Chemistry & Cell Biology Basics

Vocabulary flashcards covering atomic structure, chemical bonding, molecular polarity, intermolecular forces, and basic cell biology organelles.

Subatomic Particles

Protons, neutrons, and electrons that make up an atom.

Atomic Number

Number of protons in an atom; also equals the number of electrons in a neutral atom.

Mass Number

Sum of protons and neutrons in an atom’s nucleus.

Isotope

Atoms of the same element with different numbers of neutrons and therefore different mass numbers.

Atomic Mass Unit (amu)

Standard unit of mass for subatomic particles; 1 amu ≈ 1.66 × 10⁻²⁴ g.

Electronegativity (EN)

Ability of an atom to attract shared electrons in a bond; increases up and to the right on the periodic table.

Ionic Bond

Chemical bond formed by transfer of electrons between a metal and a non-metal (ΔEN > 2.0).

Results in ions being formed

Covalent Bond

Chemical bond formed by sharing electrons between non-metal atoms (ΔEN < 2.0).

Non-Polar Covalent Bond

Bond with equal electron sharing; ΔEN < 0.5 (e.g., C–H).

Polar Covalent Bond

Bond with unequal electron sharing; 0.5 < ΔEN < 2.0 (e.g., H–Cl).

Molecular Polarity

Condition where a molecule has an uneven distribution of charge due to polar bonds and asymmetrical shape.

Symmetrical Shapes

Linear, trigonal planar, tetrahedral, trigonal bipyramidal, octahedral geometries; often yield non-polar molecules if bonds are identical.

Non-Symmetrical Shapes

Bent and trigonal pyramidal geometries; often result in polar molecules.

VSEPR Theory

Model that predicts molecular shape based on repulsion between electron domains around a central atom.

Crystalline Solid

Highly ordered solid structure characteristic of ionic compounds at room temperature.

Conductivity of Ionic Compounds

Ionic substances conduct electricity when molten or dissolved in water due to mobile ions.

Melting Point: Ionic vs Covalent

Ionic compounds have very high melting points (> 600 °C); covalent compounds generally melt at lower temperatures.

Like Dissolves Like

Polar solvents dissolve polar or ionic solutes; non-polar solvents dissolve non-polar solutes.

Diatomic Molecule

Molecule composed of two identical atoms (H₂, N₂, O₂, F₂, Cl₂, Br₂, I₂).

Intramolecular Forces

Forces (ionic or covalent bonds) holding atoms together within a molecule or compound.

Intermolecular Forces

Attractive forces between separate molecules: hydrogen bonding > dipole-dipole > London dispersion.

Hydrogen Bonding

Strong attraction between H bonded to N, O, or F and a lone pair on another N, O, or F atom.

Dipole-Dipole Forces

Attractions between permanent partial charges of polar molecules.

London Dispersion Forces

Temporary dipoles (positive and negative ends) arising from constant random electron movement; present in all molecules but are strongest in non-polar ones.

Animal Cell

Eukaryotic cells containing membrane-bound organelles and lacking a cell wall.

Nucleus

Houses chromosomes and controls cellular activities. Also contain nucleolus

Nucleolus

Produces ribosomal subunits used in forming proteins

Cytoplasm

 a gel-like fluid containing nutrients, minerals, and water; bathes the cell and holds all organelles in place

Centriole

Involved in cellular division; pulls apart chromosomes during anaphase

Endoplasmic Reticulum

Transports materials within the cell.

Golgi Apparatus

Packages proteins so they survive out the cell

Lysosome

break down chemicals and transport unwanted materials out of the cell

Mitochondria

Generates energy for the cell (ATP); the powerhouse of the cell.

Ribosome

Site of protein synthesis

Vacuole

Membrane-bound sac for storage of water and minerals; very large in plant cells.

Plasma Membrane

Regulates the passage of substances into and out of the cell.

Flagella

Long whip-like structures that propel certain animal cells (e.g., sperm).

Structure that enables motility

Cilia

Short hair-like projections that aid movement or fluid flow (e.g., in tracheal cells).

Structure that enables motility

Plant Cell

Eukaryotic cell type that contains chloroplasts and a cell wall.

Chloroplast

Organelle containing green chlorophyll where photosynthesis occurs. (Only in plant cells)

Cell Wall

Rigid layer outside the plasma membrane in plant cells providing strength and structure.