Deck 22: Carbohydrates

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.

Answer 1

Red blood cells contain phosphate esters and enzymes that interfere with the hexokinase assay.

Question 2

What effect does salicylate have on blood glucose value?

A) Increases
B) Decreases

Answer 2

Decreases

Question 3

The breakdown of glycogen stores in the liver to increase serum glucose is referred to as:

A) glycogenolysis.
B) glycolysis.
C) gluconeogenesis.
D) glycogenesis.

Answer 3

glycogenolysis.

Question 4

What effect does epinephrine have on blood glucose value?

A) Increases
B) Decreases

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?

A) Nicotinamide adenine dinucleotide and NADH
B) 6-Phosphogluconate and hydrogen ions
C) Glycosylated hemoglobin
D) Glucose-6-phosphate and adenosine diphosphate (ADP)

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?

A) Epinephrine
B) Glucagon
C) Cortisol
D) Lactate

Question 7

The major storage carbohydrate in animals is _____,which is located most abundantly in _____.

A) cellulose; vegetable fibers
B) glycoprotein; cell membranes
C) glycogen; the liver
D) starch; skeletal muscle

Question 8

Conversion of glucose into lactate or pyruvate is referred to as:

A) glycogenesis.
B) glycogenolysis.
C) glyconeogenesis.
D) glycolysis.

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.

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.

Question 11

In an individual with a normal hematocrit,whole-blood glucose values are approximately what percent different from plasma glucose values?

A) 20% higher
B) 10% lower
C) 50% higher
D) There is no difference between whole blood glucose and plasma glucose values.

Question 12

An example of a monosaccharide would be:

A) glucose.
B) maltose.
C) sucrose.
D) starch.

Question 13

What is the classic test to determine a diagnosis of hypoglycemia?

A) Assessment of fasting blood glucose during a hypoglycemic episode
B) A 72-hour fast
C) Postprandial glucose analysis
D) Oral glucose tolerance test

Question 14

Which one of the following has as one of its biological functions the regulation of the lifespan of proteins?

A) Glycoproteins
B) Glucose
C) Lactate
D) Ketones

Question 15

What effect does septicemia have on blood glucose value?

A) Increases
B) Decreases

Question 16

By what mechanism does glucagon promote hyperglycemia?

A) Glucagon promotes glycogenesis.
B) Glucagon stimulates insulin release.
C) Glucagon stimulates glucose synthesis by gluconeogenesis.
D) Glucagon promotes hypoglycemia,not hyperglycemia.

Question 17

What effect does glucagon have on blood glucose value?

A) Increases
B) Decreases

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

Question 19

What effect does ethanol have on blood glucose value?

A) Increases
B) Decreases