Question

An example of a monosaccharide is _______. a. fructose b. glucose c. galactose d. all of the above

Short answer

a. Fructose b. Glucose c. Galactose d. All of the above Answer: d. All of the above

Step-by-step solution

Identify monosaccharides

A monosaccharide is the simplest form of carbohydrate, consisting of a single sugar molecule. They serve as the building blocks for more complex carbohydrates.

Analyze option a (fructose)

Fructose is a simple sugar found in fruits, honey, and some vegetables. It has the molecular formula C6H12O6 and is a monosaccharide since it consists of a single sugar molecule.

Analyze option b (glucose)

Glucose is another simple sugar with the molecular formula C6H12O6. It is one of the primary energy sources for living organisms, and it serves as a monosaccharide because it consists of a single sugar molecule.

Analyze option c (galactose)

Galactose is a simple sugar with the molecular formula C6H12O6, commonly found in milk and dairy products. It is a monosaccharide since it consists of a single sugar molecule.

Combine the findings and choose the correct answer

Based on our analysis, fructose, glucose, and galactose are all monosaccharides. Thus, the correct answer is: d. all of the above

Key concepts

Carbohydrates

Carbohydrates are essential nutrients found in various foods, playing a crucial role in the human diet. They are organic compounds made of carbon, hydrogen, and oxygen atoms. The general formula can be represented as \( (CH_2O)_n \), where \( n \) typically varies between 3 to 7. Carbohydrates are divided into categories based on the number of sugar units they contain:

• Monosaccharides: Single sugar units, such as glucose, fructose, and galactose.
• Disaccharides: Two sugar units, e.g., sucrose and lactose.
• Polysaccharides: Many sugar units, including starch and cellulose.

Monosaccharides are the simplest carbohydrates serving as building blocks for more complex forms.
They provide immediate energy and are easily absorbed by the body to fuel cells and bodily functions. Understanding carbohydrates can help you make informed dietary choices and comprehend biological processes.

Glucose

Glucose is a vital monosaccharide that serves as a primary energy source for most organisms. It is a simple sugar with the molecular formula \( C_6H_{12}O_6 \).
Produced by plants through photosynthesis, glucose is also synthesized commercially and added to many foods as a sweetener or energy source. In the human body, glucose is crucial for:

• Providing energy to cells, especially brain cells.
• Acting as a fuel during cellular respiration, a process that converts glucose into ATP, the energy currency of the cell.
• Maintaining blood sugar levels through regulation by insulin and glucagon.

Glucose can form polymers such as starch and glycogen, acting as energy storage in plants and animals, respectively. Monitoring glucose levels is important for managing conditions like diabetes.

Fructose

Fructose, known as fruit sugar, is a naturally occurring monosaccharide. It shares the same molecular formula as glucose, \( C_6H_{12}O_6 \),
but has a different structural arrangement leading to different properties.Fructose is primarily found in:

• Fruits and honey, giving them their natural sweetness.
• Certain root vegetables like beets and sweet potatoes.

Though fructose provides energy, its metabolism differs from glucose. It is mainly processed in the liver. High consumption of fructose, particularly from processed foods and sweeteners like high fructose corn syrup, has raised health concerns. It has been linked to issues like obesity and insulin resistance, highlighting the need to consume fructose in moderation.

Galactose

Galactose is also a monosaccharide, similar to glucose and fructose, with the chemical structure \( C_6H_{12}O_6 \).
It is not found in its free form in most foods but is predominantly a component of lactose.Lactose, the sugar in milk, is a disaccharide composed of glucose and galactose. During digestion, lactose is broken down into these monosaccharides by the enzyme lactase. In the human diet, galactose:

• Is primarily consumed through dairy products.
• Provides energy upon metabolism, similar to other sugars.

Some individuals lack sufficient lactase and face lactose intolerance, leading to digestive discomfort when consuming dairy. Galactose can be converted into glucose through metabolic pathways, contributing to energy production in the body.