1. Types of Cells There are two broad groups of cells Organelle
Prokaryotes
Do NOT have membrane-bound organelles
Eukaryotes
DO have membrane-bound organelles
Organelle
Structure within a cell that is surrounded by a membrane and has a specific function for cell survival

2. Prokaryotes No membrane-bound organelles DNA not bound in a nucleus
Many prokaryotes are unicellular
This cell type includes all bacteria

3. Eukaryotes Does Contain membrane-bound organelles
DNA is bound in a nucleus
Eukaryotes may be unicellular (algae and yeast) or multicellular (plants and animals)

4. Plasma Membrane Boundary of the cell
Controls what goes in and out of the cell through the selectively permeable membrane
Keeps some things out and lets some things in
Maintains cell’s homeostasis

5. Plasma Membrane Components– Phospholipid Bilayer
Two layers of phospholipids give the cell a stable yet flexible boundary
Makes up the majority of the plasma membrane
Hydrophilic exteriors
Water “loving”
Hydrophobic interior
Water “hating”
Why?
Structure of the molecule!
Phosphate head = hydrophilic, polar
Hydrocarbon tails = hydrophobic, non-polar

6. Plasma Membrane Components– Membrane Proteins
Carrier
Channel
Marker
Receptor

7. Plasma Membrane Components– Fluid Mosaic Model
The phospholipids move freely within the membrane (but do not flip to the other side)
Fluid
The membrane proteins float on and around the membrane like little boats
Mosaic
These comparisons are why this plasma membrane structure is called the fluid mosaic model

8. Cell Wall Found outside the cell membrane
Gives the cell added support and protection
Made of the carbohydrate, cellulose
This mesh of cellulose is porous and allows anything to pass through
Plants, fungi, and most bacteria (prokaryotes) have cell walls
Animals DO NOT

9. Nucleus and Nuclear Envelope
Controls most of the cell processes and contains the DNA (like the brain of the cell)
In almost all eukaryotic cells (plants AND animals)
Made up of a few parts:
Chromatin- tangled strands of DNA bound to protein, spread throughout nucleus becomes visible chromosomes during cell division)
Nucleolus- small dense region where assembly of the ribosome begins
Nuclear Envelope- double-membrane layer with pores that allow material to move in and out of the nucleus

10. Mitochondria
Transform food energy into high-energy compounds that the cell can use to power growth, development, and movement
The “POWERHOUSE”
Smooth outer membrane and highly-folded inner membrane
The more energy a cell needs, the more mitochondria they may have
For example, a muscle cell would need more mitochondria than a bone cell because it requires more energy to do its job
In eukaryotic cells

11. Chloroplast
Use energy from sunlight to make energy-rich molecules during photosynthesis
Have a double membrane and the green pigment chlorophyll
Inner membrane is folded into disks called thylakoids that are arranged in stacks called grana
Only found in plants and algae

12. Ribosomes
Function: Produce proteins following coded instructions that come from the nucleus
Structure: Made of a large unit and a small unit that only come together when they are making a strand of protein
Can be free or on the Rough Endoplasmic Reticulum
In eukaryotes AND prokaryotes

13. Endoplasmic Reticulum (ER)
Structure: folded membranes within the cytoplasm
“Workplace” of the cell
Rough ER Function:
modifies the proteins that are made on its ribosomes
Smooth ER Function:
Contain special enzymes and help to make lipids for the cell membrane.
In eukaryotes only

14. Golgi Apparatus Structure: flattened system of tubular membranes
Function: Receives modified proteins form the ER and completes the processing of the proteins, packages them in vesicles, and ships them out to their destinations within or out of the cell. Also organizes lysosomes.
In eukaryotes

15. Lysosomes
Small organelles containing digestive enzymes to break down food particles, worn out organelles, bacteria, and viruses into particles that can be used by the rest of the cell
The “Wrecking Crew” of a cell
In eukaryotes

16. Vacuoles
Sac-like structures that store materials such as water, salts, proteins, and carbohydrates
Plants have one large vacuole that also helps give support to flowers and leaves
In eukaryotes
animal
plant

17. Centrioles
Structure: Look like a pair of hollow cylinders which lie perpendicular to each other near the nucleus of the cell.
Function: Plays a role in organizing the mitotic spindle during cell division; plays a role in organizing the basal bodies that build cilia and flagella.
Only in Animal Cells

18. Cilia and Flagella
Function: Helps to move the cell or its outer environment; some organisms use them to capture food.
Cilia – short, numerous, hair-like projections that move in a wavelike motion
Flagella – longer projections that move in a whip-like motion
Major means of locomotion for unicellular organisms

19. Cytoskeleton
A network of protein filaments that helps the cell maintain its shape and helps with cell movement
Microtubules- hollow tubes of protein that maintain cell shape
Microfilaments- long, thin fibers that function in movement and support of cell. Smaller than microtubules

20. Prokaryotes vs. Plants vs. Animals
Organelle
Prokaryotes
Eukaryotes
Plants
Animals
Plasma Membrane
Cell Wall
Nucleus
DNA
Mitochondria
Chloroplasts
Ribosomes                

21. Prokaryotes vs. Plants vs. Animals
Organelle
Prokaryotes
Eukaryotes
Plants
Animals
Endoplasmic Reticulum
Golgi Apparatus
Lysosomes
Vacuoles
Centrioles
Cilia or Flagella            

22. Cell Size
Cells will grow larger to a certain point and then their growth will slow down
Eventually they will stop growing and divide into two smaller cells
These smaller cells will then grow until they divide
Why not just keep growing?

23. Surface Area vs. Volume
Materials must move through the cell by diffusion or by vacuole transport
The further materials travel, the more time and/or energy must be used to move them
Larger cell means a greater surface area for exchanging materials BUT also means a larger volume through which materials must travel
Cells must maintain the proper surface area/volume ratio
Membranes in the cell are often folded to create greater surface area for exchange
Example - Mitochondria