Overview
This practice test covers key concepts in the chemistry of life, focusing on the importance of carbon, isomerism, hydrocarbons, functional groups, and ATP.
Chemical Elements of Life
- The six most important elements of life are carbon, nitrogen, oxygen, hydrogen, phosphate, and sulfur.
Organic Molecules and Stanley Miller's Experiments
- Miller's volcanic simulation reanalysis identified additional organic compounds not found in his original experiment.
- Miller's classic experiment demonstrated that simple organic compounds can be synthesized from components in Earth's primitive atmosphere.
- CH₄ (methane) is an example of an organic molecule.
Carbon Structure and Isomerism
- Carbon bonded to four atoms forms a tetrahedral shape.
- The presence of enantiomers (isomers from an asymmetric carbon) can make drugs toxic or effective.
- A straight-chain compound with 6 hydrogen and 2 carbon atoms must have a carbon-carbon double bond.
- Carbon atoms are versatile because each can bond in four directions, allowing branching.
- Carbon has 4 valence electrons.
- Hydrocarbons are hydrophobic, nonpolar, and store energy.
- A molecule with one C=C double bond and four monovalent atoms can have two cis-trans isomers.
- Two compounds can be hydrocarbons, isomers, organic, and double-bonded.
Biological Importance of Isomers and Enantiomers
- Using only one enantiomer is important because one may be effective while the other is ineffective or toxic.
Functional Groups and Amino Acids
- All amino acids contain an amino group (NH₂) and a carboxyl group (COOH).
- Ethanol, propanol, and methanol all have a hydroxyl functional group and are water-soluble.
- The carboxyl group is written as RCOOH.
- Functional groups like COH, COOH, and OH increase water solubility.
- The covalent bond in carboxyl groups is so polar that hydrogen ions dissociate reversibly.
Energy and Functional Groups
- The phosphate group releases energy when removed with water.
- Abscisic acid contains a carboxyl group.
- Hydroxyl, carboxyl, and amino groups can hydrogen bond with oxygen atoms in other groups.
- The sulfhydryl group (SH) is characteristic of thiols.
ATP and Cellular Energy
- ATP stores potential energy; removing a phosphate group by adding water releases energy for cellular use.
Key Terms & Definitions
- Organic molecule — A molecule containing carbon, usually bonded to hydrogen.
- Isomer — Compounds with the same formula but different structures.
- Enantiomer — Isomers that are mirror images of each other.
- Hydrocarbon — Organic molecules consisting entirely of carbon and hydrogen.
- Functional group — Specific groups of atoms within molecules that determine chemical properties.
- Amino group (NH₂) — Functional group found in all amino acids.
- Carboxyl group (COOH) — Functional group found in all amino acids.
- Hydroxyl group (OH) — Functional group characteristic of alcohols.
- Sulfhydryl group (SH) — Functional group characteristic of thiols.
- ATP — Adenosine triphosphate, the primary energy carrier in cells.
Action Items / Next Steps
- Review functional groups and their properties.
- Study the role of carbon in biological molecules.
- Practice identifying isomers and enantiomers.
- Prepare for questions on ATP and cellular energy.