Table of contents

1. Introduction to Biochemistry4h 34m
2. Water3h 23m
3. Amino Acids8h 10m
4. Protein Structure10h 4m
5. Protein Techniques14h 5m
6. Enzymes and Enzyme Kinetics13h 38m
7. Enzyme Inhibition and Regulation 8h 42m
8. Protein Function 9h 41m
9. Carbohydrates7h 49m
10. Lipids5h 49m
11. Biological Membranes and Transport 6h 37m
12. Biosignaling9h 45m
Review 1: Nucleic Acids, Lipids, & Membranes2h 47m
Review 2: Biosignaling, Glycolysis, Gluconeogenesis, & PP-Pathway3h 12m
Review 3: Pyruvate & Fatty Acid Oxidation, Citric Acid Cycle, & Glycogen Metabolism2h 26m
Review 4: Amino Acid Oxidation, Oxidative Phosphorylation, & Photophosphorylation1h 48m

3. Amino Acids

Amino Acid Groups

Biochemistry

3. Amino Acids

Amino Acid Groups

Previous problemNext problem

Struggling with Biochemistry?

Join thousands of students who trust us to help them ace their exams!Watch the first video

Multiple Choice

Which of the following are purine bases?

Cytosine and thymine

Uracil and cytosine

Thymine and uracil

Adenine and guanine

Previous problemNext problem

Verified step by step guidance

Understand the classification of nitrogenous bases: Nitrogenous bases are divided into two categories, purines and pyrimidines. Purines have a double-ring structure, while pyrimidines have a single-ring structure.

Recall the purine bases: In biochemistry, the purine bases are adenine (A) and guanine (G). These are found in both DNA and RNA.

Recall the pyrimidine bases: Pyrimidine bases include cytosine (C), thymine (T), and uracil (U). Thymine is found in DNA, while uracil is found in RNA.

Analyze the options provided: Cytosine and thymine, uracil and cytosine, and thymine and uracil are all pyrimidine bases, as they have single-ring structures. Adenine and guanine are purine bases, as they have double-ring structures.

Conclude the correct answer: Based on the structural classification, adenine and guanine are the purine bases, as stated in the problem.