Unit 2: Cell Structure and Function (copy)

Cell

Life's basic unit of structure and function.

Structure-Function

The principle that the way a cell (or any cell part) is built helps explain what it can do.

Prokaryotic Cells

Cells that are generally smaller and lack membrane-bound organelles; genetic material is found in the nucleoid.

Eukaryotic Cells

Cells that have internal membranes forming membrane-bound organelles, allowing for compartmentalization.

Nucleus

The largest organelle in a eukaryotic cell that stores hereditary information (DNA) organized as chromatin.

Ribosomes

Sites of protein synthesis, made of rRNA and proteins, that are not membrane-bound.

Endoplasmic Reticulum (ER)

A continuous channel extending throughout the cytoplasm that provides mechanical support and helps with protein and lipid transport.

Golgi Apparatus

A cell's packaging and distribution center that modifies, processes, and sorts products received from the ER.

Lysosomes

Organelles that contain digestive enzymes used to break down macromolecules.

Vacuoles

Fluid-filled sacs that store water, food, waste, salts, or pigments; prominent in plant cells for turgor pressure.

Mitochondria

Organelles that convert energy from organic molecules into ATP, with their own DNA and ribosomes.

Chloroplasts

Organelles in plants and algae that perform photosynthesis and contain chlorophyll.

Cytoskeleton

A dynamic network of protein fibers that provide support, movement, and organization within the cell.

Plasma Membrane

A selectively permeable barrier that regulates transport, communication, and maintenance of gradients.

Fluid Mosaic Model

The model describing the plasma membrane as a fluid structure with a mosaic of various proteins embedded in it.

Passive Transport

Movement across membranes that does not require energy, occurring down concentration gradients.

Diffusion

The net movement of particles from higher concentration to lower concentration.

Osmosis

The diffusion of water across a selectively permeable membrane.

Tonicity

The effect a solution has on cell volume via nonpenetrating solutes.

Water Potential

A measure of the potential energy of water, influencing its movement across cell membranes.

Active Transport

The process of moving substances against their concentration gradient, requiring energy.

Endocytosis

The process of bringing material into the cell through vesicle formation.

Exocytosis

The process of exporting material from the cell via vesicles fusing with the plasma membrane.

Endosymbiotic Theory

The theory that mitochondria and chloroplasts originated as prokaryotes that entered a host cell.