1. Ch 6: Cells

2. History of Cytology 1665 – Robert Hooke 1673 – Anton van Leeuwenhoek
Viewed cork
Named “cells”
1673 – Anton van Leeuwenhoek
Unicellular pond organisms – named “animalcules”
First to see bacteria and yeast
1833 – Robert Brown discovered nucleus

3. Cell Theory 1838 – Matthias Schleiden 1839 – THeodor Schwann
All plant parts are composed of cells
1839 – THeodor Schwann
All animal tissues are composed of cells
1858 – Rudolph Virchow
All cells come from other cells
Cell Theory:
1) All living things are composed of 1 or more cells
2) Cells are the basic unit of structure and function
3) All cells are produced from existing cells

4. Cells All cells have: Plasma membrane (cell membrane)
regulates materials in/out of cell
Composed of phospholipid bilayer
Contains different proteins
Cytoplasm
everything inside the cell membrane
Medium for chemical rxns
Cytosol – fluid portion
Chromosomes (Genes) - DNA
Ribosomes –site of protein synthesis

5. Cell Size – must be small
To efficiently exchange materials in/out of cell membrane
Cell surface is the only area of interaction w/ environment
To transport materials inside of cell
Efficiency depends on surface area to volume ratio
Small cells function more efficiently than larger cells!

6. Surface Area to Volume Ratio

7. Prokaryotic Cells DNA is located in nucloid region (NO NUCLEUS)
Does not contain membrane bound organelles
Only Eubacteria and Archeabacteria Kingdoms

8. Prokaryotic Cell

9. Evolution of Eukaryotic Cells
Theory of Endosymbiosis – one prokaryotic cell engulfed another and did not digest it, :. Forming a double membrane… successful relationship
Evidence: Chloroplasts and mitochondria each have their own separate DNA and can reproduce on their own, and are similar to prokaryotic cells

10. Endosymbiosis

11. Eukaryotic Organelles
Nucleus – contains chromosomes
Nucleolus
contain materials for RNA
Makes ribosomes
Nuclear Membrane w/ nuclear pores
Nucleoplasm – jelly like material w/in nucleus
Mitochondria
Powerhouse of the cell
Releases E stored in food
Produces ATP

12. Eukaryotic Transport System
Ribosomes – site of protein synthesis
Free floating in cytoplasm (free)
Attached to ER (bound)
Endoplasmic Reticulum (ER)
An internal channel system
Rough ER – has ribosomes on surface, aids in transporting proteins
Smooth ER – involved in making lipids and breaking down toxic substances

13. Eukaryotic Transport System
Vesicles – membrane buds off ER w/ proteins or lipids enclosed
Lysosome – contains digestive enzymes to break down macromolecules and worn out cell parts
Peroxisome - contains enzymes that converts fat to carbohydrates (from smooth ER)
Golgi body (complex/apparatus) – packaging and distribution center of the cell
Cis golgi – arrival side
Trans golgi – departure side

15. Cytoskeleton Cytoskeleton – internal framework
Mesh-like network of protein fibers
Supports cell shape and anchors organelles
Microtubules – hollow tubes move chromosomes during cell division by forming centrioles (animal cells only)
Actin – long intertwined microfilaments that contract or expand to determine shape
Intermediate fibers – fibrous protein cables that anchor ribosomes and enzymes

16. Cytoskeleton

17. Cellular Movement
Flagella – long threadlike microtubules (whip-like tail)
Cilia – numerous short and tightly packed microtubules

18. Intercellular Junctions
Plants
Plasmodesmata – perforated channels in plant cell wall allowing cytosol, water and small solutes to pass freely
Animals
Tight junctions – forms tight seal between cells
Desmosomes – anchor cells together in strong sheets
Gap junctions – cytoplasmic channels between adjacent cells allowing communication

19. Animal Cells only Extracellular Matrix (ECM) Centrioles
Collagen – strong glycoprotein fibers
Proteoglycans – network of glycoproteins
Fibronectin – attaches ECM to Integrins
Integrins – membrane proteins bound to ECM and interior microfilaments
Centrioles
composed of microtubules
Aid in moving chromosomes during cell division
Centrosome – 2 centrioles

21. Plant Cells Only Cell Wall Central Vacuole Chloroplast
Extra protective layer
Cellulose - maintains structure
Central Vacuole
Stores water, ions, nutrients, and waste materials
Controls pressure w/in cell
Tonoplast – membrane surrounding vacoule
Chloroplast
Contains chlorophyll – photosynthetic pigment
Uses water, carbon dioxide and sunlight to make food in the form of glucose