Cell Functions


Cell Wall

Plant, Fungi, & Bacteria, but not animal cells

  • Outer layer
  • Rigid & strong
  • Made of cellulose

  • Support (grow tall)
  • Protection
  • allows H2O, O2, CO2 to diffuse in & out of cell
Cell Membrane

All cells

  • Plant – inside cell wall
  • Animal – outer layer; cholesterol
  • Double layer of phospholipids with proteins
  • Selectively permeable
  • Support
  • Protection
  • Controls movement of materials in/out of cell
  • Barrier between cell and its environment
  • Maintains homeostasis


All cells except prokaryotes

  • Large, oval
  • May contain 1 or more nucleoli
  • Holds DNA 
  • Controls cell activities
  • Contains the hereditary material of the cell
Nuclear membrane

All cells except prokaryotes

  • Surrounds nucleus
  • Double membrane
  • Selectively permeable
  • Controls movement of materials in/out of nucleus


All cells

  • Clear, thick, jellylike material (cytosol)
  • Organelles found inside cell membrane
  • Contains the cytoskeleton fibers
  • Supports and protects cell organelles
reticulum (ER)

All cells except prokaryotes

  • Network of tubes or membranes
  • Smooth w/o ribosomes
  • Rough with embedded ribosomes
  • Connects to nuclear envelope & cell membrane
  • Carries materials through cell
  • Aids in making proteins

All cells

  • Small bodies free or attached to ER
  • Made of rRNA & protein
  • Synthesizes proteins

All cells except prokaryotes

  • Peanut shaped 
  • Double membrane
  • Outer membrane smooth
  • Inner membrane folded into cristae
  • Breaks down sugar (glucose) molecules to release energy
  • Site of aerobic cellular respiration

    Plant cells have a single, large vacuole

Animal cells have small vacuoles

  • Fluid-filled sacs
  • Largest organelle in plant cells
  • Store food, water, metabolic & toxic wastes
  • Store large amounts of food or sugars in plants

Plant – uncommon
Animal – common

  • Small and round with a single membrane
  • Breaks down larger food molecules into smaller molecules
  • Digests old cell parts

Plants and algae

  • Green, oval  containing chlorophyll (green pigment)
  • Double membrane with inner membrane modified into sacs called thylakoids
  • Stacks of thylakoids called grana & interconnected
  • Gel like innermost substance called stroma
  • Uses energy from sun to make food (glucose) for the plant
  • Process called photosynthesis
  • Release oxygen

All cells except prokaryotes

  • Found inside the cell’s nucleus
  • May have more than one
  • Disappear during cell division
  • Make ribosomes

Golgi Apparatus
Golgi Apparatus1

All cells except prokaryotes

  • Stacks of flattened sacs
  • Have a cis & trans face
  • Modify proteins made by the cells
  • Package & export proteins

Animal cells, Protozoans

  • Have a 9-2 arrangement of microtubules
  • Short, but numerous


  • Movement



Bacterial cells & Protozoans

  • Have a 9-2 arrangement of microtubules
  • Long, but few in number
  • Movement

Animal cells

  • Paired structures near the nucleus
  • Made of a cylinder of microtubule pairs
  • Separate  chromosome pairs during mitosis

All cells

  • Made of microtubules 7 microfilaments
  • Strengthen cell & maintains the shape
  • Moves organelles within the cell