At the Isoelectric PH of a Tetrapeptide

question 89

Multiple Choice

At the isoelectric pH of a tetrapeptide:

• A) only the amino and carboxyl termini contribute charge.
• B) the amino and carboxyl termini are not charged.
• C) the total net charge is zero.
• D) there are four ionic charges.
• E) two internal amino acids of the tetrapeptide cannot have ionizable R groups.

---

Definitions:

Ester Linkages

Chemical bonds formed between an acid and an alcohol with the elimination of water, commonly found in fats and biological molecules like DNA.

Peptidoglycans

A polymer consisting of sugars and amino acids that forms a mesh-like layer outside the plasma membrane of most bacteria, providing structural support and shape.

Archaea

One of the two prokaryotic domains. The absence of peptidoglycan in their cell walls sets them apart from the bacteria. Compare with bacteria.

70S Ribosomes

Ribosomes typical in prokaryotes and mitochondria, involved in the synthesis of proteins, comprised of a 50S and a 30S subunit.