Questions and Answers
What does DNA stand for?
DeoxyriboNucleic Acid
Why is DNA important to living things?
DNA is important because it contains genetic instructions for development and function.
What is the overall structure of DNA called?
DNA structure
What are the monomer and polymer of DNA?
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What are the three parts of a nucleotide?
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What are the four nitrogenous bases in DNA?
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What is the backbone of DNA made of?
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What holds the two strands of DNA together?
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What does it mean that the two strands of DNA are complementary?
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What are the two categories of nitrogenous bases in DNA?
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How many rings does a pyrimidine have and which bases are pyrimidines?
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How many rings does a purine have and which bases are purines?
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Which base pairs with which in DNA?
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How many hydrogen bonds form between each base pair?
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What are the major and minor grooves in DNA?
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How many nucleotides are in one turn of DNA?
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Study Notes
DNA Overview
- DNA stands for DeoxyriboNucleic Acid, a vital molecule for the genetic instructions of living organisms.
- It plays a crucial role in the long-term storage of genetic information necessary for the development and function of all life forms, including some viruses.
DNA Structure
- DNA consists of nucleotides which comprise a phosphate group, a sugar (deoxyribose), and one of four nitrogen bases: adenine (A), thymine (T), guanine (G), and cytosine (C).
- Nucleotides are the monomer units of DNA, while the polymer form is a "polynucleotide."
Nucleotide Composition
- A nucleotide consists of a nitrogenous base, a deoxyribose sugar, and a phosphate group connecting to the sugar's 5' side.
- The four nitrogenous bases are categorized as:
- Purines: Adenine (A) and Guanine (G)
- Pyrimidines: Cytosine (C) and Thymine (T)
DNA Backbone and Bonds
- The DNA backbone is formed by alternating phosphate groups and deoxyribose sugars, linked via phosphodiester bonds.
- Hydrogen bonds hold the two DNA strands together, forming between complementary base pairs (A-T and C-G).
Base Pairing Rules
- Adenine pairs with Thymine (2 hydrogen bonds).
- Cytosine pairs with Guanine (3 hydrogen bonds).
- The complementary nature of strands is essential for DNA replication and function.
Nucleotide Arrangement
- Pyrimidines have a single six-membered nitrogen-containing ring.
- Purines have a fused six-membered and five-membered ring structure.
DNA Helix and Enzymatic Interaction
- The DNA helix has major and minor grooves; the major groove is wider and more accessible than the minor groove.
- This structural difference allows certain proteins to bind to DNA more easily in the major groove for purposes like transcription and replication.
Structural Characteristics
- In B-DNA, the most commonly observed DNA form, there are approximately 10 to 10.5 base pairs per helical turn, translating to about 20 to 21 nucleotides per turn.
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Description
Explore the fundamental aspects of DNA with this quiz on its structure and significance. You'll learn about its full name, role in living organisms, and key characteristics. Test your knowledge and deepen your understanding of genetic material.
