Question

Suppose an assassin uses abrin, a translation inhibitor, to poison her victim. Place the events in chronological order, starting from the poisoning and ending with the death of the victim.
Arbin is absorbed into the blood and enters the body's cells.
Arbin inactivates the 28S rRNA in the large subunit of the ribosome.
Arbin binds to ribosomes in the cytoplasm.
Ribosomes are unable to add new amino acids to polypeptides.
Multiple organ systems fail.
Protein synthesis halts in many tissues.

Answer 1

Answer:

The events in chronological order are:

1. Abrin is absorbed into the blood and enters the body's cells
2. Abrin binds to ribosomes in the cytoplasm
3. Abrin inactivates the 28S rRNA in the large subunit of the ribosome.
4. Ribosomes are unable to add new amino acids to polypeptides
5. Protein synthesis halts in many tissues
6. Multiple organ systems fail
7. Victim dies

Explanation:

Abrin is a toxic protein obtained from the seeds of Abrus precatorius, it is highly toxic, with an estimated human fatal dose of 0.1-1 microgram/kg, and causes death after accidental and intentional poisoning.

When ingested the abrin would enter the victim's body and travel through the blood and eventually enter a cell's cytoplasm (abrin is absorbed into the blood and enters the body's cells). Once there it would interact with the ribosomes and reacts with them on a molecular level (peptide bond catalytic enzyme) (abrin binds to ribosomes in the cytoplasm), which results in the ribosome exhibiting its toxic response to abrin (abrin inactivates the 28S rRNA in the large subunit of the ribosome). As a result of the ribosome reacting to abrin (ribosomes are unable to add new amino acids to polypeptides), protein synthesis within that cell is affected (protein synthesis halts in many tissues). Once multiple cells are affected by abrin the organ will exhibit its toxic response (multiple organ systems fail), and the victim would die.