Review

Passive Transport

Movement of substances across a cell membrane without consuming adenosine triphosphate (ATP), occurring down a concentration gradient.

Simple Diffusion

Unassisted movement of molecules through the phospholipid bilayer from high to low concentration, no ATP or transport protein needed.

Facilitated Diffusion

Movement of substances through a transmembrane protein from high to low concentration; requires a transport protein but not ATP.

Active Transport

Movement of substances from low to high concentration across a cell membrane, requiring ATP and a transport protein.

Secondary Active Transport

Uses energy from an existing ion gradient to move substances against their concentration gradient without using ATP directly.

Osmosis

Specialized passive diffusion of water across a selectively permeable membrane, moving towards a higher solute concentration.

Filtration

Movement of water and small solute molecules across a membrane driven by physical pressure, not requiring ATP.

Phagocytosis

Active transport mechanism where a cell engulfs large solid particles to form a vesicle, requiring ATP.

Pinocytosis

Endocytosis process where a cell takes in extracellular fluid and dissolved substances into small vesicles, consuming ATP.

Hypertonic Solution

A solution with a higher concentration of solutes outside the cell, causing water to exit the cell and leading to shrinkage.

Hypotonic Solution

A solution with a lower concentration of solutes outside the cell, causing water to enter the cell and leading to swelling.

Isotonic Solution

A solution where solute concentrations are equal on both sides of the membrane, resulting in no net water movement.

Solvent

The substance that does the dissolving in a solution, for example, water in a saltwater solution.

Solute

The substance that becomes dissolved in a solution, for example, salt in a saltwater solution.

Organic Compounds

Compounds containing carbon bonded to hydrogen, mainly including carbohydrates, lipids, and proteins.

Inorganic Compounds

Compounds generally lacking a carbon-hydrogen framework, such as water and mineral salts.

Metabolism

The sum total of all chemical reactions occurring within a cell or organism.

Kinetic Energy

The energy of motion that performs work through particle movement.

Potential Energy

Stored energy held for later release.

Ligand

Any molecule that specifically binds to a receptor or target protein to trigger a biological response.

Isotope

Atoms of the same element that have the same number of protons but different numbers of neutrons.

Absorption

The process of taking a substance into a cell, tissue, or bloodstream.

Secretion

The release of a substance produced by a cell or gland.

pH Scale

A measure of the concentration of free hydrogen ions (H⁺) in a solution, indicating acidity or basicity.

Buffer

A substance that helps maintain stable pH levels by resisting rapid changes.

Water

A polar molecule essential for life, serving as an excellent solvent for polar and ionic substances.

Sodium (Na⁺) and Potassium (K⁺)

Ions that play key roles in fluid balance, nerve impulses, muscle contraction, and maintaining membrane potential.

Properties of Gases

Gases lack a fixed shape and volume, moving freely and are highly compressible.

Chemical Bonds

Forces holding atoms together through electron interactions, including ionic, covalent, and hydrogen bonds.

Protein Structure

The four levels of structural organization in proteins: primary, secondary, tertiary, and quaternary.

ATP

Adenosine triphosphate, the main immediate energy-transfer molecule in the cell.

Cell Organelles

Specialized structures within a cell that perform necessary functions for cellular survival.

Transcription

The process of synthesizing RNA from a DNA template within the nucleus.

Translation

The process of using messenger RNA (mRNA) to synthesize a protein at the ribosomes.

Plasma Membrane

The cell's outer boundary that regulates the passage of materials in and out of the cell.

Plasma Membrane Composition

Main components include phospholipids, proteins, cholesterol, and carbohydrates.

Cell Junctions

Connections between adjacent cells that enable communication and adhesion.

Lumen

The open space or cavity inside a tube or hollow organ.

Lacuna

A small space containing a cell, particularly within cartilage or bone tissue.

-blast, -clast, -cyte

Naming conventions indicating cell activity: -blast builds, -clast breaks down, -cyte maintains mature tissue.