Questions Dr. Hafez Could Ask
Call Kai
Learn
Practice Test
Spaced Repetition
Match
Flashcards
Knowt Play1/94
There's no tags or description
Looks like no tags are added yet.
Name | Mastery | Learn | Test | Matching | Spaced | Call with Kai |
|---|
No analytics yet
Send a link to your students to track their progress
95 Terms
Why can red blood cells only produce ATP through glycolysis?
they lack mitochondria
Why can red blood cells not perform the TCA cycle or electron transport chain?
they lack mitochondria
What is the final product of glycolysis in red blood cells?
lactate
Why must pyruvate be converted to lactate during anaerobic glycolysis?
to regenerate NAD+ for glycolysis
Which enzyme deficiency commonly causes hemolytic anemia due to reduced ATP in RBCs?
pyruvate kinase deficiency
Which ETC complexes pump protons across the inner mitochondrial membrane?
Complex I, III, IV
Which ETC complex does NOT pump protons?
Complex II
What is the name of Complex II in the electron transport chain?
succinate dehydrogenase
What molecule carries electrons from Complex I and II to Complex III?
CoQ (ubiquinone)
What molecule carries electrons from Complex III to Complex IV?
cytochrome c
Which enzyme catalyzes the rate-limiting step of glycolysis?
PFK-1
Which enzyme bypasses the PFK-1 step in gluconeogenesis?
fructose-1,6-bisphosphatase
How does ATP regulate PFK-1 activity?
ATP inhibits PFK-1
Which molecule strongly activates PFK-1 and stimulates glycolysis?
fructose-2,6-bisphosphate
How does fructose-2,6-bisphosphate affect gluconeogenesis?
it inhibits fructose-1,6-bisphosphatase
Which enzyme catalyzes the rate-limiting step of fatty acid synthesis?
acetyl CoA carboxylase
What reaction does acetyl CoA carboxylase catalyze?
acetyl CoA to malonyl CoA
Which molecule activates acetyl CoA carboxylase?
citrate
Which enzyme inhibits acetyl CoA carboxylase through phosphorylation?
AMPK
Which hormone inhibits acetyl CoA carboxylase activity?
glucagon
Why must long-chain fatty acids use the carnitine shuttle to enter mitochondria?
the inner mitochondrial membrane is impermeable to fatty acyl CoA
Which enzyme transfers fatty acids to carnitine to begin mitochondrial transport?
carnitine acyltransferase I (CPT I)
Which enzyme regenerates fatty acyl CoA inside the mitochondrial matrix?
carnitine acyltransferase II (CPT II)
Which metabolic pathway is active in the fed state?
glycolysis
Which metabolic pathway is active during fasting?
gluconeogenesis
What are the two main products formed when triglycerides undergo catabolism?
free fatty acids, glycerol
What molecules are produced when proteins are degraded during catabolism?
amino acids
What molecule is produced when fatty acids are broken down during beta-oxidation and enters the TCA cycle?
acetyl CoA
What is the main purpose of acetyl CoA generated during catabolism?
generate ATP
What is the first stage of catabolism of macromolecules?
hydrolysis of complex molecules
What two processes characterize catabolic reactions?
hydrolysis of complex molecules, generation of ATP
What is the final product of glycolysis under aerobic conditions?
pyruvate
What is the final product of glycolysis under anaerobic conditions?
lactate
Why is glucose converted to glucose-6-phosphate immediately after entering a cell?
to trap glucose inside the cell
Which enzyme catalyzes the conversion of glucose to glucose-6-phosphate?
hexokinase
Which enzyme catalyzes the rate-limiting step of glycolysis?
PFK-1
What reaction does PFK-1 catalyze in glycolysis?
fructose-6-phosphate to fructose-1,6-bisphosphate
How do high ATP levels affect glycolysis?
inhibit PFK-1 and inhibit glycolysis
Which molecule activates PFK-1 and stimulates glycolysis?
fructose-2,6-bisphosphate
How does a carbohydrate-rich meal affect glycolysis?
activates PFK-1 and increases glycolysis
Which enzyme catalyzes the conversion of phosphoenolpyruvate to pyruvate?
pyruvate kinase
What condition can result from pyruvate kinase deficiency?
hemolytic anemia
Why does pyruvate kinase deficiency particularly affect red blood cells?
RBCs rely entirely on glycolysis for ATP
Which enzyme converts pyruvate to oxaloacetate during gluconeogenesis?
pyruvate carboxylase
Why do muscles experience soreness after intense exercise?
lactate accumulation lowers muscle pH
What molecule is the main substrate that enters the TCA cycle?
acetyl CoA
Where does the TCA cycle occur in the cell?
mitochondrial matrix
What metabolic problem results from pyruvate dehydrogenase complex deficiency?
lactic acidosis
Which TCA enzyme converts isocitrate to alpha-ketoglutarate?
isocitrate dehydrogenase
What reduced coenzyme is produced during the isocitrate to alpha-ketoglutarate reaction?
NADH
Where is the electron transport chain located?
inner mitochondrial membrane
Which ETC complexes pump protons across the inner mitochondrial membrane?
Complex I, III, IV
Which ETC complex does NOT pump protons?
Complex II
What is the name of Complex II of the electron transport chain?
succinate dehydrogenase
What is the function of Complex II?
transfer electrons from FADH2 to CoQ
Which molecule carries electrons from Complex I and II to Complex III?
CoQ (ubiquinone)
Which molecule carries electrons from Complex III to Complex IV?
cytochrome c
How many ATP are generated from oxidation of one NADH in the ETC according to classical calculations?
3 ATP
Which metabolites can serve as precursors for gluconeogenesis?
lactate, glycerol
Which enzyme converts fructose-1,6-bisphosphate to fructose-6-phosphate in gluconeogenesis?
fructose-1,6-bisphosphatase
What happens to glycerol released from triglyceride breakdown?
it is used for gluconeogenesis in the liver
Why must acetyl CoA be converted to citrate to leave the mitochondria during fatty acid synthesis?
acetyl CoA cannot cross the inner mitochondrial membrane
Which enzyme catalyzes the rate-limiting step of fatty acid synthesis?
acetyl CoA carboxylase
What reaction does acetyl CoA carboxylase catalyze?
acetyl CoA to malonyl CoA
Which molecule activates acetyl CoA carboxylase?
citrate
Which fatty acid inhibits acetyl CoA carboxylase?
palmitate
Which signaling pathways inhibit acetyl CoA carboxylase?
AMPK, glucagon
Which hormones activate lipolysis?
glucagon, epinephrine
Which intracellular signaling molecules stimulate lipolysis?
cAMP, PKA
What are the two major products of lipolysis?
free fatty acids, glycerol
Where does glycerol released from lipolysis primarily go?
liver
Into which glycolytic intermediate can glycerol be converted?
DHAP
How are fatty acids broken down to produce acetyl CoA?
beta-oxidation
What transport system allows long-chain fatty acids to enter mitochondria?
carnitine shuttle
What intermediate is formed when fatty acids bind carnitine?
acyl-carnitine
What molecules are produced during each cycle of beta-oxidation?
one acetyl CoA, one FADH2
What is the classical ATP yield from beta-oxidation of palmitate?
129 ATP
Which metabolic processes increase during prolonged fasting?
lipolysis, ketogenesis
Which tissues can utilize ketone bodies for energy?
brain, skeletal muscle
Why can red blood cells not utilize ketone bodies?
they lack mitochondria