Question

Which substances can cross the mitochondrial membrane without the aid of carnitine or the CPT system?

1) Fatty acids
2) Glucose
3) Amino acids
4) Nucleotides

Answer 1

Glucose, amino acids, and nucleotides can cross the mitochondrial membrane without the aid of carnitine or the CPT system, unlike fatty acids that require it.

Step-by-step explanation:

The substances that can cross the mitochondrial membrane without the aid of carnitine or the CPT system include glucose, amino acids, and nucleotides. Fatty acids, in contrast, require conversion to fatty acyl carnitine by carnitine acyltransferase I for transport into the mitochondrial matrix. Once inside, fatty acyl carnitine is converted back to fatty acyl-CoA by carnitine acyltransferase II for further fatty acid oxidation. Glucose and amino acids can enter the mitochondria via specific transport proteins, and nucleotides typically pass through nucleotide translocase. Unlike fatty acids, these molecules do not require the carnitine shuttle for mitochondrial entry.