Unit 1: Chemistry of Life Flashcards

Comprehensive vocabulary flashcards covering Unit 1: Chemistry of Life, including the chemical properties of water, carbon versatility, isomers, functional groups, and the four major classes of biological macromolecules.

Dihydrogen Monoxide

The chemical name for water ($\text{H}_2\text{O}$), which makes up $70\text{--}95\%$ of most living cells.

Cohesion

The attraction between like molecules; in liquid water, water molecules stick to other water molecules due to hydrogen bonding.

Adhesion

The attraction between different types of molecules; in water, it occurs when water molecules hydrogen-bond to other polar or charged substances.

Capillary Action

The upward movement of water through narrow tubes lined with polar or charged molecules as a result of combined adhesion and cohesion.

Surface Tension

A measure of how difficult it is to stretch or break the surface of a liquid, which is exceptionally high in water due to hydrogen bonding.

Specific Heat

The amount of heat required to raise the temperature of $1\,\text{g}$ of a substance by $1^\circ\text{C}$.

Heat of Vaporization

The quantity of heat a liquid must absorb for $1\,\text{g}$ of it to convert from a liquid state to a gaseous state.

Evaporative Cooling

The process in which the water molecules with the greatest kinetic energy escape as gas, leaving the remaining liquid water cooler.

Solvent

The dissolving agent in a solution, present in the greater quantity.

Solute

The substance that is dissolved in a solution, present in the lesser quantity.

Solution

A homogeneous mixture composed of two or more substances.

Hydrophilic

Water-loving materials that readily dissolve in water because they possess ionic or polar covalent regions capable of forming hydrogen bonds.

Hydrophobic

Water-fearing materials that repel water because they consist of non-polar covalent bonds, such as lipids.

Molarity

A measure of solution concentration defined as the number of moles of solute per liter of solution ($M = \frac{n}{V}$).

Mole

An amount of a substance equal to its molecular weight in grams, containing Avogadro's number ($6.02 \times 10^{23}$) of molecules.

Acid

A substance that increases the hydrogen ion ($\text{H}^+$) concentration of a solution.

Base

A substance that reduces the hydrogen ion ($\text{H}^+$) concentration of a solution, often by releasing hydroxide ions ($\text{OH}^-$) or absorbing $\text{H}^+$.

pH Scale

A logarithmic scale representing hydrogen ion concentration, defined by the formula $\text{pH} = -\log[\text{H}^+]$.

Buffer

A substance containing both acid and base properties that resists drastic shifts in pH by accepting or donating hydrogen ions.

Ocean Acidification

The lowering of ocean pH caused by dissolved atmospheric $\text{CO}_2$ reacting with seawater to form carbonic acid ($\text{H}_2\text{CO}_3$), depleting carbonate ions required for marine calcification.

Organic Chemistry

The scientific study of carbon-containing compounds.

Hydrocarbons

Organic molecules consisting entirely of carbon and hydrogen atoms.

Isomers

Compounds that have the same molecular formula but different structural arrangements, resulting in distinct chemical and physical properties.

Structural Isomers

Isomers that differ in the covalent arrangements of their constituent atoms.

Cis-Trans Isomers

Isomers that differ in the spatial arrangement of atoms around a rigid carbon-carbon double bond.

Enantiomers

Isomers that are non-superimposable mirror images of each other around a central asymmetric carbon atom.

Functional Groups

Specific molecular substituents attached to a carbon skeleton that consistently affect the molecule's chemical function and properties.

Hydroxyl Group

A polar functional group consisting of a hydrogen atom bonded to an oxygen atom ($-\text{OH}$), forming alcohols and increasing water solubility.

Carbonyl Group

A functional group featuring a carbon atom joined to an oxygen atom by a double bond ($>\text{C=O}$), categorized into aldehydes and ketones.

Carboxyl Group

A functional group consisting of a carbon double-bonded to an oxygen and single-bonded to a hydroxyl group ($-\text{COOH}$), acting as an organic acid.

Amino Group

A functional group composed of a nitrogen atom bonded to two hydrogen atoms ($-\text{NH}_2$), acting as a base by picking up $\text{H}^+$.

Sulfhydryl Group

A functional group consisting of a sulfur atom bonded to a hydrogen atom ($-\text{SH}$), capable of forming covalent disulfide cross-links in proteins.

