1. The Cell Chapter 4

2. Cells  Marks the boundary between the “ living and the dead ”  Structural and functional unit of an organism  Smallest structure capable of performing all of the functions necessary for life

3. What is a cell?  Why do we care? We have TRILLIONS of them!! (@65) Every organism is composed of one or more cells Basic unit of structure and function in organisms All come from pre-existing cells Cell Theory

4. All cells…….  Have an outer plasma membrane  Contain DNA Enclosed within the cell somewhere  Contain cytoplasm

5. Plasma Membrane and Cytoplasm  All cells surrounded by a plasma membrane Phospholipid bilayer  material inside a cell is the cytoplasm Everything between the plasma membrane and the region of DNA Gives cells their shape Assist in movement of cell and organelles

6. Microscopes  Compound light microscope Multiple lenses increase magnifying power

7. Two basic kinds of cells  Prokaryotic Nothing separates the DNA from internal cell parts  Eukaryotic Contain organelle sacs Nucleus – contains the DNA

9. Eukaryotic Cells

10. Examples of Eukaryotic Cells:  Animal  Plant  Fungi  Protozoa

11. Cell Walls  Plant cells Permeable Protective In addition to a plasma membrane

12. Organelles  Organelles act as their own separate “ organs ” They physically isolate chemical reactions inside cells Animals and plants will differ in their organelles

15. Nucleus  Encloses the DNA of a eukaryotic cell  Contains chromosomes  Functions: Prevents DNA from getting entangled with structures in the cytoplasm Outer membranes act as a boundary

16. Components of the nucleus  Nuclear pores  Nuclear envelope  Nucleolus  Nucleoplasm  DNA Chromosomes Chromatin

17. Nuclear envelope  Double-membrane system composed of lipid bilayer (with pores)  Bilayers surround the fluid part of nucleus (nucleoplasm)  Continuous with the endoplasmic reticulum

18. Nucleolus  Dense mass located within the nucleus  Produces ribosomes

19. Ribosomes  Site of protein synthesis  Occurs in the cytoplasm  Attached to the endoplasmic reticulum  Differ between prokaryotes and eukaryotes Why is this important from a health aspect?

20. Endomembrane System  Helps modify proteins into final form Lipids are assembled  Compartmentalizes the cell  Main components: 1. Nuclear envelope 2. Endoplasmic reticulum (ER) 3. Golgi body 4. Various vesicles (transport)

21. 1. Nuclear envelope  Merges with the membrane of the ER  Consists of membranous channels and saccules

22. 2. Endoplasmic Reticulum  Channel that snakes through the cytoplasm  Lipids assembled and polypeptide chains modified into final proteins  Can be rough or smooth Dependant on the attachments of ribosomes Rough ER  Processing and modification of proteins Smooth ER  Synthesizes phospholipids

23. 3. Golgi Body (Apparatus)  Series of flattened sacs  Collects, sorts, packages, and distributes materials such as proteins and lipids  Contain enzymes that put the finishing touches on proteins and lipids

24. 4. Vesicles  Enzymes from golgi apparatus sort and package the molecules into vesicles Tiny sac that moves through cytoplasm Function in transport, storage, or digestion of substances Two main types:  Lysosomes  Peroxisomes

25. Lysosome  A lysosome is a membrane-enclosed sac contains digestive enzymes to break down:  Macromolecules  damaged organelles

26. Put it all together……

27. Energy-Related Organelles  organelles specialize in converting energy to a form that can be used by the cell Requires solar energy Dissipates as heat  Chloroplasts Use solar energy to synthesize carbohydrates Carbohydrates then broken down in the…..  Mitochondria Produce ATP molecules

28. Energy-Related Organelles  Photosynthesis  Cellular Respiration The chemical energy of carbohydrates is converted at ATP

29. Cytoskeleton: Cilia and Flagella - Movement  Hairlike projections  Help in the movement of cells  Some examples….  Why would we need them?

31. Vacuoles  Membranous sacs contractile vacuoles of protists central vacuoles of plants

32. Prokaryotes Archae Bacteria

33. Prokaryotic Cells  Cell Wall  Capsule  Flagellum  Plasma membrane  Nucleoid  Plasmids  Ribosomes