Chapter 4: Chemistry of Life

Elements

Substances that cannot be broken down into simpler substances by chemical means.

Trace Elements

Trace elements are chemical elements that are required in very small amounts by living organisms for proper physiological and biochemical functioning.

Atoms

The basic unit of matter consisting of a nucleus of positively charged protons and neutrally charged neutrons, surrounded by negatively charged electrons.

Nucleus

The center of an atom that contains positively charged protons and neutrally charged neutrons.

Electrons

Negatively charged particles that orbit the nucleus of an atom.

Protons

Positively charged particles that are found in the nucleus of an atom.

Neutrons

Neutrally charged particles that are found in the nucleus of an atom.

Atoms

The basic unit of matter that consists of a nucleus made up of protons and neutrons, surrounded by electrons.

Compounds

A substance made up of two or more different elements chemically combined in a fixed ratio.

Ionic Bond

A type of chemical bond that involves the transfer of electrons from one atom to another, resulting in the formation of oppositely charged ions that attract each other and form a stable compound.

Covalent Bond

A chemical bond that involves the sharing of electrons between atoms, resulting in the formation of a stable molecule.

Hydrogen bonds

A type of chemical bond that forms between a partially positively charged hydrogen atom and a partially negatively charged atom, such as nitrogen, oxygen, or fluorine, in another molecule. These bonds are important in many biological processes, including the structure of DNA and the folding of proteins.

Carbohydrates

A type of macronutrient that is the primary source of energy for the body, composed of carbon, hydrogen, and oxygen molecules.

Monosaccharides

Simple sugars that cannot be broken down into smaller sugars.

Disaccharides

A type of carbohydrate made up of two monosaccharides (simple sugars) joined together through a glycosidic bond. Examples include sucrose, lactose, and maltose.

Polysaccharides

Polysaccharides are complex carbohydrates made up of long chains of monosaccharides (simple sugars) linked together by glycosidic bonds. They serve as a source of energy and structural support in living organisms, and include important molecules such as starch, glycogen, and cellulose.

Proteins

Large biomolecules made up of chains of amino acids that perform various functions in the body, such as building and repairing tissues, transporting molecules, and catalyzing metabolic reactions.

Lipids

Organic compounds that are insoluble in water but soluble in nonpolar solvents. They include fats, oils, waxes, phospholipids, and steroids.

Phospholipids

A type of lipid that is the main component of cell membranes. They have a hydrophilic (water-loving) head and a hydrophobic (water-fearing) tail, which allows them to form a lipid bilayer.

Cholesterol

A type of steroid that is found in cell membranes and is a precursor for the synthesis of other steroids, such as sex hormones. High levels of cholesterol in the blood are associated with an increased risk of heart disease.

Polypeptides

Chains of amino acids that are the building blocks of proteins.

Nucleic acids

Molecules made up of nucleotides that carry genetic information.

DNA

A type of nucleic acid that contains the genetic information for all life.

RNA

A type of nucleic acid that is essential for protein synthesis.

Acids

A solution is acidic if it contains a lot of hydrogen ions (H+).