Question 1

A heparinized blood sample is received in the chemistry laboratory.After centrifugation,the plasma appears markedly hemolyzed.If the hexokinase method is used in this lab to measure glucose,why should this specimen be re-collected?

A) Heparin interferes with the second enzyme in the hexokinase assay.
B) Hemoglobin competes with the chromogen for hydrogen peroxide and inhibits the hexokinase reaction.
C) Red blood cells contain phosphate esters and enzymes that interfere with the hexokinase assay.
D) There is no need for re-collection as neither hemolysis nor heparin interfere with the hexokinase assay.

Accepted Answer

Hemolysis releases intracellular components from red blood cells, including enzymes and phosphate esters, which can interfere with the hexokinase assay for glucose measurement.

Question 2

What effect does salicylate have on blood glucose value?&#10;A) Increases&#10;B) Decreases

Accepted Answer

Salicylates have been shown to decrease blood glucose values by enhancing insulin sensitivity and improving glucose uptake in peripheral tissues.

Question 3

The breakdown of glycogen stores in the liver to increase serum glucose is referred to as:&#10;A) glycogenolysis.&#10;B) glycolysis.&#10;C) gluconeogenesis.&#10;D) glycogenesis.

Accepted Answer

Glycogenolysis is the process by which glycogen stores in the liver are broken down to increase serum glucose levels. Glycolysis is the breakdown of glucose for energy production. Gluconeogenesis is the synthesis of new glucose molecules from non-carbohydrate sources such as amino acids or fatty acids. Glycogenesis is the synthesis of glycogen from glucose molecules for storage.

Question 4

What effect does epinephrine have on blood glucose value?&#10;A) Increases&#10;B) Decreases

Accepted Answer

Epinephrine increases blood glucose value by stimulating liver glycogenolysis and inhibiting insulin secretion from the pancreas. This helps release glucose into the bloodstream to prepare the body for fight or flight response.

Question 5

The glucose assay on an analyzer uses hexokinase as the enzyme that phosphorylates glucose.What are the initial products formed from the first step of this reaction?&#10;A) Nicotinamide adenine dinucleotide and NADH&#10;B) 6-Phosphogluconate and hydrogen ions&#10;C) Glycosylated hemoglobin&#10;D) Glucose-6-phosphate and adenosine diphosphate (ADP)

Accepted Answer

The enzyme hexokinase catalyzes the phosphorylation of glucose. In this reaction, glucose reacts with ATP to form ADP and glucose-6-phosphate (G6P), which is the initial product formed in the first step of the reaction. Therefore, answer D is correct. Answer A is incorrect because nicotinamide adenine dinucleotide (NAD) and NADH are not involved in this reaction. Answer B is incorrect because 6-phosphogluconate is not a product of the glucose assay reaction. Answer C is also incorrect because glycosylated hemoglobin is not involved in the glucose assay reaction.

Question 6

A type 1 diabetic who is in the early stages of the disease is taken to the emergency room with symptoms of hypoglycemia.Which one of the following endogenous hormones might be the cause of this?&#10;A) Epinephrine&#10;B) Glucagon&#10;C) Cortisol&#10;D) Lactate

Accepted Answer

Glucagon is a hormone that raises blood glucose levels by promoting glycogen breakdown and gluconeogenesis. In type 1 diabetes, there can be dysregulation of glucagon secretion, leading to inappropriate release and potential hypoglycemia.

Question 7

The major storage carbohydrate in animals is _____,which is located most abundantly in _____.&#10;A) cellulose; vegetable fibers&#10;B) glycoprotein; cell membranes&#10;C) glycogen; the liver&#10;D) starch; skeletal muscle

Accepted Answer

The major storage carbohydrate in animals is glycogen. It is located most abundantly in the liver. Choice A is incorrect because cellulose is a storage carbohydrate in plants, not animals, and is not located in vegetable fibers. Choice B is incorrect because glycoprotein is a type of protein, not a storage carbohydrate. Choice D is incorrect because starch is a storage carbohydrate in plants, not animals, and is not located in skeletal muscle.

Question 8

Conversion of glucose into lactate or pyruvate is referred to as:&#10;A) glycogenesis.&#10;B) glycogenolysis.&#10;C) glyconeogenesis.&#10;D) glycolysis.

