nmdcat.online
BIO NMDCAT Proteins
nmdcat.online June 29, 2026

The fundamental structural feature common to all standard amino acids found in proteins is the presence of

A. An amino group and a carboxyl group attached to the same α-carbon atom
✓
B. A sulfhydryl group and a hydroxyl group on the β-carbon
C. A purine ring and a phosphate group
D. An aromatic ring and a guanidinium group

📝 Explanation

All 20 standard amino acids (except proline, which is an imino acid) are α-amino acids. They contain a central α-carbon to which an amino group (-NH₂), a carboxyl group (-COOH), a hydrogen atom, and a variable R-group are attached.

📖 Additional Information

  • An amino group and a carboxyl group attached to the same α-carbon atom
  • A sulfhydryl group and a hydroxyl group on the β-carbon
  • A purine ring and a phosphate group
  • An aromatic ring and a guanidinium group

All 20 standard amino acids (except proline, which is an imino acid) are α-amino acids. They contain a central α-carbon to which an amino group (-NH₂), a carboxyl group (-COOH), a hydrogen atom, and a variable R-group are attached.

🔗 Share This Question

Facebook Twitter LinkedIn WhatsApp

🧭 Navigate Questions

Previous Question

Acylglycerols containing one fatty acid attached to glycerol are known as

Next Question

In living organisms, the classification of an amino acid as essential implies that it

Back to All Questions

🔗 Related MCQs

An increase in the incidence of ectopic pregnancies within a population can often be epidemiologically correlated with a prior increase in the prevalence of which sexually transmitted disease?
July 16, 2026
In the life cycle of Herpes Simplex Virus 2 (HSV-2), the virus travels along nerve fibers to reach the sensory ganglia. The cellular mechanism responsible for this retrograde transport utilizes:
July 16, 2026
A defining characteristic of the lesions associated with the secondary stage of syphilis is that they:
July 16, 2026
The causative agent of genital herpes, HSV-2, is enveloped. The biological significance of this viral envelope in the context of transmission is that it makes the virus:
July 16, 2026
The structural basis for the severe cardiovascular complications seen in tertiary syphilis, such as aortic aneurysms, is the chronic inflammation and destruction of:
July 16, 2026

Categories

View all →