A Tour of the Cell: Structure and Function Overview

Cell

The fundamental unit of life.

Organelles

Specialized membrane-bound structures performing distinct functions.

Cytoskeleton

Network of fibers provides structural support to cells.

Microscopy

Technique for visual examination of cells.

Cell Theory

Cells are life's basic units; arise from others.

Electron Microscopy (EM)

Technique using electrons for high-resolution imaging.

Prokaryotic Cells

Cells without membrane-bound organelles.

Plasma Membrane

Cell membrane controls substance entry and exit.

Cytosol

Cytoplasm's fluid substance containing free ribosomes, semifluid.

Ribosomes

synthesize proteins from mRNA, on Rough ER.

Nucleoid

Region in prokaryotes containing concentrated DNA.

Endoplasmic Reticulum (ER)

Membrane network for protein and lipid synthesis, biosynthetic factory.

Rough ER

Ribosomes synthesize proteins for cellular export.

Smooth ER

ER without ribosomes, involved in lipid synthesis.

Nucleus

Organelle containing most eukaryotic cell genes. Averages about 5 µm in diameter.

Mitochondria

produce ATP, powering cellular respiration processes. Typically 1-10 µm in length.

Microtubules

Thick cytoskeletal filaments made of tubulin for transport.

Intermediate Filaments

Fibers and fibrous proteins offer mechanical and structural support within cells, ensuring stability. Cytoskeletal components 8-12 nm in diameter.

Nuclear envelope

Double membrane separating nucleus from cytoplasm.

Nuclear pores

Perforations allowing transport between nucleus and cytoplasm.

Chromosomes

Discrete units of DNA carrying genetic information.

Free ribosomes

Ribosomes synthesizing proteins for cytosol function.

Bound ribosomes

Ribosomes attached to endoplasmic reticulum or nuclear envelope.

Endomembrane System

Network of membranes for protein synthesis and transport.

Golgi Apparatus

Center for manufacturing, sorting, and shipping proteins.

Lysosome

Intracellular organelle for digestion and waste processing.

Vacuoles

Vesicles for storage organelles for nutrients and waste functions.

Chloroplasts

Sites of photosynthesis in plants and algae. Ranges from 3-6 µm.

Eukaryotic cells

Cells that contain internal membrane-bound organelles, including mitochondria.

Cilia

Short extensions for cell movement, differing in motion.

Microfilaments

Actin microfilaments aid cell movement, thinnest fibers.

Cell Wall

rigid support for plants. Ranges from 0.1 µm to several micrometers

Extracellular Matrix (ECM)

Network of glycoproteins outside surrounding animal cells providing support and signaling.

Tight Junctions

Prevent leakage of extracellular fluid between cells.

Desmosomes

Anchoring junctions fastening cells into strong sheets.

Gap Junctions

Cytoplasmic channels allowing communication between cells.

Transport Vesicles

Membrane-bound sacs that transport materials within cells, including proteins and lipids.

Surface area to volume ratio

Large vacuoles, smaller cells, efficient exchange.

Cellular respiration

breaks down glucose for ATP energy, using oxygen and releasing carbon dioxide and water.

ATP

Energy currency of the cell.

Cytoplasm

Interior of prokaryotic and eukaryotic cells.