Biomolecules

Biomolecules

Middle School

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Learning Objectives

• Identify the four main types of biomolecules.

• Describe the primary functions of carbohydrates, lipids, proteins, and nucleic acids.

• Name the monomer for each of the four major biomolecules.

• Understand the key roles that biomolecules play in living organisms.

Key Vocabulary

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Carbohydrate

A biomolecule that provides the body with a quick source of short-term energy for activities.

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Lipid

A biomolecule for long-term energy storage, insulation, and forming cell membranes in the body.

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Protein

A biomolecule that provides structure, builds tissue, and speeds up the body's chemical reactions.

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Nucleic Acid

A biomolecule, like DNA or RNA, that stores and expresses an organism's genetic information.

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Monomer

A small, individual molecule that acts as a basic building block for a larger polymer.

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Polymer

A large molecule that is made up of many repeating smaller units called monomers.

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Carbohydrates

• Carbohydrates are the body’s main source of quick, short-term energy.

• They are made of carbon, hydrogen, and oxygen atoms.

• Simple sugars called monosaccharides link together to form large polysaccharides.

• Common examples are glucose, sucrose, and cellulose in foods like pasta.

Multiple Choice

What is the primary function of carbohydrates in living organisms?

• To provide fast, short-term energy

• To store genetic information

• To build and repair tissues

• To provide long-term energy storage

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What are Lipids?

• Lipids store long-term energy and provide insulation to keep the body warm.

• They are essential for forming the structure of every cell membrane.

• Their monomers are glycerol and fatty acids, made from C, H, and O.

• Common examples include foods like oil and butter, as well as steroids.

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Multiple Choice

What are the monomers that make up lipids?

• Glycerol and fatty acids

• Amino acids

• Monosaccharides

• Nucleotides

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What Are Proteins?

• Proteins provide structure and help repair and build the body's tissues.

• ​They help fight diseases and speed up chemical reactions in the body.

• They are made of amino acids linked together by peptide bonds to form polypeptides.

• You can find proteins in foods like meat, fish, eggs, beans, and nuts.

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Multiple Choice

Which monomer units are found in proteins but not in carbohydrates and lipids?

• Amino acids

• Glycerol

• Monosaccharides

• Hydrophilic tails

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Nucleic Acids

• Nucleic acids store and express the genetic information of a living organism.

• They contain Carbon, Hydrogen, Oxygen, Nitrogen, and Phosphorus.

• The monomer of a nucleic acid is a nucleotide, which forms polymers.

• The two main types are DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).

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Multiple Choice

What is the main function of nucleic acids like DNA and RNA?

• Storage and expression of genetic information

• Provide fast, short-term energy

• Speed up chemical reactions

• Make up cell membranes

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Common Misconceptions About Biomolecules

Misconception	Correction
All fats (lipids) are unhealthy.	Lipids are vital for energy, insulation, and are key to cell membranes.
Carbohydrates are just unhealthy sugars.	Carbohydrates are the body's main energy source, found in many healthy foods.
You only need protein to build muscles.	Proteins also fight diseases and speed up chemical reactions as enzymes.
All biomolecules are made of the same elements.	Proteins also contain Nitrogen (N), and nucleic acids contain N and Phosphorus (P).

Multiple Choice

An athlete is preparing for a marathon, a long-distance race. Which two biomolecules will be most important for providing long-term energy storage and muscle repair after the race?

• Lipids and Proteins

• Carbohydrates and Nucleic Acids

• Lipids and Carbohydrates

• Proteins and Nucleic Acids

Multiple Choice

How are the functions of carbohydrates and lipids different, even though both are primarily composed of carbon, hydrogen, and oxygen?

• Carbohydrates provide quick energy, while lipids provide long-term energy storage.

• Carbohydrates store genetic info, while lipids build tissues.

• Carbohydrates speed up reactions, while lipids provide insulation.

• Carbohydrates form cell membranes, while lipids provide quick energy.

Multiple Choice

A newly discovered organism's cells are found to be unable to store and transmit its genetic information. A defect in which biomolecule is the most likely cause of this issue?

• Nucleic Acids

• Proteins

• Lipids

• Carbohydrates

Multiple Choice

If a person's diet was completely lacking in foods that contain nitrogen, what would be the most direct consequence for their body's ability to function?

• The inability to build and repair tissues or produce enzymes.

• The inability to store short-term energy.

• The inability to form cell membranes.

• The inability to store long-term energy.

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Summary

• Carbohydrates are for short-term energy; lipids are for long-term storage.

• Proteins build tissues, fight disease, and help chemical reactions as enzymes.

• Nucleic acids like DNA and RNA store and express genetic information.

• Proteins have nitrogen, and nucleic acids have nitrogen and phosphorus.

Poll

On a scale of 1-4, how confident are you about the concepts covered in today's review?

• 1

• 2

• 3

• 4