Exam 1 2025 Flashcards
What is the function of GLUT1?
Transport glucose at a constant rate
Found in red blood cells and the blood-brain barrier
Where is GLUT2 primarily found?
Liver, pancreas, and kidney
Functions in glucose uptake and release, acting as a glucose sensor
What is the primary role of GLUT3?
High-affinity transporter for rapid glucose uptake
Predominantly in neurons
What type of glucose uptake does GLUT4 facilitate?
Insulin-dependent glucose uptake
Found in adipose tissue and muscle
What is the main function of GLUT5?
Transport of fructose
Primarily involved in the small intestine
What is the significance of glucose transporters?
Facilitate the passive transport of glucose across the cell membrane
Vary in affinity and capacity, matching the metabolic needs of different tissues
What syndrome is caused by GLUT1 deficiency?
GLUT1 Deficiency Syndrome
Leads to seizures, developmental delays, and motor dysfunction
What condition is associated with GLUT2 mutation?
Fanconi-Bickel Syndrome
Characterized by glycogen storage issues, hepatomegaly, and renal tubular dysfunction
What is linked to GLUT4 impairment?
Insulin resistance and Type 2 Diabetes
What is the primary function of the liver in glucose metabolism?
Central in glucose homeostasis, glycogen storage, and gluconeogenesis
What role does muscle play in glucose metabolism?
Glucose uptake and utilization for energy during contraction
What is the pancreas’s function in glucose regulation?
Sensing blood glucose levels and regulating insulin/glucagon secretion
Where does oxidative phosphorylation occur?
Mitochondria
What metabolic process occurs in the cytoplasm?
Glycolysis and initial steps of gluconeogenesis
What is the first intermediate in glycolysis?
Glucose
Which enzyme converts glucose to glucose-6-phosphate?
Hexokinase/Glucokinase
What is the enzyme that converts fructose-6-phosphate to fructose-1,6-bisphosphate?
Phosphofructokinase-1
What are the two products of aldolase in glycolysis?
Glyceraldehyde-3-phosphate and Dihydroxyacetone phosphate
What is generated during glycolysis?
Net 2 ATP and 2 NADH
What does gluconeogenesis consume per glucose molecule synthesized?
4 ATP, 2 GTP, and 2 NADH
What inhibits hexokinase/glucokinase?
Glucose-6-phosphate
What activates phosphofructokinase-1 (PFK-1)?
AMP
Inhibited by ATP and citrate
What activates pyruvate kinase?
Fructose-1,6-bisphosphate
Inhibited by ATP and alanine
What is the importance of lactic fermentation?
Allows for ATP generation under anaerobic conditions
What enzyme reduces pyruvate to lactate?
Lactate dehydrogenase
What are the symptoms of Pyruvate Dehydrogenase Deficiency?
Lactic acidosis and neurological symptoms
What pathway does galactose metabolism follow?
Galactose → Galactose-1-phosphate → UDP-Galactose → Glucose-1-phosphate
What deficiency causes galactosemia?
Deficiency in galactose-1-phosphate uridyltransferase
What are the symptoms of galactosemia?
Jaundice, hepatomegaly, and intellectual disability
What pathway does fructose metabolism follow?
Fructose → Fructose-1-phosphate → Glyceraldehyde and DHAP
What deficiency causes Hereditary Fructose Intolerance?
Deficiency in aldolase B
What are the symptoms of Hereditary Fructose Intolerance?
Hypoglycemia, vomiting, and liver damage after fructose ingestion
