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 Configuration

Biochemistry

3. Amino Acids

Amino Acid Configuration

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

At physiological pH (approximately 7.4), what is the net charge on the carboxyl terminal of amino acids in proteins?

Positive

Double positive

Negative

Neutral

Previous problemNext problem

Verified step by step guidance

Understand the structure of the carboxyl terminal group in amino acids. The carboxyl terminal consists of a carboxylic acid group (-COOH). At physiological pH, this group can lose a proton (H⁺), becoming negatively charged (-COO⁻).

Recall the concept of pKa. The pKa of the carboxylic acid group in amino acids is typically around 2-3, which is much lower than the physiological pH of 7.4. This means the carboxylic acid group will be deprotonated at physiological pH.

Analyze the charge state. When the carboxylic acid group loses a proton, it becomes negatively charged (-COO⁻). This is the typical state of the carboxyl terminal at physiological pH.

Compare the options provided. The correct answer must align with the charge state of the carboxyl terminal at physiological pH, which is negative.

Conclude that the net charge on the carboxyl terminal of amino acids in proteins at physiological pH is negative, based on the deprotonation of the carboxylic acid group.