1. Unit 3 - Cells Chapter 7 Cell Structure & Function

2. Brief history Hooke (1660’s) Leeuwenhoek (1670’s) Schleiden & Schwann(1830’s) Virchow (1850’s)

3. Cell Theory (based on 200+ years of discoveries) A. all living things are composed of cells B. cells are the basic unit of structure & function of all living things C. new cells are produced from existing cells

4. Cell Types  Prokaryotic cells =  smallest, no true nucleus, ribosomes only  Ex: bacteria Eukaryotic cells = – large, multicellular, true nucleus, many specialized organelles –ex: protists, fungi, plants & animals

5. 1. Nucleus = directs cell activities a) N. Envelope (with pores) outer boundary b) Chromosomes = (contain DNA) carry genetic code c) Nucleolus (contain RNA) produces ribosomes chromatin

6. 2. Endoplasmic reticulum = an interconnecting system of “pathways,” for transport May be Rough ER (with ribosomes) or Smooth ER (without ribosomes) 3. Ribosomes = small bodies on ER to produce protein

7. 4. Golgi = flattened compartments with vesicles for secretion (packaging & shipping)

8. 5. Lysosomes = small filled sacs, for digestion

9. 6. Vacuoles = large, “hollow” sacs (in plants) for storing liquids

10. 7. Mitochondria = rod-shaped with folds, for releasing energy (ATP) by respiration

11. 8. Chloroplasts = oval with green pigment for making food by photosynthesis

12. 9. Cytoskeleton = hollow fibers for support & shape to move cytoplasm

13. 10. Plasma Membrane – outer boundary of cytoplasm Semipermiable (only certain molecules enter & leave) Outside of cell Inside of cell (cytoplasm) Cell membrane Proteins Protein channel Lipid bilayer Carbohydrate chains

14. a. Phospholipid bilayer a double layer that is an effective barrier for most molecules 1) Hydrophobic = “water fearing” center tails prevent most things from entering 2) Hydrophilic = “water loving” heads attract water to edges of membrane

15. b. Embedded Proteins 1) Channels “gates” to interior for transporting into & out of cytoplasm 2) Receptors “windows” for gathering information about cell surroundings 3) Markers “name tags” that identify type of cell to others

16. current (Concentration gradient) Passive or Active transport?

17. Passive vs Active transport: which requires energy output?

18. Passive Transport Click here for D:\Content\Chapter 07C.mpgD:\Content\Chapter 07C.mpg

19. c. Types of passive transport 1) Diffusion random spread of molecules from higher to lower concentration Examples?

20. 2) Osmosis Diffusion of water through a membrane Examples?

21. 3) Types of osmotic solutions a) Hypertonic More solutes = less water = water moves out & cell shrinks b) Hypotonic Less solutes = more water = water moves in & cell expands c) Isotonic Equal solutes & water, so equal movement of water & cell is stable

22. Types of solutions Click here to view Filmclip

24. Plant cells in Isotonic solution

25. Cells in various solutions LYSE TURGID NORMAL FLACCID PLASMOLYZE Plant, fungus, algae, bacteria animal Hypotonic Isotonic Hypertonic

26. Types of Active Transport Click here to view flimclip

27. 4. Types of Active Transport a. Endocytosis cell brings particles into cytoplasm 1) Pinocytosis small particles (liquids) are brought in by vesicles

28. 2) Phagocytosis large particles (food or bacteria) are surrounded & engulfed by cell membrane Examples = an ameba feeding & a white blood cell destroying an invader

29. b. Exocytosis cell deposits particles outside of cytoplasm 1) Secretion = cell products given off 2) Excretion = wastes products given off