1. Unit 2:Cell Structure and Function Section 1 The History of Cell Biology Section 2 Introduction to Cells Section 3 Cell Organelles and Features Section 4 Unique Features of Plant Cells

2. Objectives Name the scientists who first observed living and nonliving cells. Summarize the research that led to the development of the cell theory. State the three principles of the cell theory. Explain why the cell is considered to be the basic unit of life.

3. Sect 1: Discovery of Cells All living things are made up of one or more cells. A cell is the smallest unit that can carry on all of the processes of life.

4. Discovery of Cells Robert Hooke 1665 used microscope to examine cork. Coined the term “cell”.

5. Discovery of Cells Anton van Leeuwenhoek 1673, observed living cells. Called cells animalcules- current day protists.

6. Cell Theory All living organisms are made of one or more cells. Cells are the basic unit of structure and function in an organism. Cells come from the reproduction of existing cells.

7. Cellular Basis for Life All living things: are made of organized parts obtain energy from their surroundings perform chemical reactions change with time respond to their environment reproduce. maintain constant internal environment

8. Sect. 2: Objectives Explain the relationship between cell shape and cell function. Identify the factor that limits cell size. Describe the three basic parts of a cell. Compare prokaryotic cells and eukaryotic cells. Analyze the relationship among cells, tissues, organs, organ systems, and organisms

9. Sect 2: Cell Diversity Shape: reflects function

10. Sect 2: Cell Diversity (cont’d) Size: limited by surface-to-volume ratio -allows for quick transport of materials into and out of the cell

11. Basic Parts of a Cell The three basic parts of a cell: plasma membrane: covers cell’s surface; acts as a barrier between inside and outside of cell. cytoplasm: region within plasma membrane; includes the fluid, the cytoskeleton, and all organelles except the nucleus nucleus: membrane-bound organelle that contains cell’s DNA.

12. Two Basic Types of Cells Prokaryotes: lack a nucleus and membrane-bound organelles.

13. Two Basic Types of Cells Eukaryotes: have a nucleus and membrane-bound organelles

14. Prokaryotes vs Eukaryotes Prokaryote Eukaryote

15. Cellular Organization Colonies: collection of genetically identical cells that exist together.

16. Cellular organization (cont’d) True multicellularity: specialized cells- tissue- organs- organ system, organism

17. Sect 3 Objectives: Describe the structure and function of a cell’s plasma membrane. Summarize the role of the nucleus. List the major organelles found in the cytosol, and describe their roles. Identify the characteristics of mitochondria. Describe the structure and function of the cytoskeleton.

18. Sect. 3: Cell Organelles and Features Plasma Membrane: consists of a phospholipid bilayer and embedded membrane proteins Polar, hydrophilic head points outward toward water Two hydrophobic tails point inward away from water Sterols make membrane firm and prevent freezing

19. Plasma Membrane

20. Nucleus Nucleus: directs the cell’s activities and stores DNA; surrounded by a double membrane called the nuclear envelope

21. Nucleolus Nucleolus: place within nucleus where DNA is concentrated when it is in the process of making ribosomal RNA.

22. Mitochondria Mitochondria: harvest energy from organic compounds and transfer it to adenosine triphosphate- ATP. have own DNA may be a result of a symbiotic relationship between prokaryote and eukaryote cells.

23. Ribosomes Ribosomes: either free in cytoplasm or attached to the rough ER; play a role in protein synthesis.

24. Endoplasmic Reticulum- ER ER: system of membranous tubes-cisternae; functions as an intracellular path molecule transport. Two types: rough ER: makes phospholipids, proteins; most abundant in digestive glands and antibody-producing cells. smooth ER: builds lipids, helps detoxify drugs, poisons in liver, kidney cells; produces estrogen and testosterone in ovaries and testes.

26. Golgi Apparatus Golgi apparatus/body/complex: stacks of flattened membranes, processes and packages proteins

27. Vesicles Vesicles: small, migrating “packages” of needed materials. Lysosomes: bud from golgi body, carry digestive enzymes needed for breakdown of proteins, nucleic acids, or worn- out cells.

28. Protein Synthesis Major function of cell Requires work of ribosomes, rough ER, Golgi apparatus, and vesicles… 1.Ribosomes assemble proteins on rough ER. 2.Vesicles transport proteins to Golgi apparatus. 3.Golgi modifies proteins, repackages them in new vesicles. 4.Vesicles release proteins for trip outside cell. 5.Vesicles with enzymes stay within cell.

29. Cytoskeleton Cytoskeleton: protein fibers that help cells move and maintain their shape. cilia and flagella: hairlike structures that extend from cell surface; aid in movement. centrioles: microtubules in animal cells, play role in cell division.

30. Sect 4: Unique Features of Plant Cells Cell walls, central vacuoles, and plastids

31. Cell Wall Rigid layer outside of cell membrane Contains cellulose, proteins, pores for water ions.

32. Central Vacuole Reservoir for water, enzymes, wastes Can make up to 90% of cell interior Loss of water causes plants to wilt

33. Plastids Surrounded by double membrane Contain their own DNA most important: chloroplasts, chromoplasts

34. Chloroplasts Use light energy to make carbohydrates from CO ₂ and H₂O Thylakoids contain chlorophyll, main molecule that traps light energy for photosynthesis

35. Chromoplasts Contain colorful pigments ex.s: carotene, xanthophyll