1. Cells

2. Levels of cellular organization
Atom
Molecule
Organelle
Cell
Tissue
Organ
Organ System
Organism

3. Cells
Prokaryotic
Bacteria
Eukaryotic
Animal
Plant

4. Division of Cells Eukaryotic Cells Literally means “True nucleus”
Have a nucleus
Complex Cells
Have membrane-bound organelles
Organisms made of eukaryotic cells are called “eukaryotes”
Examples: Animals, Plants, Fungi, Unicellular organisms like paramecium and amoeba

5. Cellular Components Cytoplasm Cytoskeleton
Gel-like substance within the cell where organelles are found
Cytoskeleton
“Cell skeleton”
Network of protein fibers that maintain the shape of cell
Composed of three networks of fibers
Microtubules: largest; hollow tubes made of protein; determine cell shape; scaffolding
Intermediate Filaments: Provide strength of cell
Actin Filaments: smallest; contractile string-like proteins that allow for cell movement

7. Cellular Components Cell Membrane Cell Wall
Semi-permeable barrier that encloses the cell
Regulates what enters and exits the cell
Provides protection
Found in all types of cells
Cell Wall
Porous, rigid barrier found surrounding the cell membrane
Adds additional layer of support and protection
Not found in animal cells

8. Organelles
Nucleus
Houses the genetic material (DNA) needed for replication of the cell
“Control Center” of the cell
Contains the instructions for the creation of proteins (made from DNA)
Exterior: Surrounded by nuclear envelope: double-layered membrane that encloses the DNA; contains nuclear pores: small openings that allow for the passage of molecules between the cytoplasm and the nucleus
Interior: DNA in the form of chromatin (string-like)
Nucleolus: where ribosomes are made; very dense region

9. Organelles Endoplasmic Reticulum Ribosomes
A grouping of sac-like structures
Two Types of ER:
Rough ER: contain ribosomes (creating ‘rough’ appearance); involved in the process of protein synthesis
Smooth ER: no ribosomes; involved in lipid synthesis
Ribosomes
Location where proteins are made (protein synthesis)

10. Organelles Golgi Apparatus
Looks like a stack of membranes (pancake-like appearance)
Modifies, sorts and packages proteins received from the ER.
Break off from the golgi apparatus; floats freely in the cell or travels to cell membrane where it will eventually exit the cell.
Creation of lysosomes

11. Organelles
Lysosomes
Contain enzymes necessary for digestion of cell food or waste
Can break down lipids, carbs, proteins
Digest non-functional organelles, ‘cleaning up’ the cell

13. Organelles
Vacuoles
Sac-like structure responsible for storage of various materials (e.g. water, carbs, proteins, etc.)

14. Organelles Mitochondria The “Powerhouse” of the cell
Convert food energy into energy that is used by the cell itself (for growth, development, movement, etc.) via cellular respiration
ATP (Adenosine Triphosphate)
Complex structure

15. Organelles Chloroplast Site of photosynthesis
Energy from sun is captured and converted into chemical energy
Contain the pigment chlorophyll which absorbs solar energy used in photosynthesis
Responsible for the green color of plants

16. Organelles Centrioles Made of microtubules Located near nucleus
Organize microtubules within the cytoskeleton prior to cell division

17. Division of Cells Prokaryotic Cells Include Bacteria & Archaea
Literally means “before nucleus”
So-have no nucleus
Lack membrane-bound organelles
Simpler and much smaller than Eukaryotes
Organisms made of prokaryotic cells are called “prokaryotes”

18. Structure of Prokaryotes
Three basic shapes
Bacilli: rod-shaped bacteria
Cocci: Spherical-shaped bacteria
Spirilla: Spiral-shaped bacteria; flexible

19. Prokaryotic Cell Parts: Interior
Do prokaryotic cells have DNA if they lack a nucleus?
Nucleoid: a region within the cytoplasm of the cell in which the DNA is located; center of the cell (no membrane encloses the DNA)
Cytoplasm
Semifluid, gel-like solution encased within the cell membrane of the cell

20. Interior
Ribosomes
Made of two subunits (each containing a combination of various proteins and rRNA) which work together to synthesize protein
Located throughout the cytoplasm

21. External Layers Cell Membrane Cell Wall Glycocalyx
Regulates the entrance and exit of various substances in and out of the cytoplasm
Cell Wall
Provides shape, structure, and support for cell
Glycocalyx
The outermost layer of bacterial cells; gel-like protective layer

22. External Structures Flagella Fimbriae Conjugation Pili
Allows for cell movement
Long, rotating filament that propels the cell forward
Fimbriae
Hair-like bristles located on the external surface of the cell
Allow cells to attach to surfaces
Conjugation Pili
Tube-like structures that allow for bacteria to pass DNA from cell to cell; usually larger and less numerous than fimbriae