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

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Multiple Choice

How many standard amino acids are incorporated into proteins during translation in humans?

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Verified step by step guidance

Understand the context of the question: Translation is the process by which ribosomes synthesize proteins using mRNA as a template. During this process, amino acids are incorporated into the growing polypeptide chain.

Recall that standard amino acids are the building blocks of proteins. These are encoded by the genetic code and are universally used in protein synthesis across organisms.

Note that humans use 20 standard amino acids during translation. These amino acids are encoded by codons in the mRNA, which are recognized by tRNA molecules carrying the corresponding amino acids.

Consider the exceptions: Selenocysteine and pyrrolysine are sometimes referred to as the 21st and 22nd amino acids, but they are not universally incorporated into proteins. Selenocysteine is incorporated via a unique mechanism involving a specific mRNA sequence and additional factors.

Conclude that the correct answer depends on whether the question is asking about the universally recognized standard amino acids (20) or includes the rare cases of selenocysteine and pyrrolysine (21 or 22).