2. Carbohydrates

Carbon, hydrogen, and oxygen

What elements compose carbohydrates?

4 kcal/g

How much energy do carbohydrates provide per gram?

Immediate energy source

What is the primary role of carbohydrates in the body?

They prevent protein from being used as an energy source

Why are carbohydrates called protein-sparers?

Brain cells and nervous system

Which organs primarily depend on glucose for energy?

Glycogen

In what form are carbohydrates stored in the body?

They regulate fat metabolism

What is the role of carbohydrates in fat metabolism?

By maintaining health and function in the GIT

How do carbohydrates support gastrointestinal health?

Simple (1–2 molecules) and complex (3 or more molecules)

How are carbohydrates classified based on structure?

Simple sugar units with the general formula C₆H₁₂O₆

What are monosaccharides?

Arrangement of atoms

What determines the sweetness of monosaccharides?

Glucose, fructose, galactose

What are the three major monosaccharides?

Blood sugar

What is glucose also known as?

It is the body’s major fuel and forms other carbohydrates

Why is glucose considered the most important monosaccharide?

Fructose

What is the sweetest natural sugar?

Fruits, sodas, cereals, desserts, HFCS

Where is fructose commonly found?

Galactose

Which monosaccharide is the least sweet?

Glucose (to form lactose)

Galactose is commonly combined with which sugar?

Pairs of monosaccharides linked together

What are disaccharides?

Glucose + glucose

Maltose is composed of which sugars?

Glucose + fructose

Sucrose is composed of which sugars?

Glucose + galactose

Lactose is composed of which sugars?

Condensation

What process forms disaccharides?

Hydrolysis

What process breaks down disaccharides during digestion?

Carbohydrates with 3–10 monosaccharides

What are oligosaccharides?

Raffinose and stachyose

Name two common oligosaccharides.

Carbohydrates made of 10 or more monosaccharides

What are polysaccharides?

Storage form of carbohydrates in the body

What is glycogen?

Chains of glucose found in plants

What is starch?

Intermediate product of starch hydrolysis

What is dextrin?

It cannot be broken down by human enzymes

Why is fiber not digested?

Soluble and insoluble

What are the two types of fiber?

Fermentation and cholesterol reduction

What is the main function of soluble fiber?

Increase stool bulk and prevent constipation

What is the main function of insoluble fiber?

Short-chain fatty acids (SCFA)

What do fibers produce when fermented?

Salivary amylase

What enzyme begins carbohydrate digestion in the mouth?

Dextrin and maltose

What products are formed by salivary amylase?

Small intestine

Where does most carbohydrate absorption occur?

Active transport

How are glucose and galactose absorbed?

Diffusion

How is fructose absorbed?

Before transport to the liver

Why are fructose and galactose converted to glucose?

Insulin

Which hormone facilitates glucose entry into cells?

Speed and magnitude of blood glucose rise

What does glycemic index measure?

It considers both quality and quantity of carbohydrates

What makes glycemic load more accurate than GI?

10% of total energy

Maximum recommended sugar intake?

45–65% of total energy

Recommended carbohydrate (starch) intake?

20–25 grams

Recommended fiber intake per day?

Which carbohydrate function explains its role in preventing ketosis?

Which monosaccharide is least sweet and rarely occurs freely in food?

Which process involves removal of water to form a disaccharide?

Which fiber type lowers cholesterol by fermentation in the colon?