1. Chapter 5 Cell Structure and Function

2. I. The history of cell study A. Robert Hooke—1665—coined the word cell, looked at cork cells B. Robert Brown—1831— discovered the "nucleus"

3. I. The history of cell study C. Theodor Schwann—1838— viewed animal cells in cartilage 1. Cells are the elementary particles of plants and animals D. Mattias Schleiden—Cells are the fundamental basis of life E. Virchow—1858—All cells come from cells

4. I. The history of cell study F. Cell theory 1. All living things are composed of one or more cells 2. Cells are the basic unit of structure and function 3. All cells come from preexisting cells

5. II. Attributes of cells A. Cell size 1. 1–100µm 2. Why is there a limit to cell size? a. Surface-to-volume ratio b. Distance from surface to center

6. II. Attributes of cells B. Cell types 1. Prokaryotic—no nucleus, circular DNA, ribosomes 2. Eukaryotic—larger, nucleus, linear chromosomes, membranous organelles

7. III. Cell structure A. All cells possess a plasma membrane, cytoplasm, genetic material 1. Plasma membrane has phospholipid bilayer, embedded glycoproteins a. Isolates cytoplasm from environment b. Regulates molecular movement into and out of cell c. Interacts with other cells/environment

8. III. Cell structure A. All cells possess a plasma membrane, cytoplasm, genetic material (cont.) 2. Genetic material—DNA, found in the nucleus (of eukaryotes) 3. Cytoplasm—water, salts, organic monomers and polymers a. Contains organelles

9. III. Cell structure B. Organelles 1. Endoplasmic reticulum consists of folded membranes attached to the nucleus a. Rough ER is site of protein synthesis and protein secretion 2. Ribosomes assemble amino acid monomers into polypeptide chains a. Associated with the ER b. Composed of RNA and proteins

10. III. Cell structure B. Organelles (cont.) 3. Golgi apparatus (dictyosomes) are membranous sacs associated with ER a. Processing and transport of proteins, lipids b. Synthesis and transport of polysaccharides 4. Lysosomes are Golgi-derived vesicles containing digestive enzymes

11. III. Cell structure B. Organelles (cont.) 5. Mitochondria provide energy for cellular functions (respiration) a. Membrane bound, numerous b. Matrix/ cristae c. Have their own DNA and ribosomes; self-replicate

12. III. Cell structure B. Organelles (cont.) 6. Plastids a. Chloroplasts—function in photosynthesis 1) Green—contain chlorophyll pigment 2) Stroma/grana (thylakoid stacks) 3) Have their own DNA and ribosomes; self-replicate 4) Up to 100 per cell b. Mitochondria, plastids, and the endosymbiont hypothesis

13. III. Cell structure B. Organelles (cont.) 7. Vacuoles a. Large, water-filled spaces (cell sap) b. Can take up over 90% of cell volume c. Surrounded by tonoplast (a single membrane)

14. III. Cell structure B. Organelles (cont.) 7. Vacuoles (cont.) d. Functions: 1) Storage of red/blue anthocyanins, acids, salts, wastes 2) Maintain cell pressure (turgor pressure)—wilting

15. III. Cell structure B. Organelles (cont.) 8. Nucleus is control center of the cell a. Membrane bound (nuclear envelope) b. Contains nucleoli; synthesizes ribosomal RNA c. DNA in chromosomes (DNA and proteins)

16. III. Cell structure C. Cell walls in plant cells, prokaryotic cells, fungi 1. Polysaccharide composition 2. Function: support, protection

17. III. Cell structure D. Cytoskeleton of protein fibers (microfilaments, microtubules) 1. Cell shape 2. Cell movement 3. Organelle movement 4. Cell division

18. III. Cell structure E. Cilia and flagella are protein microtubule extensions of the plasma membrane 1. Aid in movement of simple organisms

19. IV. Cell function A. Protein assembly B. Metabolism