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

Given that a subunit of a protein is an amino acid, which of the following statements is true?

Amino acids are linked by peptide bonds to form proteins.

Amino acids are the subunits of nucleic acids.

Amino acids cannot exist in zwitterionic form at physiological pH.

Amino acids are composed solely of carbon and hydrogen atoms.

Previous problemNext problem

Verified step by step guidance

Step 1: Begin by understanding the structure and function of amino acids. Amino acids are organic molecules that serve as the building blocks of proteins. They consist of a central carbon atom (α-carbon) bonded to an amino group (-NH₂), a carboxyl group (-COOH), a hydrogen atom, and a variable side chain (R group).

Step 2: Clarify the concept of peptide bonds. Peptide bonds are covalent bonds formed between the carboxyl group of one amino acid and the amino group of another amino acid during a condensation reaction, resulting in the release of a water molecule. This process links amino acids together to form polypeptides and proteins.

Step 3: Address the zwitterionic form of amino acids. At physiological pH (~7.4), amino acids typically exist in a zwitterionic form, where the amino group is protonated (-NH₃⁺) and the carboxyl group is deprotonated (-COO⁻). This dual charge state is a key property of amino acids.

Step 4: Examine the composition of amino acids. Amino acids are not composed solely of carbon and hydrogen atoms; they also contain nitrogen (in the amino group), oxygen (in the carboxyl group), and sometimes sulfur or other elements in the side chain.

Step 5: Conclude by identifying the correct statement. Based on the above clarifications, the correct statement is: 'Amino acids are linked by peptide bonds to form proteins.' This reflects the fundamental role of amino acids in protein synthesis.