1. Cell Structure & Function

2. Definition of Cell
A cell is the smallest unit that is capable of performing life functions.

3. Examples of Cells Amoeba Proteus Plant Stem Bacteria Red Blood Cell
Nerve Cell

4. Prokaryotic Eukaryotic
Two Types of Cells
Prokaryotic
Eukaryotic

5. Prokaryotic
Do not have membrane bound organelles (structures surrounded by membranes)
Few internal structures
One-celled organisms
Example: Bacteria

6. Eukaryotic Cells Contain organelles surrounded by membranes
Includes most living organisms both single & multi-cellular
Carry out more specialized functions than prokaryotic cells b/c of their complex organization
Animal
Plant

7. “Typical” Animal Cell

8. “Typical” Plant Cell

9. Organelles “little organs”
Cell Parts
Organelles
“little organs”

10. Surrounding the Cell

11. Cell Membrane Also called the Plasma Membrane
Outer membrane of cell that controls movement in and out of the cell
Double layer called the phospholipid bilayer

12. Cell Wall Most commonly found in plant cells, fungi cells & bacteria
Supports & protects cells
Double layer

13. Flagella & Cilia Flagella- whip-like projections
Cilia- hair-like projections
Both are used for movement; composed of cytoskeleton filaments & protein; covered in an extension of the cell membrane

14. Inside the Cell

15. Nucleus Directs cell activities
Separated from cytoplasm by nuclear membrane
Contains genetic material (DNA) inside the nucleolus

16. Nuclear Membrane Surrounds nucleus Made of two layers
Openings called nuclear pores allow material to enter and leave nucleus

17. Chromatin/Chromosomes
In nucleus
Chromatin is DNA & protein in a loose network of bumpy threads (condenses to form chromosomes during cell division)
Contain instructions for traits & characteristics

18. Nucleolus Inside nucleus Contains RNA to build proteins
ribosome parts are
made here

19. Cytoplasm Gel-like mixture surrounded by cell membrane
Organelles are supported by the cytoplasm
Site of most cellular activities (like the factory area of the cell)

20. Endoplasmic Reticulum
System of canals that coils & twists through the cytoplasm
Moves materials around in cell
Smooth ER: lacks ribosomes, functions in lipid metabolism (making & breaking down cholesterol and fats) and detoxification of drugs and pesticides

21. Endoplasmic reticulum (cont.)
Rough ER:
Has ribosomes on the surface
Proteins made by the ribosomes enter the rough ER then fold into their functional 3-dimensional shape. They are then transported to other areas of the cell in vesicles.

22. Ribosomes Each cell contains thousands Makes proteins
Floating free throughout the cell

23. Mitochondria
Produces energy (ATP) by breaking down food (cellular respiration)
Regulates cellular metabolism
Surrounded by 2 membranes
Has its own DNA & ribosomes!
‘busy’ cells have hundreds of mitochondria

24. Golgi Bodies or Golgi Apparatus
Stack of flattened membrane bound sacs
Major function is to modify & package proteins
Modifies, sorts, and packages materials for export from the cell

25. Lysosome Contains powerful digestive enzymes
Digestive ‘factory' for proteins, fats, and carbohydrates
Abundant in cells that dispose of bacteria & cell debris
Cell is digested if a lysosome explodes

26. Peroxisomes
Most important function is to convert free radicals into hydrogen peroxide (H2O2)
If left to accumulate, free radicals can have devastating effects on cells

27. Vacuoles/ Central Vacuole
Membrane-bound sacs for storage, digestion, and waste removal
Contains water, ions, nutrients, & wastes
Very large in plants; maintain plant shape by holding lots of water

28. Chloroplast A plastid found in plant & algae cells
Contains green chlorophyll
Where photosynthesis takes place
Flattened sacs are called thylakoids

29. Cytoskeleton
Elaborate network of protein structures that extends throughout the cytoplasm
Acts as the cells “bones & muscles” by providing an internal framework that determines cell shape, supports other organelles, and provides a route for intracellular transport
Made up of microfilaments,
microtubules, &
intermediate
filaments

30. Centrioles
Rod-shaped structures that direct the formation of spindle fibers during mitosis & meiosis
Made of microtubles

31. Vesicles
These are not actually organelles. This is a generic term for any material that is enclosed in a membrane. Vesicles are pinched off from the golgi body, cell membrane, and ER. They may contain hormones, proteins, nutrients, etc.