Lecture Notes on Basic Chemistry for Biology (Video)

Vocabulary flashcards covering key concepts from the lecture notes on chemical bonds, mixtures, pH, acids/bases, and related topics.

Water (H2O)

Molecule with two hydrogen atoms and one oxygen; a polar covalent molecule capable of forming hydrogen bonds and dissolving many substances.

Molecule

A group of two or more atoms bonded together.

Ion

An atom that has gained or lost electrons, acquiring a net electrical charge.

Cation

Positively charged ion formed when an atom loses electrons.

Anion

Negatively charged ion formed when an atom gains electrons.

Ionic bond

Bond formed by attraction between oppositely charged ions after electron transfer.

Covalent bond

Bond formed when atoms share electrons.

Nonpolar covalent bond

Covalent bond with equal sharing of electrons; no partial charges.

Polar covalent bond

Covalent bond with unequal sharing of electrons, creating partial charges and a dipole.

Hydrogen bond

Weak attraction between a partially positive hydrogen and a highly electronegative atom (often O or N) in another molecule.

Van der Waals forces

Very weak intermolecular attractions; accumulate significance when many are present, especially in nonpolar substances.

Solvent

The dissolving medium in a solution.

Solute

The substance dissolved in the solvent.

Solution

A homogeneous mixture of solute(s) dispersed uniformly in solvent.

Colloid

A heterogeneous mixture with dispersed particles that scatter light (e.g., gelatin, cytoplasm).

Suspension

A heterogeneous mixture with large particles that settle out over time (e.g., blood cells in plasma).

Concentration

Amount of solute dissolved in a solvent; determines how much of the solute is present.

Electronegativity

Tendency of an atom to attract electrons in a bond; leads to polar covalent bonds.

Valence shell

Outermost electron shell; its fullness determines reactivity and bonding behavior.

Inert

Stable; outer electron shell is full, leading to low reactivity.

Reactive

Outer shell is not full, making atoms prone to form bonds.

Atomic number

Number of protons in the nucleus; for neutral atoms, also equals the number of electrons.

Electron shell capacity

Maximum electrons per shell (2 in the first; 8 in the second; 8 in the third for many elements; third shells can hold up to 18 in heavier atoms).

Carbon

Central element in organic chemistry (atomic number 6); can form up to four covalent bonds.

Ionization

Process of forming ions by gaining or losing electrons.

Salt

Ionic compound formed from acid-base reactions; dissociates into ions in water.

Acid

Substance that releases hydrogen ions in water, lowering pH.

Base

Substance that accepts protons or releases hydroxide ions in water, increasing pH.

pH

Measure of hydrogen ion concentration in solution; scale 0-14; neutral is 7; below 7 acidic; above 7 basic; logarithmic.

Buffer

Substance/system that resists changes in pH by neutralizing added acids or bases.

Carbonic acid–bicarbonate buffer

Blood buffer: CO2 + H2O ⇌ H2CO3 ⇌ H+ + HCO3-; helps maintain pH; connects with respiration and kidneys.

Anabolic (synthesis)

Building larger molecules from smaller units; requires energy; often endergonic.

Catabolic (decomposition)

Breaking down complex molecules into simpler ones; releases energy; often exergonic.

Endergonic

Reactions that absorb energy to proceed.

Exergonic

Reactions that release energy.

Redox (oxidation–reduction)

Reactions involving transfer of electrons; oxidation loses electrons, reduction gains electrons.

Equilibrium

State where forward and reverse reactions occur at equal rates, leading to stable concentrations.

Rate of reaction

Speed at which reactants are converted to products; influenced by temperature, concentration, particle size, and catalysts.

Catalyst

Substance (often an enzyme) that increases reaction rate by lowering activation energy.

Inorganic compound

Compound that typically lacks carbon; often small molecules like salts, acids, and bases.

Organic compound

Compounds containing carbon (often with hydrogen and other elements); can be polar or nonpolar and form diverse structures.

Water properties (summary)

High heat capacity, high heat of vaporization, excellent solvent, and surface tension due to hydrogen bonding and polarity.