WorksheetsExercise Metabolism and Cell Signaling Quiz
Total questions: 14
Worksheet time: 7mins
The 'crossover concept' in exercise metabolism refers to:
Switching from aerobic to anaerobic metabolism at VO2max
A shift from predominantly fat oxidation to predominantly carbohydrate oxidation with increasing intensity
The point at which lactate equals pyruvate concentration
The transition from type I to type II fiber recruitment only
At the same absolute workload, endurance-trained individuals generally exhibit a lower RER because of:
Higher reliance on amino acid oxidation
Greater fat oxidation and reduced carbohydrate reliance
Lower mitochondrial content
Reduced capillary density
Glycogen depletion during prolonged exercise most strongly contributes to fatigue by:
Blocking lipolysis in adipose tissue
Reducing the rate of carbohydrate-derived ATP resynthesis at higher intensities
Increasing blood pH
Preventing oxygen from binding hemoglobin
Which scenario most increases net lactate appearance in blood during incremental exercise?
Increased lactate clearance with unchanged production
Unchanged production with increased clearance
Production rises faster than clearance capacity
Clearance rises faster than production
The fast component of EPOC is most closely related to:
Resynthesis of phosphocreatine and re-oxygenation of myoglobin/hemoglobin
Muscle fiber hypertrophy
Long-term increases in mitochondrial enzymes
Glycogen supercompensation
The 'fatmax' intensity is best defined as the exercise intensity at which:
Total fat mass decreases fastest
Absolute rate of fat oxidation is maximal
RER equals 0.85 exactly
Lactate begins to accumulate
During prolonged endurance exercise, a rise in circulating free fatty acids (FFA) typically causes:
Increased PDH activity and carbohydrate oxidation
Decreased carbohydrate oxidation via Randle cycle mechanisms
Complete inhibition of beta-oxidation
Immediate depletion of liver glycogen
Which metabolic pathway is primarily responsible for producing glucose from lactate during recovery?
Glycogenolysis
Cori cycle (hepatic gluconeogenesis)
Pentose phosphate pathway
Ketogenesis
Ammonia accumulation during high-intensity exercise is most directly linked to:
Deamination during amino acid transamination only
ATP breakdown and AMP deamination (purine nucleotide cycle)
Beta-oxidation of fatty acids
Lactate oxidation in mitochondria
The carnitine shuttle is essential for:
Transport of glucose into muscle fibers
Transport of long-chain fatty acyl-CoA into the mitochondrial matrix
Export of lactate from muscle to blood
Transport of pyruvate into mitochondria
Which signaling kinase is a key energy sensor activated by increases in AMP/ATP ratio during exercise?
mTORC1
AMPK
JNK
PKA
A primary downstream transcriptional coactivator associated with endurance training-induced mitochondrial biogenesis is:
PGC-1α
NFAT
p53 (tumor suppressor) only
HIF-2α
Mechanical tension from resistance exercise most directly activates protein synthesis through:
AMPK inhibition of mTORC1
mTORC1 activation via mechanosensitive pathways (e.g., phosphatidic acid)
Inhibition of insulin receptor substrate
Activation of glycogen phosphorylase
The acute rise in epinephrine during exercise primarily promotes:
Increased insulin secretion from pancreatic beta cells
Increased muscle glucose uptake independent of GLUT4
Hepatic glycogenolysis and adipose lipolysis
Suppression of heart rate
