Carbohydrates & Metabolism Flashcards
The two forms of carbohydrates are ___ and ___.
aldose; ketose.
Determine the following structure.
Ketose (ketone).
Determine the following structure.
Aldose (aldehyde).
Define stereoisomers.
The same order and types of bonds but different spatial arrangements and different properties.
Define enantiomers.
Images that cannot be overlapped and are nonsuperimposable.
Determine the following structure.
D-Glucose.
Determine the following structure.
L-Glucose.
What are the common monosaccharides?
Glucose, fructose, and galactose.
What are the common disaccharides?
Lactose and sucrose.
What are the common polysaccharides?
Starch (glucose molecules) and glycogen.
What does it mean for a carbohydrate to be described as a reducing substance?
Carbohydrates that can reduce other compounds.
To be considered a reducing substance, the carbohydrate must contain a ___ or an ___ group.
ketone; aldehyde.
(T/F) Carbohydrates can form glycosidic bonds with only other carbohydrates.
False, they can form glycosidic bonds with carbohydrates and noncarbohydrates.
Nonreducing carbohydrates are lacking what structure?
Active ketone or aldehyde group.
What is the most common nonreducing sugar?
Sucrose - table sugar.
The nervous system, including the brain, totally depends on which energy source for energy?
Glucose.
What occurs when the concentration of glucose falls below a certain level within extracellular fluid?
The nervous tissue loses the primary energy source and is incapable of maintaining normal function.
Which enzyme is responsible for the digestion of nonabsorbable polymers to dextrins and disaccharides?
Salivary and pancreatic amylase.
Glucose is the only carbohydrate to be directly used for energy or stored as what?
Glycogen.
The ultimate goal of the cell is to convert glucose to what?
Carbon dioxide and water.
The first step for all pathways of energy synthesis requires glucose to be converted to what?
Glucose-6-phosphate.
Glucose-6-phosphate can enter which two pathways to be converted to energy from glucose?
Embden-Meyerhof Pathway or the hexose monophosphate pathway (HMP).
Describe the Embden-Meyerhof pathway.
Glucose is broken down into two- and three-carbon molecules of pyruvic acid that can enter the TCA cycle on conversion to acetyl-CoA.
Describe gluconeogenesis.
The conversion of amino acids by the liver and kidneys to substrates that can be converted to glucose. Encompasses the conversion of glycerol, lactate, and pyruvate to glucose.
In glycolysis, tissues can derive ___ from ___ in an oxygen-deficient environment by converting pyruvic acid into ___ acid.
ATP; glucose; lactic.
For anaerobic glycolysis to occur, how many moles of ATP must be consumed for each mole of glucose?
2 moles.
Describe the energy pathway HMP shunt.
A detour of glucose-6-phosphate from the glycolytic pathway to become 6-phosphogluconic acid.
___ is important to erythrocytes that lack mitochondria and are therefore incapable of the TCA cycle.
NADPH.