Unit 1.2 Introduction to Cell Biochemistry Flashcards

Vocabulary flashcards for cell biochemistry, covering matter, atomic structure, bonding types, electronegativity, water interaction, and chemical reactions.

Matter

Anything that has mass and occupies space, existing in four states: solid, liquid, gas, or plasma.

Element

A substance that cannot be broken down into substances with different properties, composed of one type of atom.

CHNOPS

An acronym for the six elements (Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur) that make up $95\%$ of the body weight of organisms.

Human Body Element Composition

The breakdown of major elements by percentage of human body weight: Oxygen ($65\%$), Carbon ($18\%$), Hydrogen ($10\%$), Nitrogen ($3\%$), and others.

Atom

The smallest part of an element that displays the properties of that element.

Proton

A positively charged subatomic particle located in the central nucleus of an atom.

Neutron

A subatomic particle with no charge located in the nucleus, which is slightly heavier than a proton.

Electron

A negatively charged subatomic particle with very low, negligible mass that orbits the nucleus in electron shells.

Valence Shell

The outermost electron shell of an atom that determines many of its chemical properties.

Valence Electrons

The electrons located in the outermost shell of an atom.

Octet Rule

The principle stating that an atom's outermost shell is most stable when it contains eight electrons, or two electrons if it has only one shell.

Molecule

A discrete, electrically neutral group of two or more atoms held together primarily by covalent bonds.

Compound

A pure substance composed of atoms of two or more different elements held together by chemical bonds in a fixed characteristic proportion.

Chemical Bond Strength Hierarchy

The ranking of chemical bond strength in biology from strongest to weakest: covalent bonds > ionic bonds > hydrogen bonds > van der Waals interactions.

Nonpolar Covalent Bond

A covalent bond formed when two atoms share electrons equally due to very similar electronegativity values (difference less than 0.4 - 0.5).

Polar Covalent Bond

A covalent bond formed when two atoms share electrons unequally due to a moderate difference in electronegativity (0.5 - 1.7), creating partial charges.

Anion

A negatively charged atom or molecule containing more electrons than protons, such as $Cl^-$ or $O^{2-}$.

Cation

A positively charged atom or molecule containing fewer electrons than protons, such as $Na^+$ or $Mg^{2+}$.

Electronegativity

The ability of an atom to attract electrons toward itself in a chemical bond.

Hydrogen Bond

A weak attraction between a slightly positive hydrogen atom ($\delta^+$) and a slightly negative atom ($\delta^-$).

Hydrophilic Molecules

Molecules that interact with water through partial charges or ionic charges and are generally soluble in water.

Hydrophobic Molecules

Nonpolar molecules that contain mostly or all nonpolar bonds, lack partial charges, and do not dissolve in water.

Functional Groups

Clusters of specific atoms bonded to a carbon skeleton that possess characteristic structures and functions.

Dehydration Reaction

A chemical reaction in which subunits are joined together by forming a covalent bond, producing a water molecule in the process.

Hydrolysis Reaction

A chemical reaction in which a water molecule is added to break a covalent bond between subunits.