Question

Before amino acids (the building blocks of proteins) can be catabolized, they must be converted to other substances that can enter the Krebs cycle by all of the following methods, except:

1) Transamination
2) Deamination
3) Decarboxylation
4) Oxidative phosphorylation

Answer 1

Before amino acids can be catabolized and enter the Krebs cycle, they must be converted to other substances through processes like transamination, deamination, and decarboxylation. Oxidative phosphorylation is not involved in this conversion. So, the correct answer is option 4.

Step-by-step explanation:

Before amino acids can enter the Krebs cycle for catabolism, they must be converted to other substances. These conversions include transamination, deamination, and decarboxylation. Transamination involves transferring an amino group from one molecule to another, while deamination removes the amino group from an amino acid. Decarboxylation removes a carboxyl group from the amino acid. Oxidative phosphorylation, on the other hand, is a process in cellular respiration that generates ATP. It is not directly involved in converting amino acids for entry into the Krebs cycle. So, the correct answer is option 4.