Carbohydrates and Metabolism Lecture Notes

A comprehensive set of vocabulary flashcards covering carbohydrate classification, digestion, metabolism, health recommendations, and related clinical conditions based on lecture notes.

Simple carbohydrates

Small compounds consisting of either one or two sugar molecules, known as monosaccharides or disaccharides.

Complex carbohydrates

Larger compounds containing more than three sugar molecules linked together.

Monosaccharides

The simplest unit of carbohydrate (mono = 1, saccharide = sugar), consisting of carbon, hydrogen, and oxygen.

Glucose

A monosaccharide that serves as the primary form of fuel for brain function.

Fructose

A monosaccharide found in fruit, often referred to as "fruit sugar."

Galactose

A monosaccharide not commonly found alone in food; it typically binds to lactose to form a disaccharide.

Sucrose

A disaccharide consisting of one glucose molecule and one fructose molecule.

Lactose

A disaccharide consisting of one glucose molecule and one galactose molecule.

Maltose

A disaccharide consisting of two glucose molecules; it is a byproduct of the breakdown of larger compounds like starch.

Oligosaccharides

Complex carbohydrates containing 3 to 10 monosaccharides, found in beans, legumes, whole grains, and some sports drinks.

Polysaccharides

Complex carbohydrates containing more than 10 monosaccharides, found in the human diet as starch, fiber, and glycogen.

High-quality carbohydrate

Minimally processed carbohydrates made from whole grains that contain original nutrients and fiber.

Low-quality carbohydrate

Extremely processed carbohydrates where components of whole grains are removed, resulting in less fiber, vitamins, and minerals.

Starch

A plant-based polysaccharide consisting of glucose molecules bound by alpha bonds which are breakable by human digestive enzymes.

Amylose

A common form of starch consisting of a straight chain of glucose molecules.

Amylopectin

A form of starch consisting of multi-branched chains of glucose molecules.

Fiber

A polysaccharide found in plants containing beta bonds that cannot be broken by human enzymes, making it non-digestible.

Soluble fiber

Fiber that dissolves in water to form a jelly-like consistency and is fermented by intestinal bacteria; found in citrus fruits, berries, oats, and beans.

Insoluble fiber

The structural component of plant cell walls that is not soluble in water and is usually non-fermentable; found in whole grains and vegetables.

Glycogen

The storage form of glucose in the body, which is highly branched and stored in skeletal muscles (about three-quarters) and the liver (about one-quarter).

Amylase

An enzyme that begins the chemical digestion of starch into simpler carbohydrates in the mouth and small intestine.

Insulin

A hormone released by the pancreas that stimulates glucose uptake from the blood into tissue cells to lower blood sugar.

Glucagon

A hormone released by the pancreas that stimulates the breakdown of liver glycogen into glucose to raise blood sugar.

Normal blood glucose range

$70-100\,mg/dL$ ($3.9\text{--}5.5\,mmol/L$).

Gluconeogenesis

The process by which the liver produces glucose, approximately $5\,g$ per hour or $120\,g$ per day.

Glycolysis

The metabolic pathway used to produce energy anaerobically, which is dependent on glucose.

Lactose intolerance

A condition where the small intestine does not produce enough lactase, preventing the digestion of the disaccharide lactose.

Celiac disease

An autoimmune disorder triggered by gluten that results in damage to the small intestinal mucosa and reduced nutrient absorption.

Gluten

A protein sequence located in the prolamin fraction of wheat, barley, and rye.

Sugar alcohols

Natural or lab-made carbohydrates like xylitol and sorbitol that contain $2\,kcal/g$ and do not promote tooth decay.

Cytokines

Inflammatory messengers associated with high intakes of highly refined carbohydrates and increased blood sugar levels.

Type 1 Diabetes mellitus

A condition where the pancreas is unable to produce insulin, preventing glucose from entering cells.

Type 2 Diabetes mellitus

A condition where cells become resistant to insulin, preventing the normal uptake of glucose into the cell membrane.

Oral Glucose Tolerance Test (OGTT)

A diagnostic test where a patient ingests $75\,g$ of glucose; levels of $200\,mg/dL$ or higher after three hours indicate diabetes mellitus.

Athlete carbohydrate recommendations

$3\text{ to }12\,g/kg$ of body weight per day, depending on exercise intensity and duration.