Carbohydrate Metabolic Pathways

Vocabulary practice flashcards covering major carbohydrate metabolic pathways—including glycolysis, the citric acid cycle, oxidative phosphorylation, gluconeogenesis, glycogenesis, and glycogenolysis—along with clinical aspects of diabetes mellitus.

Carbohydrate Metabolism

The various biochemical processes responsible for the formation, breakdown, and interconversion of carbohydrates in living organisms.

Glucose

A simple sugar (monosaccharide) metabolized by nearly all known organisms, serving as the most important carbohydrate in living systems.

Glycolysis

An anaerobic, catabolic pathway occurring in the cytoplasm of plant and animal cells that converts one molecule of glucose ($6$ carbons) into two molecules of pyruvate ($3$ carbons), releasing energy as ATP and NADH while producing water across ten reactions.

Fates of Pyruvate

Metabolic routes determined by oxygen availability: converted to acetyl-CoA under aerobic conditions, reduced to lactate in vertebrates under anaerobic conditions, or converted to ethanol and $CO_2$ in microorganisms like yeast under anaerobic conditions.

Krebs Cycle (TCA Cycle)

The common pathway (also known as the citric acid cycle or tricarboxylic acid cycle) for the complete oxidation of carbohydrates, proteins, and lipids to acetyl-CoA or other intermediates, releasing two molecules of $CO_2$, recycling oxaloacetate, and generating ATP, NADH, and $FADH_2$.

Oxaloacetate

A $4$-carbon compound that combines with acetyl-CoA in the Krebs cycle to form $6$-carbon citrate and is regenerated as the cycle completes.

Oxidative Phosphorylation

The final step in cellular respiration that utilizes nutrients, oxygen, and an electron transport chain to generate ATP and water in both plant and animal cells.

Gluconeogenesis

An anabolic, endergonic process that produces glucose from non-carbohydrate carbon precursors (such as lactate, amino acids like alanine, and glycerol), occurring in both the mitochondria and cytoplasm, primarily in the liver.

Endogenous Glucose Pathway

An alternative name for gluconeogenesis, highlighting that it requires energy to synthesize glucose when dietary intake is lacking or insufficient.

Glycogenesis

A multi-step biological process (also known as glycogen synthesis) of forming glycogen from glucose to store for later use when glucose is not readily available.

Glucokinase

The liver isoform of hexokinase that initiates glycogenesis by catalyzing the conversion of glucose into glucose-6-phosphate.

Glycogenolysis

The biochemical pathway occurring in the liver and muscles in which glycogen breaks down into glucose-1-phosphate and glucose.

Diabetes Mellitus

A chronic disease that occurs either when the pancreas does not produce enough insulin or when the body cannot effectively use the insulin it produces.

Insulin

A hormone produced by the pancreas that regulates blood glucose levels.

Hyperglycaemia

Raised blood glucose or blood sugar levels, which is a common effect of uncontrolled diabetes that over time leads to serious damage to bodily systems, especially nerves and blood vessels.

Type 1 Diabetes

A chronic condition (previously known as insulin-dependent diabetes) characterized by deficient insulin production, requiring daily administration of insulin.

Type 2 Diabetes

An often preventable chronic condition affecting how the body uses sugar by preventing it from using insulin properly, associated with factors such as genetics, being overweight, and physical inactivity.

Gestational Diabetes

A form of hyperglycaemia occurring during pregnancy with blood glucose values above normal but below the diagnostic threshold for diabetes, typically diagnosed through prenatal screening.