Bio-Chemistry Basics Flashcards

Vocabulary flashcards covering the fundamental concepts of general chemistry and biological macromolecules presented in Chapter 2.

Element

A substance that cannot be broken down into simpler substances by chemical means and is composed of only one type of atom.

Proton

A positively charged subatomic particle located in the atomic nucleus, with a mass of approximately $1\,\text{Da}$.

Neutron

A subatomic particle with no electrical charge, located within the atomic nucleus.

Electron

A negatively charged subatomic particle with negligible mass that moves in orbitals around the nucleus.

Atomic Number

The number of protons contained in the nucleus of an atom, which uniquely identifies a chemical element.

Atomic Mass

The total mass of an atom, calculated as the sum of the number of protons and neutrons in its nucleus.

Isotope

Atoms of the same element that have the same number of protons but a different number of neutrons.

Radioactive Isotope

An unstable isotope whose nucleus decays spontaneously, releasing subatomic particles and energy.

Orbital

A region of space around the nucleus where an electron is most likely to be found.

Valence Electrons

The electrons occupying the outermost energy level or shell of an atom, which determine its chemical reactivity and bonding capacity.

Group (Periodic Table)

A vertical column on the periodic table containing elements that share the same number of valence electrons in their outermost shell.

Covalent Bond

A type of chemical bond formed when two atoms share one or more pairs of valence electrons to fill their outer energy levels.

Electronegativity

A measure of an atom's attraction for shared electrons in a chemical bond.

Polar Covalent Bond

A covalent bond in which shared electrons are pulled closer to the more electronegative atom, giving it a partial negative charge and the other atom a partial positive charge.

Nonpolar Covalent Bond

A covalent bond in which electrons are shared equally between two atoms of similar electronegativity.

Ionic Bond

A chemical bond resulting from the attraction between oppositely charged ions formed when one atom transfers electrons to another.

Cation

A positively charged ion formed when an atom loses one or more electrons.

Anion

A negatively charged ion formed when an atom gains one or more electrons.

Thermal Energy

Kinetic energy associated with the random movement of atoms or molecules, which is dependent on the volume of matter.

Kinetic Energy

The energy possessed by an object due to its motion.

Specific Heat

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

Heat of Vaporization

The quantity of heat energy liquid water must absorb for $1\,\text{g}$ of it to be converted into a gas.

Evaporative Cooling

The process in which the surface of a liquid cools down as the water molecules with the highest kinetic energy escape into the gas phase.

pH Scale

A logarithmic measurement scale of hydrogen ion concentration in an aqueous solution, calculated as $\text{pH} = -\log[H^+]$.

Buffer

A solution typically composed of a weak acid and its corresponding base that minimizes changes in $[H^+]$ and $[OH^-]$ by accepting or donating protons.

Organic Molecules

Carbon-containing chemical compounds that serve as the fundamental structural components of life.

Isomers

Molecules that share the same chemical formula but have different structural arrangements of their atoms.

Enantiomers

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

Functional Groups

Specific configurations of atoms attached to carbon skeletons that directly participate in chemical reactions and impart distinct properties.

Hydroxyl Group

A polar functional group ($-OH$) that forms hydrogen bonds with water, aiding in the dissolution of organic compounds such as alcohols.

Carbonyl Group

A functional group consisting of a carbon atom double-bonded to an oxygen atom ($C=O$), found in aldehydes and ketones.

Carboxyl Group

An acidic functional group ($-COOH$) consisting of a carbon double-bonded to an oxygen atom and single-bonded to a hydroxyl group.

Amino Group

A basic functional group ($-NH_2$) that can accept an $H^+$ ion in solution to become positively charged ($-NH_3^+$).

Sulfhydryl Group

A functional group ($-SH$) present in thiols, such as the amino acid cysteine, which helps stabilize protein structures through cross-linking.

Phosphate Group

An acidic, negatively charged functional group ($-PO_4^{3-}$) essential for nucleic acids and cellular energy transfer molecules like ATP.

Methyl Group

A nonpolar functional group ($-CH_3$) that can modify DNA to affect gene expression.

Monomer

A repeating simple molecular subunit that serves as the building block for polymers.

Polymer

A long chain molecule composed of multiple covalently bonded monomers.

Dehydration Reaction

A chemical reaction that links monomers together into polymers by removing a molecule of water ($H_2O$).

Hydrolysis

A chemical reaction that breaks covalent bonds in polymers to yield individual monomers by adding a water molecule ($H_2O$).

Peptide Bond

The covalent bond formed between two amino acids through a dehydration reaction.

Nucleotide

The monomer building block of nucleic acids, consisting of a 5-carbon sugar, a phosphate group, and a nitrogenous base.

Pyrimidines

Single-ring nitrogenous bases found in nucleic acids, including cytosine (C), thymine (T), and uracil (U).

Purines

Double-ring nitrogenous bases found in nucleic acids, including adenine (A) and guanine (G).

Phosphodiester Bond

A covalent bond linking two nucleotides, formed between the phosphate group of one nucleotide and the $3'$ hydroxyl group of the next sugar.

Glycosidic Linkage

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

Lipids

A group of hydrophobic biomolecules including fats, phospholipids, and steroids that do not form traditional polymers.

Triacylglycerol

A lipid ester formed by linking three fatty acid hydrocarbon chains to a single glycerol molecule; also called a triglyceride.

Van der Waals Forces

Weak electrostatic attractions between nonpolar molecules caused by temporary, fluctuating regional charges in electron clouds.

Saturated Fatty Acid

A fatty acid chain with no carbon-carbon double bonds, allowing maximum hydrogen binding and tight packing, resulting in a solid state at room temperature.

Unsaturated Fatty Acid

A fatty acid chain containing one or more carbon-carbon double bonds that create bends, preventing tight packing and causing it to remain liquid at room temperature.

Trans Fat

An unsaturated fat produced synthetically by hydrogenating oils, converting cis-carbon double bonds into a straight trans-configuration.