Biochemistry and the Chemical Basis of Life

Vocabulary flashcards focusing on biochemistry, atomic structure, chemical bonds, water properties, and pH balance based on lecture notes.

Biochemistry

The study of the chemical basis of life, focusing on the atomic and molecular components that compose cells and organisms.

Matter

Anything that takes up space and has mass; it can exist as a solid, liquid, or gas and is composed of elements.

Elements

Substances that cannot be broken down into anything smaller, of which $92$ occur naturally in the world.

Main Biological Elements

The four main elements—carbon, hydrogen, oxygen, and nitrogen—that make up $96\%$ of the human body.

Atom

The particulate unit that makes up elements, composed of neutrons, protons, and electrons.

Atomic Theory

The theory stating that elements consist of atoms, which are composed of protons, neutrons, and electrons.

Neutrons

Subatomic particles that carry a neutral charge and are located within the nucleus of an atom.

Protons

Subatomic particles that carry a positive charge and are located within the nucleus of an atom.

Electrons

Subatomic particles carrying a negative charge that orbit outside the nucleus and allow for bonding between elements.

Mass Number

The sum of the protons and neutrons inside the nucleus of an element.

Atomic Number

An element's number of protons, which also equals the number of electrons in a neutral atom.

Periods

The horizontal rows on the periodic table where elements are arranged by atomic number.

Groups

The vertical columns on the periodic table where elements are arranged by atomic number.

Isotopes

Variations of atoms of the same element that contain a different number of neutrons.

Octet Rule

The rule stating that an atom with more than two shells is most stable when its outermost shell contains eight electrons.

Valence Shell

The outermost electron shell of an atom.

Molecule

A structure formed when an atom typically bonds to itself, such as an $O_2$ molecule.

Compound

A structure formed when atoms of different elements bond together, such as $H_2O$ or $C_6H_{12}O_6$.

Ionic Bonding

Bonding that occurs when two atoms are held together by opposite electrical charges created when one element transfers an electron to another.

Covalent Bonding

A strong form of chemical bonding where two different elements share electrons in their valence shells.

Double Covalent Bond

A strong covalent interaction where two atoms share four electrons (two pairs) between their valence shells.

Reactants

The starting substances listed before the yielding arrow in a chemical reaction equation.

Products

The substances produced or yielded in a chemical reaction, listed after the arrow in a chemical equation.

Polar Covalent Bond

A covalent bond formed by the unequal sharing of electrons, resulting in slight positive and negative charges across the molecule.

Hydrogen Bonds

The weakest bonds in existence, occurring between individual water molecules or influencing protein shapes.

Hydrophilic

Describing a 'water-loving' molecule that readily dissolves or dissociates in water.

Hydrophobic

Describing a 'water-fearing' molecule that does not dissolve or react with water, such as oil.

Cohesion

The ability of water molecules to cling to other water molecules via hydrogen bonding.

Adhesion

The ability of water molecules to cling to other non-water substances.

Surface Tension

The property of water where surface molecules cling more tightly to each other than to the air above due to hydrogen bonding.

Heat Capacity

The ability of water to absorb heat without changing temperature quickly, protected by its hydrogen bonds.

Heat of Vaporization

The high amount of energy required to break hydrogen bonds in water to allow it to evaporate.

pH

A measurement of the potential of attracting hydrogen ions in a substance, spanning a scale from $0$ to $14$.

Acidic Solution

A solution with a pH less than $7$ (ranging from $0$ to $6.9$) containing a higher concentration of hydrogen ions ($H^+$).

Basic Solution

A solution with a pH greater than $7$ (ranging from $7.1$ to $14$) containing a higher concentration of hydroxide ions ($OH^-$).

Buffer

A chemical system that can resist pH changes and maintain a stable pH close to $7$.

Acidosis

A dangerous physiological state that occurs when blood pH drops below its normal range of $7.35$ to $7.45$ due to an accumulation of hydrogen ions.