Phosphate Group

A polar, high-energy functional group consisting of a phosphorus atom bonded to four oxygen atoms ($-\text{PO}_4^{2-}$), imparting a negative charge to the molecule.

Methyl Group

A non-polar, hydrophobic functional group composed of a carbon bonded to three hydrogen atoms ($-\text{CH}_3$), involved in gene expression and epigenetics.

Macromolecules

Large complex polymers built by joining many smaller molecular subunits (monomers) together.

Monomer

A repeating structural subunit that serves as the building block of a polymer.

Dehydration Synthesis

A chemical reaction that covalently links monomers into polymers through the removal of a water molecule.

Hydrolysis

A chemical process that breaks polymers down into individual monomers through the addition of a water molecule.

Carbohydrates

Biomolecules composed of carbon, hydrogen, and oxygen with a general ratio of $\text{CH}_2\text{O}$, serving as energy sources and structural support.

Monosaccharides

The simplest carbohydrate units (single sugars) containing 3 to 7 carbon atoms, existing in linear or ring structures.

Disaccharides

Double sugars formed when two monosaccharides are linked together by a covalent glycosidic linkage via dehydration synthesis.

Glycosidic Linkage

A covalent bond formed between two monosaccharides through a dehydration reaction.

Polysaccharides

Long polymers of monosaccharides joined by glycosidic linkages, used for energy storage or structural frameworks.

Starch

A helical storage polysaccharide in plants composed of $1\text{--}4$ linkages of $\alpha\text{-glucose}$ monomers.

Cellulose

A straight, unbranched structural polysaccharide found in plant cell walls composed of $1\text{--}4$ linkages of $\beta\text{-glucose}$ monomers.

Glycogen

A highly branched energy storage polysaccharide found in animal liver and muscle cells.

Lipids

A diverse group of hydrophobic biomolecules made of carbon, hydrogen, and oxygen with a high carbon-to-oxygen ratio.

Triacylglycerol

A fat molecule constructed from three fatty acid chains joined to a single glycerol molecule by ester linkages.

Saturated Fatty Acid

A fatty acid chain with no double bonds between carbon atoms, containing the maximum possible number of hydrogen atoms.

Unsaturated Fatty Acid

A fatty acid chain containing one or more double bonds ($\text{C=C}$), causing a kink in the hydrocarbon chain that lowers density and melting point.

Phospholipid

An amphipathic lipid consisting of a glycerol attached to two hydrophobic fatty acid tails and a hydrophilic phosphate head group.

Steroids

Lipids characterized by a carbon skeleton composed of four fused rings without fatty acid tails, such as cholesterol and steroid hormones.

Proteins

Functional biomolecules constructed from one or more polypeptide chains made of amino acids linked by peptide bonds.

Amino Acid

The monomer building block of proteins, featuring a central carbon attached to an amino group, a carboxyl group, a hydrogen atom, and a variable R side chain.

Peptide Bond

The covalent bond formed between the carboxyl group of one amino acid and the amino group of another via dehydration synthesis.

Primary Structure

The specific linear sequence of amino acids within a polypeptide chain.

Secondary Structure

Repetitive coiling or folding of the polypeptide backbone ($\alpha\text{-helices}$ and $\beta\text{-pleated sheets}$) held together by hydrogen bonds.

Tertiary Structure

The overall three-dimensional shape of a polypeptide chain resulting from interactions among amino acid R groups.

Quaternary Structure

The overall protein structure formed by the aggregation of two or more individual polypeptide chains.

Denaturation

A process in which a protein loses its native three-dimensional shape and biological function due to heat, extreme pH, or high salt concentrations.

Nucleic Acids

Informational macromolecules composed of nucleotide monomers containing C, H, O, N, and P, serving to store and transmit genetic code.

Nucleotide

The repeating monomer unit of nucleic acids, consisting of a pentose sugar, a nitrogenous base, and a phosphate group.

Pyrimidines

Nitrogenous bases characterized by a single six-membered ring, including cytosine (C), thymine (T), and uracil (U).

Purines

Nitrogenous bases characterized by a six-membered ring fused to a five-membered ring, including adenine (A) and guanine (G).

DNA vs. RNA

DNA is a double-stranded helix containing deoxyribose sugar and thymine; RNA is single-stranded, contains ribose sugar and uracil, and is directly used for protein synthesis.