biology

Cell Wall

Rigid cell covering made of various molecules that protects the cell, provides structural support, and gives shape to the cell.

Central Vacuole

Large plant cell organelle that regulates storage, holds water, and plays a role in cell growth and macromolecule degradation.

Centrosome

Region in animal cells made of two centrioles.

Chlorophyll

Green pigment that captures light energy to drive the light reactions of photosynthesis.

Chloroplast

Plant cell organelle that carries out photosynthesis.

Chromatin

Protein-DNA complex that serves as the building material of chromosomes.

Chromosome

Structure within the nucleus made of chromatin containing DNA, the hereditary material.

Cilium (plural = cilia)

Short, hair-like structure extending from the plasma membrane used to move the cell or substances along its outer surface.

Cytoplasm

Entire region between the plasma membrane and nuclear envelope, consisting of cytosol, cytoskeleton, and organelles.

Cytoskeleton

Network of protein fibers that maintain cell shape, secure organelles, and enable movement.

Cytosol

Gel-like material of the cytoplasm in which cell structures are suspended.

Desmosome

Linkage between adjacent epithelial cells formed when cadherins attach to intermediate filaments.

Electron Microscope

An instrument that magnifies an object using a beam of electrons passed and bent through a lens system.

Endomembrane System

Group of organelles and membranes in eukaryotic cells that modify, package, and transport lipids and proteins.

Endoplasmic Reticulum (ER)

Series of interconnected membranous structures that modify proteins and synthesize lipids.

Eukaryotic Cell

Cell that has a membrane-bound nucleus and other membrane-bound compartments.

Extracellular Matrix

Material secreted from animal cells providing mechanical protection and anchoring for tissue cells.

Flagellum (plural = flagella)

Long, hair-like structure extending from the plasma membrane used to move the cell.

Gap Junction

Channel between adjacent animal cells allowing ions and nutrients to pass for communication.

Golgi Apparatus

Eukaryotic organelle of stacked membranes that sorts, tags, and packages lipids and proteins.

Intermediate Filament

Cytoskeletal component composed of fibrous protein that bears tension and supports junctions.

Light Microscope

An instrument that magnifies an object using visible light passed and bent through a lens system.

Lysosome

Animal cell organelle that acts as the digestive component, breaking down macromolecules and worn-out organelles.

Microfilament

Narrowest element of the cytoskeleton providing rigidity, shape, and enabling cellular movements.

Microscope

An instrument that magnifies an object.

Microtubule

Widest element of the cytoskeleton that resists compression, provides tracks for vesicles, and forms spindle fibers.

Mitochondria

Organelles responsible for cellular respiration and ATP production.

Nuclear Envelope

Double-membrane structure constituting the outermost portion of the nucleus.

Nucleoid

Central part of a prokaryotic cell where the chromosome is found.

Nucleolus

Darkly staining body within the nucleus responsible for assembling ribosome subunits.

Nucleoplasm

Semi-solid fluid inside the nucleus containing chromatin and the nucleolus.

Nucleus

Cell organelle that houses DNA and directs the synthesis of ribosomes and proteins.

Organelle

Compartment or sac within a cell.

Peroxisome

Small, round organelle containing hydrogen peroxide that oxidizes fatty/amino acids and detoxifies poisons.

Plasma Membrane

Phospholipid bilayer with embedded proteins that separates internal cell contents from the environment.

Plasmodesma (plural = plasmodesmata)

Channel passing between cell walls of adjacent plant cells connecting their cytoplasm.

Prokaryote

Unicellular organism that lacks a nucleus or membrane-bound organelles.

Ribosome

Cellular structure that carries out protein synthesis.

Rough Endoplasmic Reticulum (RER)

Region of ER studded with ribosomes engaged in protein modification and phospholipid synthesis.

Smooth Endoplasmic Reticulum (SER)

Region of ER lacking ribosomes that synthesizes lipids, metabolizes carbohydrates, and detoxifies chemicals.

Tight Junction

Firm seal between adjacent animal cells created by protein adherence.

Unified Cell Theory

Concept stating all organisms are made of cells, the cell is the basic unit of life, and new cells arise from existing cells.

Vacuole

Membrane-bound sac larger than a vesicle that functions in cellular storage and transport.

Vesicle

Small, membrane-bound sac that functions in cellular storage and transport.