Unit 2: Cell Structure and Function (copy)

Prokaryotic Cell

A simple, smaller type of cell that lacks membrane-bound organelles; examples include bacteria and archaea.

Eukaryotic Cell

A more complex cell type that contains membrane-bound organelles; examples include fungi, plants, and animals.

Plasma Membrane

The outer envelope of the cell, mainly composed of phospholipids and proteins, that regulates the movement of substances in and out of the cell.

Cytoplasm

The gel-like substance within the cell membrane, containing organelles and cytosol.

Ribosomes

Round structures composed of rRNA and proteins; sites for protein synthesis within the cell.

Endoplasmic Reticulum (ER)

A continuous channel extending into the cytoplasm, responsible for mechanical support and transportation of materials.

Golgi Complex

The organelle that modifies, processes, and sorts proteins for transport within or out of the cell.

Mitochondria

Organelles that convert energy from organic molecules into ATP, the energy currency of the cell.

Lysosomes

Sac-like organelles that carry digestive enzymes to break down old organelles and debris.

Vacuoles

Fluid-filled sacs used for storage of substances like water, food, wastes, and salts.

Peroxisomes

Organelles that detoxify various substances, and break down hydrogen peroxide into harmless byproducts.

Cytoskeleton

A network of protein fibers that give the cell its shape and assist in cellular movement.

Diffusion

The process by which substances move from an area of higher concentration to an area of lower concentration.

Osmosis

The diffusion of water across a selectively permeable membrane.

Active Transport

The movement of substances against their concentration gradient, requiring energy, typically from ATP.

Endocytosis

The process by which a cell engulfs large particles or substances, forming a vacuole or vesicle.

Exocytosis

The process by which a cell ejects waste products or specific secretions by merging a vesicle with the plasma membrane.

Tonicity

A term used to describe the relative concentrations of solute in a solution compared to that of a cell.

Isotonic Solution

A solution where the solute concentration is the same inside and outside the cell.

Hypertonic Solution

A solution that has a higher concentration of solutes compared to the cell, leading to cell shrinkage.

Hypotonic Solution

A solution that has a lower concentration of solutes compared to the cell, leading to cell swelling.

Fluid-Mosaic Model

A model that describes the structure of the plasma membrane as a mosaic of various components that move fluidly.

Facilitated Diffusion

A type of passive transport that requires a protein to help move substances across the plasma membrane.

Aquaporins

Specific channel proteins that facilitate the transport of water across the cell membrane.