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Reviewer: Chemical Basis of Life

Basic Chemistry:

  • Chemistry is concerned with the atomic composition, structure of substances, and the reactions they undergo.

Matter, Mass, and Weight:

  • Matter refers to anything that occupies space and has mass.
  • Mass is the amount of matter in an object, measured in kilograms.
  • Weight is the gravitational force acting on an object.

Elements and Atoms:

  • An element is the simplest type of matter that has unique properties.
  • An atom is the smallest particle of an element.

Atomic Structure:

  • Atoms consist of neutrons (no electrical charge), protons (positive charges), and electrons (negative charges).
  • The nucleus is formed by protons and neutrons, while electrons are found in the electron cloud.

Electrons and Chemical Bonding:

  • Chemical bonding involves the transfer or sharing of electrons between atoms.
  • Ionic bonds involve the transfer of electrons, while covalent bonds involve the sharing of electrons.
  • Polar covalent bonds have unequal sharing of electrons, resulting in asymmetrical electrical charge.
  • Nonpolar covalent bonds have equal sharing of electrons and symmetrical electrical charge.

Hydrogen Bonds:

  • Weak attractions between the oppositely charged regions of polar molecules.

Molecules and Compounds:

  • A molecule consists of two or more atoms that are chemically combined.
  • A compound consists of two or more different types of atoms that are chemically combined.

Dissociation:

  • The separation of ions in an ionic compound by polar water molecules.
  • Electrolytes are substances that dissociate into ions.

Chemical Reactions:

  • Substances interact to form or break chemical bonds.
  • Reactants are substances that enter into a chemical reaction, while products are the resulting substances.
  • Classification of chemical reactions includes synthesis, decomposition, and exchange reactions.
  • Anabolism refers to synthesis reactions, while catabolism refers to decomposition reactions.
  • Metabolism involves both anabolic and catabolic reactions in the body.

Reversible Reactions:

  • Reactants can form products, and products can form reactants.

Energy and Chemical Reactions:

  • Energy is the capacity to do work.
  • Potential energy is stored energy, while kinetic energy is energy caused by movement.
  • Chemical energy is a form of potential energy stored in chemical bonds.

Rate of Chemical Reactions (RCTC):

  • Factors affecting the rate of chemical reactions include reactants, concentration, temperature, and catalysts.

Acids and Bases:

  • Acids are proton donors, while bases are proton acceptors.

The pH Scale:

  • The pH scale indicates the H+ concentration of a solution.
  • Neutral solutions have an equal number of H+ and OH- ions, with a pH of 7.0.
  • Acidic solutions have a higher H+ concentration and a pH less than 7.0.
  • Basic solutions have a lower H+ concentration and a pH greater than 7.0.
  • The normal pH range of blood is 7.35-7.45.

Salts:

  • Salts are formed when an acid reacts with a base.

Buffer:

  • Buffers are chemicals that resist changes in pH.

Inorganic Molecules:

  • Inorganic molecules do not contain carbon.

Organic Molecules:

  • Organic molecules contain carbon.

Carbohydrates:

  • Carbohydrates consist of carbon, hydrogen, and oxygen.
  • Monosaccharides are the smallest carbohydrates, such as glucose and fructose.
  • Disaccharides are composed of two monosaccharides, such as sucrose.
  • Polysaccharides consist of many monosaccharides, such as glycogen, starch, and cellulose.

Lipids:

  • Lipids are substances that dissolve in nonp

olar solvents.

  • They consist of carbon, hydrogen, oxygen, phosphorus, and nitrogen.
  • Fats are important energy-storage molecules, and triglycerides are the most common type.
  • Saturated fatty acids have single covalent bonds, while unsaturated fatty acids have double covalent bonds.
  • Phospholipids have a polar hydrophilic end and a nonpolar hydrophobic end.
  • Eicosanoids are regulatory molecules derived from fatty acids.
  • Steroids have carbon atoms arranged in ring-like structures, including cholesterol.

Proteins:

  • Proteins consist of carbon, hydrogen, oxygen, nitrogen, and sulfur.
  • They regulate chemical reactions, serve as structural components, and cause muscle contraction.
  • Amino acids are the building blocks of proteins, with 20 basic types.
  • Denaturation occurs when proteins change shape due to high temperature or pH.
  • Enzymes are protein catalysts that lower the activation energy.
  • The lock-and-key model explains how enzymes bind to specific reactants.

Nucleic Acids: DNA and RNA:

  • DNA is the genetic material of cells, and RNA plays a role in gene expression/protein synthesis.
  • Nucleic acids are large molecules composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus.
  • Nucleotides are the basic building blocks of DNA and RNA.

Adenosine Triphosphate (ATP):

  • ATP is an important organic molecule and the energy currency of cells.
  • It stores and provides energy for cellular processes.

Overall, this review provides an overview of the chemical basis of life, covering topics such as basic chemistry, atomic structure, chemical bonding, reactions, acids and bases, organic and inorganic molecules, and important biomolecules like carbohydrates, lipids, proteins, and nucleic acids.