Primase synthesizes RNA primers to initiate DNA synthesis. DNA polymerase adds nucleotides to the growing DNA strand but does not unwind the DNA.

Focus on the first step of replication: The first step in DNA replication is the unwinding of the DNA double helix, which is specifically carried out by helicase. This step is crucial to expose the template strands for replication.

Conclude that helicase is the correct enzyme for the first step: Based on the roles of the enzymes, helicase is the enzyme that performs the unzipping of DNA during the initial stage of replication.