Classification and Functions of Carbohydrates

Study Notes

Classification of Carbohydrates

Carbohydrates are organic compounds composed of carbon, hydrogen, and oxygen, typically with a 1:2:1 ratio (e.g., C₆H₁₂O₆).
They are broadly classified into monosaccharides, disaccharides, and polysaccharides.
Monosaccharides are the simplest form, including glucose, fructose, and galactose.
Disaccharides are formed by the linkage of two monosaccharides (e.g., sucrose = glucose + fructose; lactose = glucose + galactose).
Polysaccharides are complex carbohydrates formed by the linkage of many monosaccharides (e.g., starch, glycogen, cellulose).

Functions of Carbohydrates

Provide energy: Carbohydrates are the primary source of energy for the body. Glucose, a monosaccharide, is the body's preferred energy source.
Structural support: Cellulose is a structural component of plant cell walls.
Storage of energy: Glycogen is the storage form of glucose in animals. Starch is the storage form of glucose in plants.
Dietary fiber: Some carbohydrates are indigestible and act as dietary fiber, promoting gut health.

Monosaccharides

These are the simplest carbohydrates.
Important examples include glucose, fructose, and galactose.
Glucose is crucial for cellular respiration and energy production.
Fructose is found in fruits and honey, and is metabolized differently than glucose.
Galactose is a component of lactose (milk sugar).

Disaccharides

Formed by the condensation reaction of two monosaccharides, releasing a water molecule.
Examples include sucrose (glucose + fructose), lactose (glucose + galactose), and maltose (glucose + glucose).
Sucrose is table sugar; lactose is found in milk; maltose is a product of starch digestion.

Polysaccharides

Complex carbohydrates composed of many monosaccharides linked together.
Starch is a storage polysaccharide in plants.
Glycogen is a storage polysaccharide in animals.
Cellulose is a structural polysaccharide in plant cell walls.

Digestion and Absorption

Carbohydrate digestion begins in the mouth with salivary amylase.
Pancreatic amylase further breaks down carbohydrates in the small intestine.
Monosaccharides are absorbed into the bloodstream and transported to cells for energy production.
The body regulates blood glucose levels using hormones like insulin and glucagon.

Sources of Carbohydrates

Dietary sources include grains, fruits, vegetables, and dairy products.
Refined carbohydrates, often processed, may have lower nutritional value.
Unrefined carbohydrates, often whole foods, contain more fibre.

Health Implications

Excess carbohydrate intake can lead to weight gain and potential health issues, including type 2 diabetes.
A balanced diet including complex carbohydrates is recommended.
Adequate intake of dietary fiber is vital for digestive health.

Types of Dietary Fibers

Soluble fiber: Dissolves in water, can help lower cholesterol and regulate blood sugar.
Insoluble fiber: Doesn't dissolve in water, aids in bowel regularity.
Both types are crucial for good digestive health.

Description

This quiz covers the classification of carbohydrates, including monosaccharides, disaccharides, and polysaccharides. It also explores the essential functions carbohydrates serve in providing energy, structural support, and energy storage. Test your knowledge on these vital organic compounds.