Biology - Key Terms (Cell Biology & Biochemistry)

30 vocabulary flashcards covering basic biology topics from atoms to cellular energy.

Atom

The smallest unit of matter that retains the properties of an element.

Proton

Positively charged subatomic particle located in the nucleus.

Neutron

Electrically neutral subatomic particle in the nucleus.

Electron

Negatively charged subatomic particle orbiting the nucleus.

Covalent bond

Chemical bond formed by sharing electrons between atoms.

Ionic bond

Bond formed by electrical attraction between oppositely charged ions after electrons are transferred.

Hydrogen bond

Weak attraction between a hydrogen atom and another electronegative atom; important in water and DNA.

Polarity

Unequal sharing of electrons creating partial positive and negative regions within a molecule.

pH scale

Logarithmic scale measuring acidity/basicity of solutions; 0-14, 7 neutral.

Macromolecule

A large molecule built from smaller subunits; includes carbohydrates, lipids, proteins, nucleic acids.

Carbohydrates

Biomolecules of sugars and starches; provide quick energy and structural support in cells.

Lipids

Fats and oils; store long-term energy and form membranes; include phospholipids.

Proteins

Macromolecules composed of amino acids; perform structural, enzymatic, transport, and signaling roles.

Nucleic acids

DNA and RNA; store and transmit genetic information.

DNA

Deoxyribonucleic acid; stores genetic information; typically double-stranded; bases A-T and C-G pair.

RNA

Ribonucleic acid; carries genetic information for protein synthesis; bases A-U, C-G.

Prokaryote

Simple cell type lacking a nucleus; bacteria.

Eukaryote

Complex cell type with a nucleus; includes plants and animals.

Nucleus

Membrane-bound organelle that stores DNA in eukaryotic cells.

Water

Polar solvent with cohesion and adhesion; high heat capacity; universal solvent.

Polar molecule

Molecule with partial charges due to uneven electron distribution; can form hydrogen bonds.

Cohesion

Attraction between like molecules (water molecules sticking together).

Adhesion

Attraction between unlike substances (water sticking to surfaces).

Specific heat

Amount of heat required to raise a substance’s temperature; water has a high specific heat.

Glucose

A simple sugar used for quick energy by cells.

Starch

Plant storage polysaccharide made of glucose units.

Cellulose

Structural polysaccharide in plant cell walls; humans cannot digest.

Chloroplasts

Plant cell organelles where photosynthesis occurs; contain chlorophyll.

Mitochondria

Organelle where cellular respiration occurs; produce ATP.

ATP

Adenosine triphosphate; the energy currency of the cell, produced in mitochondria.