Biology Chapter: Organic Compounds

The Chemistry of Life: Organic Compounds

• Organic compounds are chemical substances making up organisms and aiding life processes.
• All organic compounds contain carbon and hydrogen.
• Carbon is the central element in organic molecules; without it, life as we know it would cease to exist.

Lesson Objectives

• Carbon's essential role in life on Earth is explained.
• Structures and functions of carbohydrates, lipids, proteins, and nucleic acids are described.

Introduction

• Organic compounds form the basis of life.
• They are involved in all life processes.

The Significance of Carbon

• Nearly 10 million carbon-containing organic compounds are known.
• Carbon compounds in organisms include carbohydrates, lipids, proteins, and nucleic acids.
• Carbon bonds with various elements, forming large, complex molecules.
• Bonds include single, double, and triple bonds with other carbon atoms and other elements.

Carbohydrates

• Carbohydrates contain carbon, hydrogen, and oxygen.
• They are the most common type of organic compound.
• They are made of one or more monosaccharides (simple sugars).
  • Simple carbohydrates are found in fruits, milk, and vegetables; examples include cake, candy, and refined sugars.
  • Simple carbohydrates provide energy, but often lack vitamins, minerals, and fiber.
  • Complex carbohydrates are found in breads, legumes, rice, pasta, and starchy vegetables.
  • They provide vitamins, minerals, and fiber in addition to energy.

Monosaccharides and Disaccharides

• Common monosaccharides include glucose and fructose
• Two monosaccharides bonded together form a disaccharide, e.g., sucrose (table sugar)
• Monosaccharides and disaccharides are known as simple sugars.
• They provide energy to living cells.

Polysaccharides

• Two or more monosaccharides form a polysaccharide.
• Polysaccharides may contain several thousand monosaccharides.
• Main functions are energy storage and structural tissues (cell walls, exoskeletons).

The Compounds of Life

Lipids

• Lipids contain carbon, hydrogen, and oxygen.
• Lipids include fats, oils, and waxes.
• Lipid molecules consist of glycerol and three fatty acids.
• Lipids are hydrophobic (non-polar).
• Several types of lipids can consist of additional molecules.
  • Triglycerides are the main form of stored energy in animals.
  • Phospholipids are major components of cell membranes.
  • Steroids have a variety of functions, including components of cell membranes (cholesterol) and hormones (male and female sex hormones).

Saturated Fatty Acids

• Saturated fatty acids are solids at room temperature.
• Hydrogen atoms surround each carbon atom.
• They form straight chains packed tightly.

Unsaturated Fatty Acids

• Unsaturated fatty acids are liquids at room temperature.
• Some carbon atoms are bonded to fewer hydrogen atoms.
• They form bent chains, not packed tightly.

Lipids and Diet

• Humans need lipids for energy and forming cell membranes.
• Essential fatty acids (omega-3s and omega-6s) must be obtained from food.
• Excess dietary lipids can be harmful, leading to weight gain and cardiovascular disease.

Proteins

• Proteins contain carbon, hydrogen, oxygen, and nitrogen.
• Proteins are made of smaller units called amino acids.
• 20 different common amino acids compose proteins.
• Proteins can have just a few or several hundred amino acids.
• Proteins play many essential roles in organisms — providing structure, speeding up chemical reactions, transporting materials, and defending against disease.
• Proteins bond with other molecules tightly.

Amino Acid Structure

• Amino acids share a basic structure.
• They have a 'R' group, an amino group (NH2), and a carboxyl group (COOH).

Protein Structure

• Amino acids bond together to form peptides and polypeptides.
• Proteins can be composed of one or more polypeptide chains.

Proteins and Diet

• Dietary proteins break down into amino acids for use in building new proteins.
• Humans can synthesize most amino acids, but eight are essential and must come from food.

Protein Denaturation

• Protein denaturation is a change in protein shape, disrupting function.
• Denaturation can be caused by extreme conditions such as heat, acidity, or force.

Nucleic Acids

• Nucleic acids contain carbon, hydrogen, oxygen, nitrogen, and phosphorus.
• Nucleic acids are made of smaller units called nucleotides.
• Nucleic acids are found in all living cells and viruses.
• Types of nucleic acids include DNA and RNA.

Structure of Nucleic Acids

• Nucleic acids consist of one or two chains of nucleotides.
• Each nucleotide has a base, a sugar, and a phosphate group.
  • DNA bases: Adenine, Guanine, Cytosine, Thymine
  • RNA bases: Adenine, Guanine, Cytosine, Uracil
  • The sugar in DNA is deoxyribose; in RNA, it is ribose.

Role of Nucleic Acids

• The order of bases in nucleic acids is significant.
• Base sequences form genetic codes that determine protein structures.
• Information is passed along during cell division and reproduction.

How RNA Codes for Proteins

• DNA provides the genetic blueprint for protein assembly.
• RNA uses DNA information to assemble amino acids into proteins.

Explore the essential role of organic compounds in life processes. This quiz delves into the significance of carbon and the structures and functions of carbohydrates, lipids, proteins, and nucleic acids. Test your understanding of how these compounds form the basis of life on Earth.