Carbon Compounds and Biological Macromolecules

Vocabulary flashcards covering organic chemistry, biological polymers, carbohydrates, lipids, protein structural levels, and nucleic acid properties.

Organic Compounds

Carbon-containing chemical compounds that form the basis of living organisms, frequently combined with elements such as hydrogen, oxygen, sulfur, phosphorus, and nitrogen.

Macromolecules

Large, complex molecules present in living organisms that fall into four major biological categories: carbohydrates, lipids, proteins, and nucleic acids.

Hydrocarbon

An organic molecule consisting solely of carbon and hydrogen atoms, which is nonpolar and capable of storing large quantities of energy.

Functional Group

Specific chemical groups attached to molecular structures that directly participate in chemical reactions and influence molecular function.

Polymer

A long molecule made up of many similar or identical repeating structural units joined together by covalent bonds.

Monomer

The repeating molecular subunit that serves as the building block for constructing larger polymer chains.

Dehydration Reaction

A reaction that links monomers together by forming a covalent bond while releasing a water molecule through the removal of two hydrogen atoms and one oxygen atom.

Hydrolysis

A chemical process that breaks down polymers into monomers by inserting a water molecule, attaching a hydrogen atom to one monomer and a hydroxyl group ($\text{OH}$) to the other.

Monosaccharide

The basic monomer unit of carbohydrates having a molecular formula that is a multiple of $\text{CH}_2\text{O}$ ($1:2:1$ ratio of $\text{C:H:O}$), with glucose ($\text{C}_6\text{H}_{12}\text{O}_6$) being the most common.

Glycosidic Linkage

A covalent bond formed between two monosaccharide units through a dehydration reaction.

Disaccharide

A double sugar molecule consisting of two monosaccharides linked together by a glycosidic linkage, such as sucrose, maltose, or lactose.

Polysaccharide

A polymer formed by linking hundreds to thousands of monosaccharides via glycosidic linkages, functioning as energy storage or structural support.

Starch

A storage polysaccharide in plants composed of glucose monomers that serves as a reservoir of stored energy.

Glycogen

An extensively branched glucose polysaccharide stored in animal liver and muscle tissue that breaks down via hydrolysis to release energy on demand.

Cellulose

An unbranched structural glucose polymer found in plant cell walls that is non-digestible by humans and functions as dietary insoluble fiber.

Chitin

A structural polysaccharide utilized by arthropods to construct exoskeletons and by fungi to build cell walls.

Lipids

A group of biological compounds defined by their hydrophobic nature and insolubility in water, including fats, phospholipids, and steroids.

Triacylglycerol

A fat molecule constructed from three fatty acid chains attached to a glycerol backbone through ester linkages.

Saturated Fat

A fat molecule possessing no double bonds between carbon atoms, allowing hydrocarbon chains to pack tightly so that it remains solid at room temperature.

Unsaturated Fat

A fat molecule containing one or more double bonds that create kinks in the hydrocarbon chains, preventing close packing and maintaining a liquid state at room temperature.

Phospholipid

A lipid composed of a glycerol bound to two hydrophobic fatty acid tails and one hydrophilic phosphate head group, forming the structural basis of cell membranes.

Steroid

A type of lipid defined by a molecular framework consisting of four fused carbon rings.

Cholesterol

An essential steroid in animal cell membranes that serves as a precursor for other steroids, though high levels in diet and liver synthesis can lead to atherosclerosis.

Amino Acid

An organic molecule containing a central alpha carbon bonded to an amino group, a carboxyl group, a hydrogen atom, and a variable side chain ($\text{R}$ group).

Polypeptide

An unbranched polymer chain made of amino acids linked together by peptide bonds.

Peptide Bond

The covalent bond that joins the carboxyl end of one amino acid to the amino group of another via a dehydration reaction.

Primary Protein Structure

The specific linear sequence of amino acids in a polypeptide chain, encoded by genetic instructions.

Secondary Protein Structure

Localized folds and coils within a polypeptide chain, such as alpha helices and beta pleated sheets, stabilized by hydrogen bonds along the backbone.

Tertiary Protein Structure

The overall three-dimensional shape of a single polypeptide chain held together by interactions among side chains ($\text{R}$ groups), including disulfide bridges.

Quaternary Protein Structure

The overall functional protein structure formed by the association and aggregation of two or more individual polypeptide subunits.

Denaturation

The unravelling and loss of function of a protein caused by environmental disruptions (such as extreme temperature, pH, or salt changes) that break weak chemical bonds.

Nucleic Acid

A polymer made of nucleotide monomers (such as DNA or RNA) responsible for carrying genetic instructions and guiding protein production.

Nucleotide

The repeating monomer unit of nucleic acids, consisting of a nitrogenous base, a five-carbon pentose sugar, and one to three phosphate groups.

Pyrimidine

A nitrogenous base category composed of a single six-membered ring of carbon and nitrogen atoms, which includes cytosine, thymine, and uracil.

Purine

A nitrogenous base category featuring a six-membered ring fused to a five-membered ring, which includes adenine and guanine.

Deoxyribose

The pentose sugar present in DNA nucleotides that lacks an oxygen atom on the second carbon atom of its ring structure.

Ribose

The pentose sugar present in RNA nucleotides that contains a hydroxyl group attached to its second carbon ring position.

Phosphodiester Linkage

A covalent bond linking the sugar of one nucleotide to the phosphate group of another to construct the sugar-phosphate backbone of a nucleic acid.

Antiparallel

The structural arrangement of the two complementary strands in a DNA double helix running in opposite $5' \rightarrow 3'$ directions.