Carbohydrates: Composition and Sources

Carbohydrate Composition

• Carbohydrates are composed of carbon, hydrogen, and oxygen.
• The basic formula for carbohydrates is CH₂O, meaning the ratio of these elements is 1:2:1.
• The term "hydrate" (water) refers to the combination of hydrogen and oxygen atoms in carbohydrates.

Carbohydrate Source

• Plants produce carbohydrates through photosynthesis.
• Plants use carbon dioxide (CO₂), water (H₂O), and energy from sunlight to create glucose and oxygen.
• The formula for photosynthesis is: 6CO₂ + 6H₂O + energy → C₆H₁₂O₆ + 6O₂

Carbohydrate Foods

• Common food sources of carbohydrates include fruits, breads, biscuits, rice, pasta, root vegetables, breakfast cereals, and potatoes.

Carbohydrate Nomenclature

• Carbohydrates are classified as either polyhydroxy aldehydes or ketones, or their derivatives.
• Glucose is an aldohexose, and fructose is a ketohexose. (Specific chemical structure examples are shown).

Carbohydrate Consumption and Related Issues

• Sources of sugars include soda, punch, cookies, candy, chocolate, desserts, sugary cereals, and ice cream.
• Sixty percent of a person's food should come from carbohydrates.
• Carbohydrates are the primary energy source for the body.
• Excess carbohydrates are stored as glycogen in the liver and muscles, or as fat tissue.

Carbohydrate-Related Diseases

• Diseases related to carbohydrates include diabetic ketoacidosis, hyperosmolar coma, and hypoglycemia, which can affect the central nervous system.

Carbohydrate Classification

• Carbohydrates are classified into four main groups:
  • Monosaccharides
  • Disaccharides
  • Oligosaccharides
  • Polysaccharides

Types of Carbohydrates

• Simple carbohydrates include monosaccharides and disaccharides.
• Complex carbohydrates include oligosaccharides and polysaccharides.

Simple Carbohydrates

• Simple carbohydrates are quick energy sources.
• They are commonly found in sugars.
• Simple carbohydrates usually do not provide vitamins, minerals, or dietary fiber.

Complex Carbohydrates

• Complex carbohydrates provide vitamins, minerals, and dietary fiber.
• Complex carbohydrates provide longer-lasting energy.
• Foods such as breads, rice, pasta, legumes, and starchy vegetables contain complex carbohydrates.

Carbohydrate Functions

• Energy: Glucose is the primary fuel source for most body cells, particularly nerve tissue and red blood cells. Excess glucose is stored as glycogen.
• Sparing Body Protein: If carbohydrate intake is insufficient, the body will use protein to synthesize glucose.
• Preventing Ketosis: Carbohydrates are needed to break down fats completely, with insufficient carbohydrate intake, incomplete fat metabolism may produce ketones, resulting in ketosis.
• Fiber: Carbohydrate fiber contributes to satiety, helps lower blood cholesterol, helps lower risk of Type II diabetes, and promotes intestinal health.

Biological Roles of Carbohydrates

• Carbohydrates serve as nutrients and energy storage.
• They also contribute to structural and protective roles, such as bone lubricants, cellular adhesion, and intracellular signaling/cell recognition.

References

• Lippincott's Biochemistry
• Harper's Biochemistry

Explore the fascinating world of carbohydrates, including their composition, sources, and food examples. Understand how plants produce carbohydrates and the importance of their chemical structure. This quiz will test your knowledge of carbohydrate nomenclature and consumption issues.