1. CELL STRUCTURE AND FUNCTION
Ch 4
CELL STRUCTURE AND FUNCTION

2. The Cell
The cell is the smallest unit of life that can carry out life processes.

3. Cellular Organization
Section 2 Introduction to Cells
Chapter 4
Cellular Organization

4. Discoveries Leading to The Cell Theory
Robert Hooke – observed cork through a light microscope.
Anton Van Leewenhoek – observed LIVING cells.
Matthias Schleiden – 1883 –plants are made of cells.
Theodor Schwann – 1839 –animals are made of cells

5. The Cell Theory
The cell theory states that all living organisms are made of one or more cells, cells are the basic units of structure and function, and cells come only from pre-existing cells.

6. Two Basic Types of Cells

7. Prokaryotic Cell
Prokaryotic-cells that do not have a nucleus and internal membrane-bound structures
Most unicellular organisms are prokaryotes.
Bacteria

8. Eukaryotic Cell
Eukaryotic-Cells that do have a nucleus and internal membrane-bound structures.
Most multicellular organisms are eukaryotes.
Yeast and algae (unicellular, eukaryotes)
Plant and animal

9. Features Common to Cells:
Cytoplasm – Gel like material that protects, supports and suspends organelles.
All cells have either DNA or RNA or both.

10. Features Common to Cells:
Cell membrane – Semi-permeable allows some materials in and keeps others out. This helps to maintain cellular homeostasis.

11. Structure of the Plasma Membrane
Phospholipid Bilayer -2 layers ofphospholipids.
Phospholipid- phosphate head attached to two lipids (fattyacid tails).
Polar phosphate group allows membrane to interact with its environment.
Fatty acid tails create a water-insoluble layer in the middle which is non-polar.
Fluid mosaic model-membrane is flexible
Cholesterol-keeps fatty acid tails from sticking together
Transport proteins-allow needed substances to move through the membrane

12. Parts of the Cell
Chapter 4

13. Nucleus Nucleolus-makes ribosomes
Ribosomes-site where proteins are made
Can be found floating in the cytoplasm or attached to endoplasmic reticulum
“Command center”
Surrounded by a nuclear envelope
Contains genetic material:
chromatin
chromosomes

14. Endoplasmic Reticulum (ER)
Smooth Endoplasmic Reticulum (SER)
Produce and store lipids
Series of folded membranes allow a large amount of work to be done in a small amount of space
Transportation unit for the cell
Rough Endoplasmic Reticulum (RER)
Ribosomes attached
Protein synthesis

15. Golgi Apparatus Vesicles
Flattened tubular membranes
Packaging plant
Modify, sort, package, and transport proteins throughout the cell

16. VACUOLES Storage sacs Temporary storage of materials
Store food, enzymes, waste
Plant cells have one large vacuole.
Animal cells have many small vesicles.

17. LYSOSOMES Contain digestive enzymes
Digest excess or worn organelles, food particles, viruses, and bacteria
Surrounded by membrane that prevents it from destroying the cell
Can burst causing cell death

18. Mitochondria Chapter 4 Cellular respiration -converts food into energy
Cell “Powerhouse”
Number of mitochondria depends upon the function of the cell
Ex: muscles cells have more mitochondria than fat cells

19. Centriole
Help with cell reproduction
Only found in animal cells

20. Plastids – Color pigments of cells
Examples:
Chloroplast – Located in plant cells, some bacteria, and protists.
Capture light energy to produce and store food
Contain chlorophyll-green pigment that traps light energy

21. Features Common to Cells:
Cytoskeleton – tiny fibers that give structure and support to the cell.
Microfilament- thin and tubular…support the cell membrane.
Microtubule- thick and tubular also branched. Act as “rails” on which materials move through the cell.

22. Cilia and Flagella Flagella-long, whip-like projections
Aid in movement and feeding
Composed of microtubules
Cilia-short, numerous hair-like projections that move in a wavelike motion

23. Cell wall Rigid outer covering PLANT CELLS
Located outside the cell membrane
Provides support and protection
Helps produce turgor pressure

24. Animal Cell
Plant Cell

25. Plant cell vs. Animal Cell

26. Plant vs Animal cells Animal Cell vs. Plant cell Animal Cell
DO contain centrioles.
DO NOT contain a cell wall or plastids.
Plant Cell
DO contain a cell wall, plastids, and a large central vacuole.
DO NOT contain centrioles