Accepted Answer

Conversion of glucose into lactate or pyruvate is a key step in the metabolic pathway called glycolysis. Glycogenesis is the formation of glycogen from glucose, glycogenolysis is the breakdown of glycogen to release glucose, and gluconeogenesis is the synthesis of glucose from non-carbohydrate sources.

Question 9

Blood is collected in a tube containing no anticoagulant and is transported uncentrifuged to the laboratory from an outpatient clinic.Transport time at room temperature,accessioning,and sample preparation time equal approximately hours.If a serum glucose level is requested for this tube of blood,how might the results be affected by the timing?

A) The glucose value would be decreased by 50%.
B) The glucose value would be increased by approximately 15%.
C) The glucose value would be decreased by approximately 5%.
D) There would be no effect on the glucose value.

Accepted Answer

Glucose is metabolized by red blood cells at a rate of approximately 15% per hour at room temperature. Therefore, the glucose value would be decreased by approximately 15% if the transport and preparation time is 1 hour.

Question 10

A 75-year-old man was brought by his daughter to a hospital emergency department.He was in a confused state,trembling,sweating,with a rapid pulse,lightheadedness,and complaining of hunger and epigastric discomfort.His daughter claims that he does not drink alcohol and that he takes oral hypoglycemic drugs to control his diabetes.What is the likely cause of his symptoms?

A) The oral hypoglycemic drugs are affecting his thyroid gland.
B) He is likely suffering from pheochromocytoma and the effects of increased epinephrine.
C) He has possibly taken too much of his medication and is suffering from hypoglycemia.
D) His diabetes is not being adequately controlled and is leading to lactic alkalosis.

Accepted Answer

The symptoms are consistent with those of hypoglycemia, and the fact that the patient takes oral hypoglycemic drugs and is complaining of hunger and epigastric discomfort supports this diagnosis. The other answer choices are less likely based on the given information.

Question 11

In an individual with a normal hematocrit,whole-blood glucose values are approximately what percent different from plasma glucose values?&#10;A) 20% higher&#10;B) 10% lower&#10;C) 50% higher&#10;D) There is no difference between whole blood glucose and plasma glucose values.

Accepted Answer

The answer of In an individual with a normal hematocrit,whole-blood...

Question 12

An example of a monosaccharide would be:&#10;A) glucose.&#10;B) maltose.&#10;C) sucrose.&#10;D) starch.

Accepted Answer

The answer of An example of a monosaccharide would be:&#10;A)...

Question 13

What is the classic test to determine a diagnosis of hypoglycemia?&#10;A) Assessment of fasting blood glucose during a hypoglycemic episode&#10;B) A 72-hour fast&#10;C) Postprandial glucose analysis&#10;D) Oral glucose tolerance test

Accepted Answer

The answer of What is the classic test to determine...

Question 14

Which one of the following has as one of its biological functions the regulation of the lifespan of proteins?&#10;A) Glycoproteins&#10;B) Glucose&#10;C) Lactate&#10;D) Ketones

Accepted Answer

The answer of Which one of the following has as...

Question 15

What effect does septicemia have on blood glucose value?&#10;A) Increases&#10;B) Decreases

Accepted Answer

The answer of What effect does septicemia have on blood...

Question 16

By what mechanism does glucagon promote hyperglycemia?&#10;A) Glucagon promotes glycogenesis.&#10;B) Glucagon stimulates insulin release.&#10;C) Glucagon stimulates glucose synthesis by gluconeogenesis.&#10;D) Glucagon promotes hypoglycemia,not hyperglycemia.

Accepted Answer

The answer of By what mechanism does glucagon promote hyperglycemia?&#10;A)...

Question 17

What effect does glucagon have on blood glucose value?&#10;A) Increases&#10;B) Decreases

Accepted Answer

The answer of What effect does glucagon have on blood...

Question 18

Which one of the following coupled-enzyme glucose methods requires extended incubation time to allow for the spontaneous conversion of the $\alpha$ -form of glucose to the $\beta$ -form so that both forms can react with the initial enzyme in the reaction?

A) Hexokinase method
B) Glucose oxidase method
C) Self-monitoring method
D) Polarographic method

Accepted Answer

The answer of Which one of the following coupled-enzyme glucose...

Question 19

What effect does ethanol have on blood glucose value?&#10;A) Increases&#10;B) Decreases

Accepted Answer

The answer of What effect does ethanol have on blood...

Deck 22: Carbohydrates