Nutritional Sciences: Carbohydrates

Flashcards covering the classification, structure, digestion, and hormonal regulation of carbohydrates, as well as the types and risks of diabetes.

Simple Carbohydrates

Organic compounds containing one or more sugar molecules, classified into monosaccharides and disaccharides.

Monosaccharides

The simplest form of carbohydrates consisting of a single sugar unit; common food forms include glucose, fructose, and galactose.

Disaccharides

Simple carbohydrates formed by two monosaccharides bonded together, such as lactose, sucrose, and maltose.

Hexose Sugars

Monosaccharides that contain $6$ carbon, $12$ hydrogen, and $6$ oxygen atoms, following a ratio of $1C:2H:1O$.

Glucose

The most abundant monosaccharide in the body and blood; it is the preferred energy source for the nervous system and red blood cells.

Photosynthesis

The process by which plants use light energy to convert $6$ molecules of carbon dioxide ($CO_2$) and $6$ molecules of water ($H_2O$) into $1$ molecule of glucose ($C_6H_{12}O_6$) and $6$ molecules of oxygen ($O_2$).

Fructose

A hexose sugar with a $5$-sided ring structure; it is the most abundant sugar in fruits and vegetables.

Galactose

A monosaccharide primarily found in dairy products as part of lactose; in the body, it can be converted to glucose or used to make cell membranes.

Lactose

A disaccharide also known as "milk sugar," consisting of glucose bonded to galactose.

Maltose

A disaccharide consisting of two glucose molecules; it is formed during the breakdown of starch.

Sucrose

A disaccharide consisting of glucose bonded to fructose, commonly referred to as "table sugar."

Glycosidic Bond

A bond that joins monosaccharides; alpha ($\alpha$) bonds face down (found in maltose), while beta ($\beta$) bonds face up (found in lactose).

Oligosaccharides

Complex carbohydrates containing $3$ to $10$ sugar units, such as raffinose and stachyose; they are often found in beans and soybeans.

Polysaccharides

Complex carbohydrates containing more than $10$ sugar units, including starch, glycogen, and dietary fiber.

Amylose

A type of starch consisting of a linear, unbranched chain of glucose molecules bonded by $\alpha$-1,4 glycosidic bonds.

Amylopectin

A highly branched starch arrangement containing $\alpha$-1,4 glycosidic bonds and $\alpha$-1,6 glycosidic bonds at branch points.

Glycogen

The branched storage form of glucose in animals, found in the liver and skeletal muscles; it can be quickly hydrolyzed for glucose release.

Dietary Fiber

Naturally occurring plant carbohydrates that cannot be digested by the human small intestine, typically containing $\beta$-1,4 glycosidic bonds.

Diverticulosis

A condition characterized by the formation of small, protruding pouches called diverticula along the wall of the large intestine.

Whole-Grain Anatomy

The structure of a wheat kernel consisting of the bran (fiber), the germ (vitamins and minerals), and the endosperm (starch).

Dextrins

Intermediate products of starch digestion formed when salivary $\alpha$-amylase breaks down $\alpha$-1,4 glycosidic bonds in the mouth.

Hepatic Portal System

The circulatory route that transports absorbed monosaccharides from the small intestine directly to the liver.

Glycemic Index (GI)

A scale from $0$ to $100$ that ranks foods based on the blood glucose response they trigger compared to a standard (usually $50g$ of pure glucose).

Glycemic Load (GL)

A measure of the glycemic response that accounts for portion size, calculated as $GL = (GI / 100) \times \text{grams of carbohydrate per serving}$.

Insulin

A hormone secreted by pancreatic beta ($\beta$) cells that stimulates glucose uptake into cells and lowers blood glucose levels.

Glucagon

A hormone secreted by pancreatic alpha ($\alpha$) cells that stimulates glycogenolysis and gluconeogenesis to increase blood glucose levels.

Glycogenesis

The hormonal process, promoted by insulin, of converting glucose into glycogen for energy storage.

Glycogenolysis

The breakdown of stored glycogen into glucose; stimulated by glucagon in the liver and epinephrine in skeletal muscle.

Gluconeogenesis

The synthesis of glucose from noncarbohydrate sources such as amino acids, glycerol, and lactate.

Ketogenesis

The process of fatty acid breakdown in the liver in the relative absence of glucose, leading to the production of ketones.

Type 1 Diabetes

An autoimmune disease where the immune system destroys pancreatic beta ($\beta$) cells, resulting in a lack of insulin production.

Type 2 Diabetes

The most common form of diabetes, characterized by insulin resistance where skeletal muscle and adipose tissue fail to respond properly to insulin.

Gestational Diabetes

A temporary form of diabetes occurring during pregnancy characterized by insulin resistance brought on by hormonal changes.

Secondary Diabetes

A form of diabetes brought on by other diseases, medical conditions, or specific medications.