Campbell Biology Chapter 4: Carbon and Molecular Diversity

Vocabulary flashcards covering the key concepts, carbon bonding characteristics, isomers, functional groups, and ATP from Chapter 4 of Campbell Biology.

Organic compounds

Chemical compounds containing carbon, which most frequently form covalent bonds with hydrogen, oxygen, nitrogen, or other carbon atoms.

Valence

The bonding capacity of an atom, equal to the number of unpaired electrons in its valence shell; for Hydrogen valence = 1, Oxygen valence = 2, Nitrogen valence = 3, and Carbon valence = 4.

Carbon skeleton variations

The four main structural ways carbon backbones differ: (a) Length, (b) Branching, (c) Double bond position, and (d) Presence of rings.

Hydrocarbon

An organic molecule consisting solely of carbon and hydrogen atoms.

Lipids

Hydrocarbon molecules (such as fats) that can be broken down to provide energy to the cell.

Ethylene bonding structure

A arrangement where each carbon is bonded to three atoms because 2 of its 4 valence electrons are utilized in a double bond with the other carbon, leaving 2 electrons to bond with other atoms.

Isomer

Molecules that share the exact same chemical formula (number and types of atoms) but differ in structure, chemical properties, and behavior.

Structural isomers

Isomers that differ in the covalent arrangements of their atoms, such as pentane and 2-methylbutane.

Cis-trans isomers

Isomers that differ in spatial arrangements around inflexible double bonds; cis isomers have identical groups on the same side, while trans isomers have them on opposite sides.

Functional groups

Specific chemical groups attached to organic molecules that participate in chemical reactions and give the compound its unique biological function.

Estradiol vs. Testosterone

Steroid hormones sharing the same four-ring carbon skeleton, where Estradiol has a hydroxyl group ($\text{-OH}$) and Testosterone has a methyl ($\text{-CH}_3$) and a carbonyl group ($\text{C=O}$), causing them to bind different receptors.

Hydroxyl group ($\text{-OH}$)

A chemical group forming alcohols (e.g., ethanol); polar due to oxygen, forms hydrogen bonds with water, and helps dissolve polar or ionic compounds.

Carbonyl group ($\text{>C=O}$)

A chemical group forming ketones (when located within a carbon skeleton, e.g., acetone) or aldehydes (when at the end of the carbon skeleton, e.g., propanal).

Carboxyl group ($\text{-COOH}$)

A chemical group forming carboxylic acids (e.g., acetic acid); acts as an acid by donating $\text{H}^+$ because the covalent bond between oxygen and hydrogen is highly polar.

Amino group ($\text{-NH}_2$)

A chemical group forming amines (e.g., glycine); acts as a base by picking up $\text{H}^+$ from its surrounding environment.

Sulfhydryl group ($\text{-SH}$)

A chemical group forming thiols (e.g., cysteine); can react to form covalent cross-links that help stabilize protein structure.

Phosphate group ($\text{-OPO}_3^{2-}$)

A chemical group forming organic phosphates (e.g., glycerol phosphate); contributes a negative charge to a molecule and reacts with water to release energy.

Methyl group ($\text{-CH}_3$)

A chemical group forming methylated compounds (e.g., 5-methyl cytosine); affects gene expression when attached to DNA or to proteins bound to DNA.

Adenosine Triphosphate (ATP)

An organic molecule composed of adenosine attached to three phosphate groups; reacts with water to release energy via the reaction $\text{ATP} \rightarrow \text{ADP} + \text{P}_i + \text{Energy}$.