Glycolysis Practice Questions

Question 1

A 4-month-old boy is brought to his pediatrician for a well-child visit. His parents have noticed that he has had poor growth compared to his older siblings. The boy was delivered vaginally after a normal pregnancy. His temperature is 98.8°F (37.1°C), blood pressure is 98/68 mmHg, pulse is 88/min, and respirations are 20/min. On exam, his abdomen appears protuberant, and the boy appears to have abnormally enlarged cheeks. A finger stick reveals that the patient’s fasting blood glucose is 50 mg/dL. On further laboratory testing, the patient is found to have elevated blood lactate levels, as well as no response to a glucagon stimulation test. What enzymatic defect is most likely present?

Accepted Answer

Glucose-6-phosphatase

Answer

Alpha-1,4-glucosidase

Answer

Glycogen synthase

Answer

Alpha-1,6-glucosidase

Answer

Glycogen phosphorylase

Question 2

Certain glucose transporters that are expressed predominantly on skeletal muscle cells and adipocytes are unique compared to those transporters found on other cell types within the body. Without directly affecting glucose transport in other cell types, which of the following would be most likely to selectively increase glucose uptake in skeletal muscle cells and adipocytes?

Accepted Answer

Increased levels of circulating insulin

Answer

Increased plasma glucose concentration

Answer

It is physiologically impossible to selectively increase glucose uptake in specific cells

Answer

Decreased plasma glucose concentration

Answer

Decreased levels of circulating insulin

Question 3

A 14-year-old female with no past medical history presents to the emergency department with nausea and abdominal pain. On physical examination, her blood pressure is 78/65, her respiratory rate is 30, her breath has a fruity odor, and capillary refill is > 3 seconds. Serum glucose is 820 mg/dL. After starting IV fluids, what is the next best step in the management of this patient?

Accepted Answer

Intravenous regular insulin

Answer

Intravenous Dextrose in water

Answer

Subcutaneous insulin glargine

Answer

Intravenous glucagon

Answer

Subcutaneous insulin lispro

Question 4

An 11-year-old boy is brought to the emergency room with acute abdominal pain and hematuria. Past medical history is significant for malaria. On physical examination, he has jaundice and a generalized pallor. His hemoglobin is 5 g/dL, and his peripheral blood smear reveals fragmented RBC, microspherocytes, and eccentrocytes (bite cells). Which of the following reactions catalyzed by the enzyme is most likely deficient in this patient?

Accepted Answer

D-glucose-6-phosphate + NADP+ → 6-phospho-D-glucono-1,5-lactone + NADPH + H+

Answer

Glucose-1-phosphate + UTP → UDP-glucose + pyrophosphate

Answer

Glucose + ATP → Glucose-6-phosphate + ADP + H+

Answer

D-glucose 6-phosphate → D-fructose-6-phosphate

Answer

Glucose-6-phosphate + H2O → glucose + Pi

Question 5

An 8-year old boy is brought to the emergency department because he has been lethargic and has had several episodes of nausea and vomiting for the past day. He has also had increased thirst over the past two months. He has lost 5.4 kg (11.9 lbs) during this time. He is otherwise healthy and has no history of serious illness. His temperature is 37.5 °C (99.5 °F), blood pressure is 95/68 mm Hg, pulse is 110/min, and respirations are 30/min. He is somnolent and slightly confused. His mucous membranes are dry. Laboratory studies show:
Hemoglobin 16.2 g/dL
Leukocyte count 9,500/mm3
Platelet count 380,000/mm3
Serum
Na+ 130 mEq/L
K+ 5.5 mEq/L
Cl- 99 mEq/L
HCO3- 16 mEq/L
Creatinine 1.2 mg/dL
Glucose 570 mg/dL
Ketones positive
Blood gases, arterial
pH 7.25
pCO2 21 mm Hg
Which of the following is the most appropriate next step in management?

Accepted Answer

Intravenous hydration with 0.9% normal saline and insulin

Answer

Intravenous hydration with 0.45% normal saline and insulin

Answer

Intravenous hydration with 5% dextrose solution and 0.45% normal saline

Answer

Intravenous sodium bicarbonate

Answer

Intravenous hydration with 0.9% normal saline and potassium chloride

Question 6

The balance between glycolysis and gluconeogenesis is regulated at several steps, and accumulation of one or more products/chemicals can either promote or inhibit one or more enzymes in either pathway. Which of the following molecules if increased in concentration can promote gluconeogenesis?

