Carbon and the Molecular Diversity of Life — Campbell Biology Chapter 4

Vocabulary flashcards covering key terms and concepts from carbon chemistry, the carbon cycle, and the functional groups essential for biomolecules.

Carbon cycle

The movement of carbon among the atmosphere, organisms, oceans, and earth, including photosynthesis, respiration, decomposition, and fossil fuel formation.

Carbon dioxide (CO2)

An inorganic gas in the atmosphere; raw material for photosynthesis; greenhouse gas contributing to warming.

Photosynthesis

Process by which photoautotrophs convert light energy and CO2 into organic sugars, storing energy in chemical bonds.

Carbon fixation

Incorporation of CO2 into organic molecules during photosynthesis.

Organic molecules

Carbon-based compounds produced by living organisms; the products of photosynthesis and respiration.

ATP (adenosine triphosphate)

Cellular energy currency; formed from ADP and phosphate; drives most cellular reactions.

Fossil fuels

Coal, oil, and other energy-rich carbon compounds formed from ancient organisms; burning releases CO2.

Greenhouse gas

Gas in the atmosphere (e.g., CO2, methane) that traps heat and warms the planet.

Methane (CH4)

A simple hydrocarbon; potent greenhouse gas with high heat-trapping per molecule.

Hydrocarbons

Molecules composed only of carbon and hydrogen; typically nonpolar and hydrophobic.

Alkane

Saturated hydrocarbons with only single bonds; end in -ane (e.g., methane, ethane).

Methane

The simplest alkane (CH4) with one carbon and four hydrogens; tetrahedral geometry.

Ethane

C2H6; two carbons connected by a single bond; all other bonds to hydrogen.

Ethene (ethylene)

C2H4; an alkene with a carbon–carbon double bond; planar and non-rotatable.

Alkene

Hydrocarbon with at least one double bond; ends with -ene.

Double bond

Bond sharing two pairs of electrons; restricts rotation and changes molecule geometry.

Isomer

Molecules with the same molecular formula but different structures

Structural isomer

Isomers with same formula but different shape due to the way the atoms are linked together

Enantiomer

differ in special arrangement around the central asymmetric carbon

Cis-trans isomer (geometric isomer)

Isomerism around a double bond; cis = same side, trans = opposite sides; affects shape.

Methyl group

CH3 substituent; common side group in organic molecules.

Functional group

groups that change the molecule’s shape, chemistry, and function.

Hydroxyl group

–OH; forms alcohols; makes molecules polar and hydrophilic.

Carbonyl group

C=O; in aldehydes (terminal) or ketones (in the middle); increases polarity.

Aldehyde

Carbonyl group at the end of a carbon skeleton; terminal carbonyl compound.

Ketone

Carbonyl group within the carbon skeleton; internal carbonyl compound.

Carboxyl group

–COOH; acidic group that donates a proton in water, creating polarity.

Amino group

–NH2; acts as a base; present in amino acids; forms peptide bonds.

Sulfhydryl group

–SH; thiol group; can form disulfide bonds that influence protein structure.

Phosphate group

–PO4 (often as –PO4^3– in solution); negative, polar; key in energy transfer (ATP) and DNA backbone.

Methyl group (CH3)

Methyl substituent; modulates function and gene expression via methylation.

DNA sugar-phosphate backbone

Alternating sugar (deoxyribose in DNA, ribose in RNA) and phosphate groups forming the DNA backbone.

Deoxyribose

Five-carbon sugar in DNA; lacks the 2′-OH, differentiating DNA from RNA.

Ribose

Five-carbon sugar in RNA; contains a 2′-OH group.

Nucleic acids

DNA and RNA polymers built from nucleotides; store and transmit genetic information.

Nitrogenous base

Part of a nucleotide (adenine, thymine, cytosine, guanine, uracil); paired in DNA/RNA.

Mitochondria

Organelle where cellular respiration occurs; produces ATP.

Polypeptide

Polymer of amino acids; folds into a protein with specific function.

Amino acids

Monomers of proteins; contain amino and carboxyl groups with a side chain.

Peptide bond

Bond between the amino group of one amino acid and the carboxyl group of the next.

Biological energy transfer

ATP hydrolysis releases energy to drive non-spontaneous biological reactions.

ATP → ADP + Pi

Transfer of a phosphate from ATP to another molecule; energy is released in the process.

Base pairing and nucleotides

Knowledge of how nucleotides with different bases encode genetic information.

Hydrophilic

Molecule or region that interacts well with water due to polarity.

Hydrophobic

Nonpolar molecule or region that tends to repel water.

organic chemistry

the study of compounds that contain carbon, regardless of origin

4 ways carbon chains can vary

length

double bond position

branching

presence of rings