Lesson 4: Biomolecules-Carbohydrates (Part 1)

Summary

This Grade 10 science lesson, taught by Marian Soriano, covers the essential role of biomolecules, with a focus on carbohydrates. Students learn about the types of carbohydrates—monosaccharides, disaccharides, and polysaccharides—and their functions in energy production and structural support. The lesson also delves into the biochemical tests for detecting carbohydrates, such as Benedict's solution, Fehling’s solution, and the iodine test. With examples like glucose, starch, and cellulose, the lesson highlights how carbohydrates are vital to both plants and animals, making it an informative exploration of an important biological topic.

Takeaways

• 😀 Biomolecules are substances produced by cells and living organisms, with major types including carbohydrates, lipids, nucleic acids, and proteins.
• 😀 Carbohydrates are the most important and readily available source of energy for the body, essential for both children and adults.
• 😀 The general chemical formula for carbohydrates is C6H12O6, representing the ratio of carbon, hydrogen, and oxygen in these biomolecules.
• 😀 Carbohydrates are classified into three categories: monosaccharides (simple sugars), disaccharides (two monosaccharides combined), and polysaccharides (long chains of monosaccharides).
• 😀 Monosaccharides, such as glucose, galactose, and fructose, are simple sugars that play important roles in energy production and metabolism.
• 😀 Disaccharides like sucrose, lactose, and maltose are formed when two monosaccharides undergo a dehydration reaction, resulting in a covalent bond and the release of water.
• 😀 Polysaccharides, such as starch and glycogen, are long chains of monosaccharides and serve as storage forms of energy in plants and animals.
• 😀 Starch, made up of amylose and amylopectin, is the primary energy storage in plants, while glycogen serves as energy storage in humans and other vertebrates.
• 😀 The presence of carbohydrates can be detected using specific test solutions like Benedict's solution, Fehling's solution, and iodine solution.
• 😀 Reducing sugars can be identified by Benedict’s solution (color changes from blue to green, yellow, orange, or red), while iodine solution detects starch by turning black or dark when starch is present.

Q & A

What are nucleic acids and what role do they play in the cell?

Nucleic acids, like DNA and RNA, are important biomolecules that provide instructions for various cell activities. They play a crucial role in storing and transmitting genetic information.

What are biomolecules?

Biomolecules are substances produced by cells and living organisms that perform various functions. These include carbohydrates, lipids, nucleic acids, and proteins.

What are the four major types of biomolecules?

The four major types of biomolecules are carbohydrates, lipids, nucleic acids, and proteins.

Why are carbohydrates important for the body?

Carbohydrates are the body's primary and most readily available source of energy. They are essential for both children and adults as part of a healthy diet.

What is the general chemical formula for carbohydrates?

The general chemical formula for carbohydrates is C6H12O6, which reflects the common ratio of carbon, hydrogen, and oxygen in these molecules.

What are monosaccharides?

Monosaccharides are simple sugars with carbon numbers ranging from three to seven. They are the basic building blocks of carbohydrates.

How are disaccharides formed?

Disaccharides are formed when two monosaccharides undergo a dehydration or condensation reaction, where a water molecule is released and a covalent bond, called a glycosidic bond, is formed.

What is the difference between reducing and non-reducing sugars?

Reducing sugars can be oxidized by mild oxidizing agents due to their free aldehyde or ketone functional group. Non-reducing sugars, like sucrose, do not react with mild oxidizing agents.

What is the iodine test used for?

The iodine test is used to detect the presence of starch (a polysaccharide). A positive result is indicated by a color change to black or dark blue.

What is the significance of glycogen in the human body?

Glycogen is the storage form of glucose in humans and other vertebrates. It is stored in the liver and muscles, and when blood glucose levels drop, glycogen is broken down to release glucose through a process called glycogenolysis.