The Cell Overview


List the scientists who contributed to our knowledge of the cell

List the 3 components of the cell theory

Compare prokaryote to eukaryote cells

Label a plant and animal cell

Know the functions of all cell organelles


Early Contributions


Robert Hooke - The first person to see cells, he was looking at cork and noted that he saw "a great many boxes. (1665)

Anton van Leeuwenhock - Observed living cells in pond water, which he called "animalcules" (1673)

Theodore Schwann - zoologist who observed that the tissues of animals had cells (1839)

Mattias Schleiden - botonist, observed that the tissues of plants contained cells (1845)

Rudolf Virchow - also reported that every living thing is made of up vital units, known as cells. He also predicted that cells come from other cells. (1850 )

The Cell Theory

1. Every living organism is made of one or more cellss.
2. The cell is the basic unit of structure and function.
3. All cells arise from pre-existing cells.

*Why is the Cell Theory called a Theory and not a Fact?


Cell Features

Ribosomes - make protein for use by the organism
Cytoplasm - jelly-like goo on the inside of the cell
DNA - genetic material
Cytoskeleton - the internal framework of the cell
Cell membrane - outer boundary of the cell, some stuff can cross the cell membrane.

Types of Cells


Prokaryotic Cells

Prokaryotes are very simple cells, probably first to inhabit the earth.
Prokaryotic cells do not contain a membrane bound nucleus.
Bacteria are prokaryotes.
DNA of bacteria is circular.

The word "prokaryote" means "before the nucleus"

Other features found in some bacteria:

Flagella - used for movement
Pilus - small hairlike structures used for attaching to other cells
Capsule - tough outer layer that protects bacteria, often associated with harmful bacteria


Eukaryotic Cells

Eukaryotic cells are more advanced cells. These cells are found in plants, animals, and protists (small unicellular "animalcules").

The eukaryotic cell is composed of 4 main parts:

cell membrane - outer boundary of the cell

cytoplasm - jelly-like fluid interior of the cell

nucleus - the "control center" of the cell, contains the cell's DNA (chromosomes)

organelles - "little organs" that carry out cell functions


Cell Structures

The Nucleusnucleus

  • Usually found at center of cell
  • Has a nuclear membrane ;nuclear pores
  •  Contains cell's DNA in one of 2 forms
    • chromatin- DNA bound to protein (non-dividing cell)
    • chromosomes- condesed structures seen in dividing cell
  •  Also contains an organelle called nucleolus - which makes the cell’s ribosomes





Energy center or "powerhouse" of the cell. Turns food into useable energy (ATP)

Ribosome - make protein, located on the rough endoplasmic reticulum and throughout the cytoplasm

golgi bodyGolgi Apparatus - processing, packages and secretes proteins; proteins are transported in vesicles


lysosomeLysosome - contains digestive enzymes that can break things down, also called a "suicide sac" because the rupturing of the lysosome will cause the cell to destroy itself

Endoplasmic Reticulum - Transport, "intracellular highway". Ribosomes are positioned along the rough ER, protein made by the ribosomes enter the ER for transport.

Smooth ER - no ribosomes
Rough ER - contains ribosomes

endoplasmic reticulum

Cytoskeleton - helps maintain the cells shape; supports the cell and aids in cell movement\

microtubules / microfilaments / centrioles

microtubules are used to build cilia and flagella

Vacuole - storage area for water and other substances, plant cells usually have a large central vacuole

Protein Production

The cell is like a factory. Its product is protein which goes to body to serve different functions.

  1. DNA has instructions to build; protein
  2. These instructions are sent to ribosomes
  3. The ribosomes build protein and send it through ER
  4. The proteins are delivered to& golgi where they are completed and tagged for export outside the cell

chloroplastPlant Cell

Has all the components of animal cells with some additional structures.

Chloroplast - Uses sunlight to create food, photosynthesis (only found in plant cells), contains green pigment chlorophyll

Cell Wall - outside the cell membrane of plants and some bacteria, the cell wall serves as support

Central vacuole - large water container, helps maintain a turgor (stiffness) in the plant

Animal Cell versus Plant Cell

plant cell



  • The Mitochondria and Chloroplasts have their own DNA
  • ENDOSYMBIOSIS THEORY - eukaryotic cells evolved from the engulfing of bacteria cells, thus creating additional cell parts


  • Function: to regulate what comes into the cell and what goes out
  • Composed of a double layer of phospholipids and proteins



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



Match the words in the first column to the best available answer in the second column. When you are finished, sketch a picture of a cell on the back of your puzzle and label seven of the organelles listed below.


_____ cell theory 1) cell component that carries on a specific job for the cell
_____ Robert Hooke 2) packages materials such as proteins made by the cell
_____ cell 3) make up the membrane of a cell
_____ organelles 4) control center of the cell where DNA is found
_____ prokaryote 5) where proteins are made in all cells
_____ eukaryote 6) states all living things are made of cells
_____ phospholipids 7) cells with a nucleus and membrane-bound organelles
_____ mitochondria 8) structure around the outside of the cell membrane in plants for support and protection
_____ ribosome 9) made of microfilaments and microtubules in the cytoplasm for supportnucleolus
_____ endoplasmic reticulum 10) smallest part of an organism that can carry on all life processes
_____ golgi 11) powerhouses of a cell where ATP (energy) is generated
_____ lysosome 12) store enzymes and waste products in a cell
_____ cilia 13) digests materials within the cell
_____ nucleus 14) short hairlike structures around the outside of a cell for movement
_____ cell wall 15) system of canals inside a cell
_____ vacuole 16) where photosynthesis occurs
_____ chloroplast 17) first to view cork cells with a simple microscope
_____ cytoskeleton 18) cells lacking a nucleus and membrane-bound organelles




Animal Cell Coloring

I. Directions: Color each part of the cell its designated color.

Cell Membrane(light brown)box Nucleolus (black) box Mitochondria (orange) box
Cytoplasm (light yellow) box Golgi Apparatus (pink) box Lysosome (purple) box
Nucleoplasm (pink) box Flagella (red/blue striped) box Microtubules (dark green) box
Nuclear Membrane(dark brown) box Rough Endoplasmic Reticulum (dark blue) box Ribosome (red)box
  Smooth Endoplasmic Reticulum( light blue) box  

II. Briefly describe the function of the cell parts.

1. Cell membrane ______________________________________________
2. Endoplasmic Reticulum _________________________________________
3. Ribosome ____________________________________________________
4. Golgi Apparatus ____________________________________________________
5. Lysosome ____________________________________________________
6. Microtubule ____________________________________________________
7. Mitochondria ____________________________________________________
8. Nucleus ____________________________________________________