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General Biology: Carbon and Functional Groups

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  • What is an isomer?

    Isomers are molecules with the same molecular formula but different structures and properties.

  • Why are C, H, O, and N the most common elements in living things?

    They make up 96% of living matter due to their ability to form diverse and stable bonds essential for life.

  • What feature of carbon gives it the ability to form large, complex molecules?

    Carbon has 4 valence electrons and 4 valences, allowing it to form up to 4 covalent bonds with diverse atoms including itself.

  • What is a functional group?

    A functional group is a specific group of atoms attached to a carbon skeleton that participates in chemical reactions and gives molecules unique properties.

  • Name the seven major functional groups important in biology.

    Hydroxyl, Carbonyl, Carboxyl, Amino, Phosphate, Sulfhydryl, and Methyl groups.

  • How do carbon skeletons vary?

    They vary in length, branching, double or triple bonds, and ring structures, contributing to molecular diversity and complexity.

  • How to differentiate aldehydes and ketones?

    Aldehydes have a carbonyl group at the end of the carbon skeleton; ketones have it within the skeleton.

  • Which functional groups become ionized under cellular conditions?

    Carboxyl groups act as acids and amino groups act as bases, becoming ionized in cells.

  • Which functional group does not improve solubility?

    The methyl group (-CH3) is nonpolar and does not improve solubility in water.

  • What are structural isomers?

    Isomers with different covalent arrangements of atoms.

  • What are cis-trans isomers?

    Isomers with the same covalent bonds but differ in spatial arrangement around a double bond; cis groups on same side, trans on opposite sides.

  • What are enantiomers?

    Mirror-image isomers with four different groups attached to a carbon; often one is biologically active and the other inactive.

  • What is the role of the hydroxyl group (-OH)?

    It increases solubility and is characteristic of alcohols.

  • Describe the carbonyl group (>C=O).

    A carbon double bonded to oxygen; aldehydes have it at the end, ketones within the carbon skeleton.

  • Describe the carboxyl group (-COOH).

    A carbon double bonded to oxygen and single bonded to hydroxyl; acts as an acid in cells.

  • Describe the amino group (-NH2).

    A nitrogen bonded to two hydrogens; acts as a base under cellular conditions.

  • Describe the phosphate group (-OPO3^2-).

    A phosphorus atom bonded to four oxygens; contributes negative charge and is part of DNA, membranes, and energy molecules.

  • Describe the sulfhydryl group (-SH).

    A sulfur bonded to hydrogen; helps stabilize protein structure by forming covalent bonds.

  • Describe the methyl group (-CH3).

    A carbon bonded to three hydrogens; affects gene expression but does not improve solubility.

  • How does changing functional groups affect molecules?

    It changes the molecule's properties and function, e.g., male and female sex hormones differ only in functional groups.