Accepted Answer

Acetyl-CoA

Answer

ADP

Answer

AMP

Answer

Fructose-2,6-bisphosphate

Answer

Insulin

Question 7

A 22-year-old man presents to his primary care provider because of fever, diarrhea, and abdominal cramps. He has returned from Dhaka, Bangladesh recently where he was visiting his relatives. He is diagnosed with Shigella infection, and ciprofloxacin is started. He develops severe nausea and weakness 2 days later and complains of passing dark urine. The lab test results reveal a hemoglobin level of 7.9 g/dL, increased unconjugated bilirubin, increased reticulocyte count, increased lactate dehydrogenase, and increased blood urea. Which of the following is the best next step for the diagnosis of this patient’s condition?

Accepted Answer

Glucose-6-phosphate dehydrogenase (G6PD) enzyme assay

Answer

Direct antiglobulin (Coombs) test

Answer

ADAMTS-13 activity assay

Answer

Eosin-5-maleimide (EMA) binding test

Answer

Hemoglobin electrophoresis

Question 8

A 12-year-old boy and his siblings are referred to a geneticist for evaluation of a mild but chronic hemolytic anemia that has presented with fatigue, splenomegaly, and scleral icterus. Coombs test is negative and blood smear does not show any abnormal findings. An enzymatic panel is assayed, and pyruvate kinase is found to be mutated on both alleles. The geneticist explains that pyruvate kinase functions in glycolysis and is involved in a classic example of feed-forward regulation. Which of the following metabolites is able to activate pyruvate kinase?

Accepted Answer

Fructose-1,6-bisphosphate

Answer

Alanine

Answer

ATP

Answer

Glucose-6-phosphate

Answer

Glyceraldehyde-3-phosphate

Question 9

A 1-year-old male with a history of recurrent pseudomonal respiratory infections and steatorrhea presents to the pediatrician for a sweat test. The results demonstrate a chloride concentration of 70 mEq/L (nl < 40 mEq/L). Which of the following defects has a similar AUTOSOMAL RECESSIVE mode of inheritance as the disorder experienced by this patient?

Accepted Answer

Accumulation of glycogen in the lysosome

Answer

Abnormal production of type IV collagen

Answer

Trinucleotide repeat expansion of CAG on chromosome 4

Answer

Mutated gene for mitochondrial-tRNA-Lys

Answer

Inability to convert carbamoyl phosphate and ornithine into citrulline

Question 10

An 11-month-old boy is brought to a pediatrician by his parents with a recurrent cough, which he has had since the age of 2 months. He has required 3 hospitalizations for severe wheezing episodes. His mother also mentions that he often has diarrhea. The boy’s detailed history reveals that he required hospitalization for meconium ileus during the neonatal period. Upon physical examination, his temperature is 37.0°C (98.6ºF), pulse rate is 104/min, respiratory rate is 40/min, and blood pressure is 55/33 mm Hg. An examination of the boy’s respiratory system reveals the presence of bilateral wheezing and scattered crepitations. An examination of his cardiovascular system does not reveal any abnormality. His length is 67.3 cm (26.5 in) and weight is 15 kg (33 lbs). His sweat chloride level is 74 mmol/L. His genetic evaluation confirms that he has an autosomal recessive disorder resulting in a dysfunctional membrane-bound protein.  Which of the following best describes the mechanism associated with the most common mutation that causes this disorder?

Accepted Answer

Defective maturation and early degradation of the protein

Answer

Decreased chloride transport through the protein

Answer

Disordered regulation of the protein

Answer

Decreased transcription of the protein due to splicing defect

Answer

Complete absence of the protein

Glycolysis

Study Resources

Lessons

Questions

Flashcards

Lessons

Overview and regulation of glycolysis

Preparatory phase reactions

Pay-off phase reactions

Rate-limiting enzymes and control points

Energy yield and ATP production

Fates of pyruvate

Substrate-level phosphorylation

Feeder pathways to glycolysis

Glycolysis in different tissues

Disorders of glycolytic enzymes

Alternative glycolytic pathways

Practice Questions

Flashcards

About Glycolysis for USMLE

Lessons in Glycolysis

Master Glycolysis