Cells

2. Cells What did Robert Hooke call the boxes that he observed in cork?

3. Why should I care?

4. So, what is a cell? • Smallest functional unit that can support life • A bacterium is only one self-sustaining cell • You are made up of trillions of interdependent cells • Too small to see without a microscope

5. Problem? • Miss Apgar wants to view a bacterial cell that needs to be magnified 1000 times in order to see it. Her compound light microscope has a 10X ocular lens. Which objective lens should she use to see the bacterium? _____________ • Where is the ocular lens? ____________________ • Where is the objective lens? _________________

6. What do we remember about microscope history? • Robert Hooke • Named the cell • Cell – Structural and functional unit of life • Made sketches of the microscopic world

7. Anton van Leeuwenhoek • Perfected a single lens microscope • Examined water and milk • Called creatures he saw “cavorting wee beasties”

8. Some More History • Matthias Schleiden • Studied plants • Determined that all plants are made of cells • Theodor Schwann • Studied animals • Determined that all animals are made of cells

9. Some More History • Rudolf Virchow • German physician • Proposed that cells divide to form new cells • Used his theory to diagnose patients • Father of pathology

10. Cell Theory - putting their work together • All organisms are made of cells • It can be one solitary cell or many cells working together • The cell is the basic unit of organization in living organisms • Even in complex organisms like humans, the cell is the basic unit of life • All cells come from pre-existing cells • Cells grow and divide, passing genetic information to the next generation of cells

11. How do we know that cells come from other cells?

13. Two types of cells… • Prokaryotic cells • Simple interior • Considered to be the prototype • Eukaryotic cells • Complex interior • Considered to be the latest update

14. Prokaryotes • Simple interior • DNA in central nucleoid region • Cellular functions happen in open space • Single cell organisms • Bacteria • Archaea

16. Inside a Prokaryote The cytoplasm is where cell life takes place DNA is concentrated in the nucleoid region Ribosomes make proteins The Flagellum provides transportation Capsule, cell wall, and cytoplasmic membrane provide protection and support

17. Eukaryotes • Complex interior • DNA is neatly packaged and protected by nucleus • Organelles perform cellular functions • Single and multiple cell organisms • Amoebas – single celled • You are a EU-karyote

18. 4 Kingdoms • Animalia • Plantae • Fungi • Protista

19. Inside a Eukaryote • The cytoplasm is where the organelles are located • DNA is housed in the nucleus • Ribosomes make proteins • There are many other organelles each covered by a membrane • Each organelle has its own function • Cytoplasmic membrane provides protection

20. Venn Diagram Time… turn to page 22!

21. Prokaryotic Cells Eukaryotic Cells

22. Your task now… • Look on page 11 in your packet • Read “The Origin of the Eukaryotic Cell” (pgs 19-20) • Answer questions pages 21 and 22 • Homework if you do not finish!!

24. More on the Eukaryote cell • Important terminology • DNA – genetic material • Organelle – cellular structures that carry out specific functions • Means “little organ” • Let’s break it down…

25. First up: the plasma membrane

26. The Cell Membrane • The cell membrane is selectively permeable • Some things can pass but others can’t • Cell membranes are made from a phospholipidbilayer

27. Outside of cell Carbohydrate chains Proteins Cell membrane Inside of cell (cytoplasm) Protein channel Lipid bilayer PhospholipidBilayer Structure • Each phospholipid has a polar head and two nonpolar tails • Polar head is attracted to water • Nonpolar tails are repelled by water

28. PhospholipidBilayer Function • Allows some things in and not others • Polar molecules do not easily pass • H2O is an exception because it is small • Keeps the outside out and the inside in • The plasma membrane is always in motion

29. Fluid Mosaic Model • Fluid • Membrane is in motion • Membrane is flexible • Mosaic • There are molecules embedded in the bilayer • The scattered arrangement looks like a mosaic

31. Animal Cells vs. Plant Cells • Eukaryotic cell which makes up tissues in animals • Lack cell walls and chloroplasts, and have smaller vacuoles. • Appears to be circular because of the lack of a rigid cell wall. • Eukaryotic cell that makes up plants • Cell Wall • Chloroplast • Large Vacuoles

32. Animal Cell

33. Plant Cell

34. Cell Wall Mesh of fibers that surrounds the plasma membrane Protects and supports the cell Made of carbohydrate, cellulose

35. Cytoplasm Semi-fluid material inside the plasma membrane Consists of cytosol and the cellular organelles (all organelles except the cell nucleus) Cytosol - fluid in which the cellular organelles are suspended

36. Cytoskeleton Cytoskeleton in Red and Green Network of long, thin protein fibers provide an anchor for organelles Microtubules-long hollow cylinders that assist in moving substances within the cell Microfilaments-thin threads that give the cell shape and enable the cell to move

37. Nucleus • Contains genetic material (DNA) • Nuclear envelope • Nuclear pores allow substances in and out • Nucleolus in center • Very dense center

38. Ribosomes • Produce proteins • Made of RNA and protein • Made in the nucleolus • Some float freely in the cytoplasm • Others attach to endoplasmic reticulum

39. Endoplasmic Reticulum • Interconnected network of tubules

40. Two types of Endoplasmic Reticulum Rough ER Smooth ER No ribosomes Produces complex carbohydrates and lipids • Where ribosomes attach and make proteins • Appear to create bumps and rough areas on the membrane

41. Golgi Apparatus • Modifies, sorts, and packs proteins in sacs called vesicles • Vesicles fuse with plasma membrane • They release proteins which move through membrane to get outside of the cell

42. Vacuoles • Temporary storage for materials in the cytoplasm • Store, transport, or digest food and waste • Plant cells – 1 large vacuole • Animal cells – several little vacuoles

43. Lysosomes • Vesicles that contain digestive enzymes to digest excess or worn-out organelles and food particles • They also digest bacteria and viruses that enter the cell • They are built in the Golgi apparatus.

44. Centrioles Made of Microtubules Found near nucleus Animal Cells only Assembled right before replication Aid in cell replication

45. Mitochondria • Powerhouse • Converts organic materials into energy • ATP • Outer and inner membranes with lots of folds • Provides large surface area to break sugar molecule bonds (produce energy)

46. Chloroplasts- Plant only Capture light energy and convert it to chemical energy through photosynthesis

47. Photosynthetic Animals • 2010 - found an animal that makes proteins essential for photosynthesis • Elysiachlorotica– sea slug that looks like a giant swimming leaf • Stole chloroplasts from algae it eats • can live up to 9 months without eating • Appears green because of stolen chlorophyll • Lives - Eastern coast of the United States and Canada

48. Cilia and Flagella • Cilia- short, hair-like projections • Move back and forth like oars on a rowboat • Move substances along surface of the cell • Flagella- rather long hair-like projections • Whip-like motion • Both are composed of microtubules • Move cells through watery environment