PPA Exam 2 Questions with Complete Solutions (Latest 2025) The major inhibitory amino acid neurotransmitter in the mature CNS - Correct Answers ✅y-Aminobutyric acid
(GABA)
GABA Synthesis - Correct Answers ✅Derived by decarboxylation of glutamate by glutamic acid decarboxylase (GAD) Key enzyme and rate limiting step in the process Where is GABA most abundant? - Correct Answers ✅Brain, spinal cord, peripheral tissues (intestine, lung, etc) Smallest of the 20 alpha amino acids Uniquely achiral A precursor and building block for the construction of proteins, notably collagen Forms key step in biosynthesis of porphyrins and purines - Correct Answers ✅Glycine Glycine synthesis - Correct Answers ✅Biosynthesized from amino acid serine 1 / 3
PPA Exam 2 Questions with Complete Solutions (Latest 2025) Mostly catalyzed by the enzyme hydroxymethytransferase to produce glycine Also obtained from dietary protein Where is glycine highly abundant and what is it thought to be in this area? - Correct Answers ✅Spinal cord Major inhibitory neurotransmitter True or False?GABA and glycine are able to penetrate the blood-brain barrier or cross membranes unassisted - Correct Answers ✅False Reuptake of GABA and glycine - Correct Answers ✅4 GABA transporters found in neurons and glia Na+ and Cl- dependent GABA is co-transported with ions into cells to power process 2 / 3
PPA Exam 2 Questions with Complete Solutions (Latest 2025) Ions move down electrochemical gradient, so Na+ and Cl- enter cell with GABA Found in brain cell membranes high affinity for GABA - Correct Answers ✅Type 1 (GAT1) Mostly found in liver, kidneys and in meninges at low concentration - Correct Answers ✅Type 2 (GAT2) found in glial cells Terminates GABA signaling in neighboring synapse by uptake
- Correct Answers ✅Type 3 (GAT3)
- / 3
Ancient protein found in bacteria Mammalian version distributed w/GAT2 Low affinity for GABA