Module 2: Carbohydrates Flashcards
Glucose (fasting) reference range
3.3 - 6.0 mmol/L
Glucose (random) reference range
3.3 - 11.0 mmol/L
The most common form of glucose in the body
Beta-D-glucose
Which cells have enzymes for gluconeogenesis?
Hepatic cells and renal tubular cells
Low blood glucose causes release of:
Glucagon from pancreatic alpha cells
High blood glucose causes release of:
Insulin from pancreatic beta cells
3 main classifications of carbohydrates
Monosaccharides, oligosaccharides (1-10 monosaccharides), polysaccharides (more than 10 monosaccharides)
3 main dietary monosaccharides
Glucose, fructose, galactose
Isomers
Molecules with the same molecular formula, but different arrangements
3 common disaccharides and the monosaccharides that make them
Sucrose = glucose + fructose Lactose = galactose + glucose Maltose = glucose + glucose
The enzyme that digests starch and its two sources in the body
Amylase - saliva and pancreatic juice
Which class of carbohydrates are absorbed?
Monosaccharides
Carbohydrates
Organic biomolecules composed mostly of carbon, hydrogen, and oxygen
They can be either aldehydes or ketones
Gluconeogenesis
Conversion of non-carbohydrates into glucose
Glucose oxidase converts glucose into gluconic acid and:
Hydrogen peroxide
Hexokinase catalyzes the formation of what?
Glucose-6-phosphate
In which glucose assay is the rate of oxygen disappearance measured?
Glucose oxidase
Which method is most specific for beta-D-glucose?
Glucose oxidase
Reference range for HbA1c
4.0-6.0% of total Hb
Ketone bodies
Acetone
Acetoacetic acid
Beta-hydroxybutyric acid
What is measured as a signal in an amperometric glucose oxidase method?
Consumption of O2
What is measured as a signal in a colormetric glucose oxidase method?
Oxidized chromogen
What is measured as a signal in a glucose hexokinase method?
NADPH
Which sample type has lower glucose levels: serum or whole blood. By how much, and why?
Whole blood has lower glucose levels by approx. 10% because of volume (glucose is measured by concentration)
Lab criteria for determining the presence of diabetes mellitus
2 of the following on different days: Fasting glucose >7.0mmol/L 2h PP glucose >11.1mmol/L Random glucose >11.1mmol/L with symptoms HbA1c >= 6.5%
What 2 monosaccharides make up sucrose?
Glucose and fructose
What 2 monosaccharides make up lactose?
Glucose and galactose
What 2 monosaccharides make up maltose?
2 glucose molecules
Glycogenesis
Conversion of glucose to glycogen in the cell (for storage)
Glycogenolysis
Conversion of glycogen to glucose in the cell (release of stored glucose)
Anaerobic glycolysis
Non-oxygen dependent catabolism of G-6-P (via the Embden-Meyerhof pathway) into 2 pyruvates; and in anaerobic conditions (mainly in muscle), conversion of pyruvate into lactate
Aerobic glycolysis
Further oxygen dependent oxidation of pyruvate in the mitochondria occurs to produce a lot of ATP and reduced coenzymes (eg. NADH)
The typical difference between serum and whole blood glucose values
Whole blood values are about 10% lower than serum
What would be the effect on the HbA1c result in a patient with a chronic hemolytic anemia?
Falsely decreased
