AP Bio | Unit 2 Review

Cell Theory

The concept that all living organisms are composed of cells, which are the basic unit of life, and that all cells arise from pre-existing cells.

Prokaryotic Cells

Cells that lack a nucleus and membrane-bound organelles; they include bacteria and archaea.

Eukaryotic Cells

Cells that contain a nucleus and other membrane-bound organelles.

Amphipathic Molecule

A molecule that has both hydrophobic (water-repelling) and hydrophilic (water-attracting) regions, such as phospholipids in the cell membrane.

Fluid Mosaic Model

A description of the cell membrane structure, depicting it as a mosaic of various components including phospholipids, cholesterol, and proteins that move freely within the lipid bilayer.

Diffusion

The passive movement of solute molecules from an area of higher concentration to an area of lower concentration.

Osmosis

The diffusion of water across a selectively permeable membrane.

Tonicity

The ability of a surrounding solution to cause a cell to gain or lose water; includes isotonic, hypertonic, and hypotonic solutions.

Endocytosis

The process in which a cell engulfs materials into a membrane-bound vesicle, including phagocytosis, pinocytosis, and receptor-mediated endocytosis.

Exocytosis

The process of vesicles fusing with the plasma membrane to release their contents outside the cell.

Signal Transduction Pathway

A series of molecular events and reactions that lead to a cellular response after a stimulus is detected by a cell.

Apoptosis

The process of programmed cell death that occurs in multicellular organisms.

Nucleoid

The region in a prokaryotic cell where the genetic material (DNA) is located, not enclosed by a membrane.

Phagocytosis

A form of endocytosis in which a cell engulfs large particles or microorganisms.

Plasmodesmata

Channels between plant cells that allow for transport and communication.

Plasma Membrane

A biological membrane that separates and protects the interior of a cell from its external environment.

Chloroplast

An organelle found in plant cells and algae that conducts photosynthesis, converting sunlight into energy.

Mitochondria

Organelles known as the powerhouse of the cell, responsible for producing ATP through cellular respiration.

Cytoskeleton

A network of fibers that helps the cell maintain its shape and provides support; includes microtubules, microfilaments, and intermediate filaments.

Glycoprotein

A protein that has carbohydrate chains attached, playing critical roles in cell recognition and signaling.

Homeostasis

The process by which biological systems maintain stability while adjusting to conditions that are optimal for survival.

Quorum Sensing

The regulation of gene expression in response to fluctuations in cell-population density.

Aquaporin

A channel protein in the plasma membrane that specifically facilitates the transport of water molecules.