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

Zwitterion

Biochemistry

3. Amino Acids

Zwitterion

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 shows the proper structure of Leu at physiological pH?

Previous problemNext problem

Verified step by step guidance

Identify the structure of leucine (Leu), which is an amino acid with the side chain isobutyl group: (CH2-CH-(CH3)2).

At physiological pH (around 7.4), amino acids exist in their zwitterionic form. This means the amino group (-NH2) is protonated to form -NH3^+ and the carboxyl group (-COOH) is deprotonated to form -COO^-.

Examine each provided structure to determine which one has the correct zwitterionic form of leucine. Look for the presence of -NH3^+ and -COO^- groups.

Check the side chain of each structure to ensure it matches the isobutyl group of leucine: (CH2-CH-(CH3)2).

Select the structure that correctly represents leucine at physiological pH, with both the zwitterionic form and the correct side chain.