flashback quiz

Activation Energy

The energy required to start a chemical reaction.

Active Transport

Movement of molecules against their concentration gradient, requiring energy (ATP).

Bulk Transport

The movement of large molecules or particles into or out of cells (via endocytosis or exocytosis).

Catalyst

A substance that increases the rate of a chemical reaction without being consumed.

Cohesion

The attraction between water molecules.

Contractile Vacuole

An organelle in some protists that expels excess water to maintain osmotic balance.

Cytolysis

The bursting of an animal cell when placed in a hypotonic solution.

Diffusion

The movement of molecules from high to low concentration until equilibrium is reached.

Endocytosis

The process by which cells engulf large molecules or particles by wrapping the cell membrane around them.

Enzyme

A protein that speeds up chemical reactions by lowering activation energy.

Exocytosis

The process by which cells expel large molecules by fusing vesicles with the cell membrane.

Facilitated Diffusion

Movement of molecules across a membrane via a protein channel, from high to low concentration (no energy required).

Hypertonic

A solution with higher solute concentration than inside the cell (causes cells to shrink).

Hypotonic

A solution with lower solute concentration than inside the cell (causes cells to swell).

Isotonic

A solution with the same solute concentration as inside the cell (no net movement of water).

Nucleotides

Building blocks of nucleic acids (DNA and RNA), consisting of a sugar, phosphate group, and nitrogenous base.

Osmosis

The movement of water through a semipermeable membrane from low to high solute concentration.

Plasmolysis

The shrinkage of a plant cell membrane from the cell wall when placed in a hypertonic solution.

Polypeptides

Chains of amino acids that fold into proteins.

Polysaccharides

Large carbohydrates made of many monosaccharides (e.g., starch, cellulose).

Substrate

The molecule upon which an enzyme acts in a chemical reaction.

Surface Tension

The force that causes the surface of a liquid to contract and resist external force, due to cohesion.

Transpiration

The process by which plants release water vapor into the air through stomata.

Triglycerides

A type of lipid made of glycerol and three fatty acids; main form of fat storage.

Turgor Pressure

The pressure exerted by the cell membrane against the cell wall due to water intake in plant cells.