Introduction to Biomolecules

Introduction to Biomolecules

• Unit 1 introduces cells and biomolecules. Biomolecules are the focus.

Learning Objectives

• Describe the structures and the properties of proteins
• Describe the structures the properties of nucleic acids (DNA and RNA)
• Describe the structures the properties of carbohydrates
• Describe the structures the properties of lipids
• Explain how these structures and their properties relate to their roles in organisms
• Use knowledge to solve related problems

What are Biomolecules?

• Living organisms are made of biomolecules.
• Biomolecules are organic compounds containing carbon and hydrogen.
• Biomolecules include lipids, nucleic acids, carbohydrates and proteins.

Inorganic Vs Organic Compounds

• Inorganic compounds typically have cations and anions and are ionically bonded, having few atoms and associated with non-living matter.
• Biomolecules always contain carbon and hydrogen, are covalently bonded, are quite large with many atoms, and are usually associated with living systems.

Carbon, The Backbone of Life

• Carbon is the fourth most abundant element in the universe and the building block of life.
• All living things contain carbon.
• Carbon exists in many forms including cellulose and chlorophyll.

Carbon's Bonding Versatility

• Carbon is special due to its ability to form a maximum of four bonds.
• Carbon bonds with other carbon atoms and elements like nitrogen, hydrogen, and oxygen.
• It can form long chains like octane and ring structures like cyclohexane.

Biomolecules as Polymers

• A polymer is a large molecule (macromolecule) with repeating subunits known as monomers.

Synthesis and Breakdown of Polymers

• Dehydration/Condensation is the removal of a water molecule that forms a polymer by connecting monomers together. This requires enzymes and energy.
• Hydrolysis is the addition of water molecule and disassembles polymers into monomers, requiring enzymes.

Importance of Biomolecules

• Biomolecules store energy.
• Biomolecules form cell membranes.
• Biomolecules provide structural support.
• Biomolecules help control chemical reactions in organisms
• Biomolecules store hereditary information

1. Carbohydrates

• Carbohydrates Function as energy storage, materials for building biomolecules, and components of cells.

Classes of Carbohydrates

• Monosaccharides are single sugar molecules with 3-7 carbons, and examples are glucose, fructose, and deoxyribose.
• Disaccharides are two monosaccharides joined through dehydration, such as lactose which consists of glucose and galactose, and sucrose as glucose and fructose.
• Polysaccharides are complex polymers of monosaccharides such as Glycogen (animals, as energy storage), Starch (plants, as energy storage). Cellulose (plants, as structural support) and Chitin (insects, crab, as protective coating)

2. Lipids

• Lipids are fatty acids, consisting of long-chained hydrocarbon molecules with a carboxylic acid (-COOH) functional group.
• Lipids are not polymers, formed through dehydration and broken down through hydrolysis, the compound includes greasy or oily compounds, insoluble in water.
• Lipid examples are triglycerides, phospholipids, cholesterols, and steroids. 

Types of Lipids

• Triglycerides have a glycerol bonded to 3 fatty acid chains, storing energy, insulate (fat tissues under skin), and cushion (organs and tissues; "shock absorbers").
• Phospholipids have a glycerol, linked to a phosphate group and to 2 fatty acid chains, and it is used as a main component of cell membrane.
• Cholesterol has 4 interconnected carbon rings that stabilize cell membranes, synthesizes hormones and digestion.

Saturated vs. Unsaturated Fatty Acids

• Saturated Fat (butter) have no double bonds, solid at room temperature, and comes from animals.
• Unsaturated Fat (oil) has one or more double bonds, is liquid at room temperature, and originates from plants.
• The type of hydrocarbon tails affect the fluidity of plasma membrane. Winter wheat has higher percentage of unsaturated phospholipids.
• Saturated fat intake can be bad for heath.

3.Proteins

• The "building block of the body"
• A typical human cell codes for up to 30,000 different types of proteins.
• It consists of C, H, O, and N elements

Protein Function

• Mechanical support /movement – Collagen, muscles.
• Enzymes – biological catalyst.
• Transport – Hemoglobin; membrane proteins.
• Defense - antibodies.
• Body regulatory – hormones.
• Support - Keratin, collagen.

Melamine Warning

• Melamine is an industrial chemical abused by food producers.

Polymers of Amino Acids

• Amino acids are building blocks of proteins joined together via a peptide bonds that forms a polypeptide chain.
• Each protein contains anywhere from 20 to over 1000.

Amino Acid Structure

• Amino acids are joined via peptide bonds
• Note. the Carboxyl group is the same group as that found in fatty acids and it makes amino acids acidic.

Types of Amino Acids

• Some amino acids are neutral with non-polar side chains
• Some amino acids are neutral with polar side chains.
• Some are positively-charged.
• Some are negatively-charged

Synthesis and Degradation of a Protein

• Proteins are linear polymers of amino acids.
• The carboxyl group of one amino acid is linked to the amino group of another amino acid.
• The reaction is a dehydration as water is released.

From Amino Acids To Functional Proteins

• Different amino acid molecules join head-to-tail to form a polypeptide
• A polypeptide folds into a 3D functional protein.
• Different proteins have different amino acid sequences

Protein 3D Structure

• All proteins need to be folded into a defined 3D conformation/ shape to perform their functions.

Levels of Protein Folding

• Primary Structure is amino acids held by peptide bonds.
• Secondary Structure involves interaction of groups in the peptide backbone to form alpha helix or beta sheet.
• Tertiary Structure is the folded shape of the polypeptide chain.
• Quaternary Structure is interactions between multiple polypeptide subunits.

Protein Conformation

• Each type of protein has a three-dimensional structure which is determined by the order of the amino acids in its chain, with globular or fibrous structure.

Protein Denaturation

• Denaturation changes the shape of a protein which may involve complete unfolding, causing the protein to lose its function.
• Peptide bonds remain while hydrogen bonds are disrupted, causing the protein to unfold into a random coil and become irreversibly coagulated.
• Denaturation of proteins is caused by a change in salt concentration, pH, temperature, or detergents.

This resource introduces cells and biomolecules, focusing on the structure and properties of proteins, nucleic acids (DNA and RNA), carbohydrates, and lipids. Learn how their structures relate to their roles in organisms and apply this knowledge to solve related problems. Biomolecules are organic compounds essential for living organisms.