1. Chapter 3 CELLS

2. A. The Early Years ] Robert Hooke (1660) F 1st person to see the outlines of cells ] Antonie van Leeuwenhoek (1673) F developed high magnification lenses F 1st record of microorganisms ] Matthias Schleiden & Theodore Schwann (1839) & Rudolph Virchow (1855) F contributed to the cell theory

3. Cell Theory 1. All living things are composed of cells. [Schleiden & Schwann] 2. All cells come from preexisting cells. [Virchow]

4. B. Cell Size ] Most are 1-100  m in diameter ] Smallest? ] Largest? ] Why can’t cells grow to be as large as a car? - surface area/volume ratio - as cell grows, its volume increases more rapidly than its surface area

6. C. Types of Cells 3 basic types: F Bacterial F Archaean Prokaryotic F Eukaryotic

7. 1. Bacterial cells F 1-10  m in diameter F NO membrane-bound organelles F 1 circular DNA molecule located in nucleoid region F plasma membrane, cytoplasm & ribosomes F most have a cell wall (peptidoglycan) F may have a polysaccharide capsule Ex. bacteria & cyanobacteria

9. 2. Archaean cells F 1-10  m in diameter F NO membrane-bound organelles F cell walls lack peptidoglycan F have characteristics of both bacteria & eukaryotic cells Ex. methanogens, extreme halophiles & extreme thermophiles

10. 3. Eukaryotic cells F 10-100  m in diameter F nucleus & other membrane-bound organelles F 2 or more linear DNA molecules located in nucleus F plasma membrane, cytoplasm & ribosomes F some have a cell wall (cellulose or chitin) Ex. plants, animals, fungi, protista

11. Generalized Generalized Animal Cell Plant Cell

12. D. Organelles of Eukaryotic Cells Organelles compartmentalize a cell’s activities. 1. Nucleus F surrounded by a double membrane (nuclear envelope), perforated with nuclear pores F contains DNA & nucleolus (stores RNA nucleotides) F functions to separate DNA from rest of cell

13. Nucleolus

14. 2. Endoplasmic reticulum (ER) F interconnected network of membranes extending from nucleus to plasma membrane

15. Rough ER - studded with ribosomes F site of protein synthesis (most will be exported out of the cell) Free ribosomes in the cytoplasm synthesize proteins that remain in cell. Smooth ER - lacks ribosomes F site of lipid synthesis F contains enzymes that detoxify drugs & poisons

16. 3. Golgi apparatus F stacks of membrane-enclosed sacs

17. Functions: F links simple carbohydrates together to form starch F links simple carbohydrates to proteins (glycoprotein) or lipids (glycolipid) F completes folding of proteins F temporarily stores secretions (milk)

18. Organelle interaction in a mammary gland cell.

19. F #/cell varies F contain DNA F inherited from female parent F site of cellular respiration (production of ATP) 4. Mitochondria F double-membrane v outer is smooth v inner is highly folded (cristae)

20. 5. Chloroplasts F possess 3 membranes v outer/inner membranes surround stroma v 3rd membrane system folded into flattened sacs (thylakoids) F #/cell varies F contain DNA F found in plants & protists F function in photosynthesis

21. 6. Lysosomes (suicide sacs) F vesicles containing > 40 types of digestive enzymes F function to recycle damaged organelles, break down cellular byproducts & destroy invading microbes

22. 7. Peroxisomes F vesicles containing several types of enzymes (produced in cytoplasm) F found in all eukaryotic cells F function to help cell use oxygen & metabolize potentially toxic compounds

23. E. The Endosymbiont Theory Proposes that chloroplasts and mitochondria evolved from once free-living bacteria engulfed by larger archaea. Based on fact that mitochondria & chloroplasts resemble certain bacteria (size, shape, membrane structure & method of making proteins).