Homeostasis

1. Homeostasis • The goal of living things is to maintain homeostasis (a dynamic equilibrium, health, internal balance) • All life functions interact in order to maintain this!

2. Metabolism • A combination of ALLthe chemicalreactions occurring in an organism • Refers to ALL 8 life processes/metabolic functions!

3. The Cell Theory

4. The discovery of cells and their structure is linked to the development of the magnifying lenses, particularly the microscope in the late 1600’s • Many scientists of the time recognized the importance of cells as building blocks of living tissue. But not until 1838-39 did the general statement of "cell theory" receive general acceptance Learn Biology

5. All living things are composed of cells! • The cells are the basic unit of structure and function in all living things! • Cells arise from pre-existing cells!

6. Exceptions and Problems with the Cell Theory The Cell Theory does NOT explain… • Where did the first cell come from? • What is a virus? It has a non-cellular structure and can only REPRODUCE within a host cell! • Why do mitochondria and chloroplasts have their own DNA? How did it get there?

7. Chloroplast Mitochondria

8. Viruses Are Viruses Alive? - YouTube

9. Categorizing Cells Brainpop • Eukaryotes: complex cells with nuclei and many cell organelles (Animals, plants, fungi and protists) YOU are a Eukaryote! • Prokaryotes: simple cells with no nuclear membrane and few organelles (bacteria)

10. 10 LYSOSOME CYTOPLASM 5 7 CENTRIOLES CELL MEMBRANE 1 8 GOLGI BODY 6 NUCLEOLUS 2 NUCLEUS/ CHROMOSOMES RIBOSOME 4 3 MITOCHINDRIA 11b ROUGH E.R. NUCLEAR MEMBRANE SMOOTH ENDOPLASMIC RETICULUM 11a 9 VACUOLE

11. Nucleolus Nucleus/Chromosomes Golgi Body Chloroplast Nuclear Membrane Smooth ER Cell wall Cell Membrane Rough ER Mitochondrion Large central vacuole Ribosome Cytoplasm

12. Only plant cells have… • Cell Wall provides structure and support for plants and algae • Chloroplasts site for photosynthesis (nutrition in plants and algae) • Large Central Vacuole needed to maintain turgor pressure • They do NOT have centrioles!!!

13. 1. Cell (Plasma) Membrane • Regulates the movement of materials into and out of the cell • “selectively permeable” • Contains Receptors

14. 2. Nucleus • Contains the genetic information (chromosomes, genes, DNA) • Controls and directs the cell’s activities

15. 3. Mitochondria • Site of cellular respiration • Produces ENERGY (ATP!) • “the mighty mitochondria!!!”

16. 4. Ribosomes • Site of protein synthesis (the main job of the cell) - building proteins out of amino acids)

17. 5. Cytoplasm • Watery jellylike medium • Circulates materials around the cell (cyclosis) • Site for many chemical reactions

18. 6. Nucleolus • Builds Ribosomes which make proteins • Contains messenger RNA

19. 7. Centrioles • Used in Cell division (mitosis) • Only in animal cells

20. 8. Golgi Complex (Apparatus) • Packages Proteins made by ribosomes • Sends proteins to final destination either in the cell membrane or outside of the cell

21. 9. Lysosome • Contain enzymes • Fuse w/food vacuoles to help with digestion • “Lyse” rhymes with “slice” • “lysol” breaks apart bacterial cells

22. 10. Vacuole • Storage of water, food, enzymes, waste • Contractile (large central) vacuole helps maintain water balance in plants • (think of a vacuum storing waste)

23. 11. Endoplasmic Reticulum • Transport, storage, and synthesis of substances (mainly proteins) within the cell

24. Smooth Endoplasmic Reticulum • Storage and creation of steroids

25. Rough Endoplasmic Reticulum • Covered in ribosomes (rough) • Takes the proteins and send them to the golgi complex

26. 12. Chloroplast • Site for photosynthesis in plants!

27. 13. Cell Wall • Provides structural support in plant and bacterial cell!

28. 14. Microtubules • Form the cytoskeleton • Gives cell its structure • Allows movement of chromosomes and other organelles inside cell

29. Nuclear Membrane • Surrounds the nucleus allowing certain materials to enter and leave (RNA)

33. Video1 Video 2

34. The Cell Membrane

35. Functions of the Cell Membrane • To REGULATE the movement of molecules from one side of the membrane to another • To recognize chemical signals and communicate with other cells using RECEPTORS!

36. Cell Membrane Structure • “Fluid-Mosaic” model • A double layer of lipids (fats) with many carrier proteins and receptors imbedded in them • Carrier Proteins – transports larger molecules into and out of the cell • Receptors – aid in cell communication as they pick up and receive chemical signals

37. Materials that CAN pass through the membrane are SMALL: • Small enough to move through the lipids: • Carbon dioxide (CO2) • Oxygen (O2) • Water (H2O) • Larger, but can use the protein channels to get through: • Sugars (glucose – C6H12O6) • Amino acids

40. Materials that CANNOT pass through the membrane: • Large molecules like starch

41. Brainpop Types of movement across the membrane The Plasma Membrane - YouTube 1) Passive Transport (Diffusion) • DOES NOT require ENERGY • Moves molecules from high to low concentration (more to less) • Osmosis = the diffusion of water

42. Endocytosis & Exocytosis - YouTube 2) Active Transport • Requires ENERGY! • Moves molecules from low to high concentration (less to more) • Examples:

43. Movement Across the Membrane • When do the molecules move? When there is an unequal amount of solute and water on either side of a membrane

44. 1) Isotonic Solution • when concentration of water and solute are equal on both sides of the membrane • Nothing moves!

45. 2) Hypertonic Solution(high solute) • There is more solute outside the cell, so water moves OUT of the cell, causing the cell to shrivel

46. 3) Hypotonic Solution(low solute) • There is less solute outside the cell (more water), so water moves INTO the cell, causing the cell to swell • Think of hypo = hippo = fat