Table of contents

1. Matter and Measurements4h 31m
2. Atoms and the Periodic Table5h 23m
3. Ionic Compounds2h 18m
4. Molecular Compounds2h 18m
5. Classification & Balancing of Chemical Reactions3h 17m
6. Chemical Reactions & Quantities2h 27m
7. Energy, Rate and Equilibrium3h 46m
8. Gases, Liquids and Solids3h 25m
9. Solutions4h 10m
10. Acids and Bases3h 29m
11. Nuclear Chemistry56m
BONUS: Lab Techniques and Procedures1h 38m
BONUS: Mathematical Operations and Functions47m
12. Introduction to Organic Chemistry1h 34m
13. Alkenes, Alkynes, and Aromatic Compounds2h 12m
14. Compounds with Oxygen or Sulfur1h 6m
15. Aldehydes and Ketones1h 1m
16. Carboxylic Acids and Their Derivatives1h 11m
17. Amines39m
18. Amino Acids and Proteins1h 51m
19. Enzymes1h 37m
20. Carbohydrates1h 41m
21. The Generation of Biochemical Energy2h 8m
22. Carbohydrate Metabolism2h 22m
23. Lipids2h 26m
24. Lipid Metabolism1h 45m
25. Protein and Amino Acid Metabolism1h 37m
26. Nucleic Acids and Protein Synthesis2h 54m

26. Nucleic Acids and Protein Synthesis

Nitrogenous Bases

GOB Chemistry

26. Nucleic Acids and Protein Synthesis

Nitrogenous Bases

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2:27 minutes

Problem 96

Textbook Question

How do the bases cytosine and uracil differ?

Verified step by step guidance

Understand that cytosine and uracil are nitrogenous bases found in nucleic acids. Cytosine is present in both DNA and RNA, while uracil is found only in RNA.

Recognize that cytosine is a pyrimidine base with the chemical formula C₄H₅N₃O, while uracil is also a pyrimidine base but has the chemical formula C₄H₄N₂O₂.

Note the structural difference: Cytosine contains an amine group (-NH₂) attached to its ring structure, whereas uracil lacks this amine group and instead has a ketone group (=O) at the same position.

Understand the functional implications: Cytosine can form three hydrogen bonds with guanine in DNA and RNA, while uracil pairs with adenine in RNA through two hydrogen bonds.

Summarize the key difference: Cytosine has an amine group, making it more chemically reactive, while uracil has a simpler structure with a ketone group, reflecting its role in RNA instead of DNA.

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Key Concepts

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

Nucleotide Structure

Nucleotides are the building blocks of nucleic acids, consisting of a sugar, a phosphate group, and a nitrogenous base. Cytosine and uracil are both nitrogenous bases, but they differ in their chemical structure. Cytosine is a pyrimidine base with an amine group, while uracil lacks this amine group, which influences their roles in RNA and DNA.

Base Pairing

Base pairing is a fundamental concept in molecular biology that describes how nitrogenous bases pair with each other in nucleic acids. In DNA, cytosine pairs with guanine, while uracil, which is found in RNA, pairs with adenine. Understanding these pairing rules is essential for grasping how genetic information is stored and transmitted.

Function in Nucleic Acids

Cytosine and uracil play distinct roles in nucleic acids. Cytosine is found in both DNA and RNA, contributing to the stability and structure of DNA, while uracil is primarily found in RNA, where it participates in protein synthesis. The presence of uracil instead of thymine in RNA is a key difference that affects the overall function and stability of the genetic material.