Section 4.3 and 4.4

1. Section 4.3 and 4.4 Objectives: 4.3 Cell Organelles and Features Describe the structure and function of the 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 the mitochondria. Describe the structure and function of the cytoskeleton. 4.4 Unique features of plant cells. List 3 structures that are present in plant cells but not present in animal cells. Compare the plasma membrane, the secondary cell wall, and the primary cell wall. Explain the role of the central vacuole. Describe the role of plastids in the life of a plant. Identify features that distinguish prokaryotes, eukaryotes, plant cells and animal cells.

2. Representative Animal Cell

3. Representative Plant Cell

4. Organelles Cellular machinery Two general kinds Derived from membranes Bacteria-like organelles

5. Bacteria-Like Organelles Derived from symbiotic bacteria Ancient association Prokaryotic cells (bacteria) that were incorporated into ancient eukaryotic cells. Prokaryotic invaders were given protected place to live while eukaryotic cells had an endless supply of ATP for energy. E Endosymbiotic theory Evolution of modern cells from cells & symbiotic bacteria Mitochondria and chloroplast Release and store energy

6. Plasma Membrane Contains cell contents Double layer of phospholipids & proteins Functions- Allows certain materials to enter and leave; Separates internal metabolic reactions from external environment; allows cells to excrete waste; and allows cells to interact with their environment.

7. Phospholipids Phospolipid Bilayer Makes cell selectively permeable. Polar Hydrophylic head Hydrophobic tail Between tails of layers Sterols (cholesterol) Make membrane firm Prevent membrane from freezing at low temps.

8. Movement Across the Plasma Membrane A few molecules move freely Water, Carbon dioxide, Ammonia, Oxygen Carrier proteins transport some molecules Proteins embedded in lipid bilayer Fluid mosaic model � describes fluid nature of a lipid bilayer with proteins

9. Membrane Proteins Aka Integral proteins Types: 1. Channels or transport proteins Move molecules across the cell membrane. Extend across cell membrane. 2. Receptor proteins Recognize certain chemicals and bind to them Extend across cell membrane * Proteins that extend across the membrane can detect environmental signals and transmit them to the inside of the cell.

10. Membrane Proteins 3. Cell Surface Markers Glycoprotein Identify cell type 4. Enzymes Not a integral protein; not embedded. Catalyze production of substances Lie on only one side. * The Fluid Mosaic Model is the name given to the cell membrane. The phospholipid bilayer behaves more like a fluid than a solid. * Open your books to p. 78 and draw and label Figure 4-11 in your notes.

11. Membranous Organelles Functional components within cytoplasm Bound by membranes

12. Nucleus Control center of cell Has nucleoplasm Double membrane Contains DNA in the form of: Chromosomes-when dividing. Chromatin- threadlike; when not dividing. Nucleolus Transcription of DNA into RNA takes place here.

13. Nuclear Envelope Double membrane 2 phospholipid bilayers Has nucleopores Separates nucleus from rest of cell Allows RNA to leave and other materials to enter.

14. Nucleolus Inside nucleus Most cells have 2 or more Directs synthesis of RNA Forms ribosomes

15. Mitochondria Have their own DNA Can only be produced be pre-existing mitochondria. Bound by double membrane Break down fuel molecules (cellular respiration) Glucose Fatty acids Release energy ATP

16. Mitochondria Structure Inner and outer phospholipid layer Inner membrane has several folds called cristae Contain proteins to carry out energy harvesting reactions. Highly active cells (muscles) have hundreds of mitochondria. Draw and label the mitochondria- figure 4.13 on p.80. Label inner and outer membrane, cristae in your notes.

17. Endoplasmic Reticulum Network of interconnected membranous sacs. Helps move substances within cells Intracellular highway Amount depends on cell function. Two types Rough endoplasmic reticulum Smooth endoplasmic reticulum They are interconnected to each other.

18. Rough Endoplasmic Reticulum Ribosomes attached to surface Manufacture proteins and phospholipids. Abundant in cells that produce a lot of proteins. Digestive glands and antibody producing cells.

19. Smooth Endoplasmic Reticulum No attached ribosomes Has enzymes that help build molecules Carbohydrates Lipids such as cholesterol Function is dependent on cell Ovaries and testes produce estrogen and testosterone Heart and muscle cells release calcium Liver and kidney cells help to detoxify blood from drugs and poison.

20. Golgi Apparatus Flattened membranous sacs Involved in synthesis of plant cell wall Packaging & shipping station of cell

21. Golgi Apparatus Function Molecules come in vesicles from the ER. 2. Vesicles fuse with Golgi membrane 3. Molecules may be modified by Golgi 4. Molecules get pinched-off into separate vesicles 5. Vesicle leaves Golgi apparatus 6. Vesicles may combine with plasma membrane to secrete contents

23. Vesicles Small single membranous sacs. Types are defined by their contents. Types: Lysosomes Contain digestive enzymes to break down large molecules. Break down glycogen in the liver into glucose Functions Aid in cell renewal Break down old cell parts called autolysis Digests invaders Peroxisomes Abundant in kidney and liver cells Break down and help detoxify drugs and alcohol. Break down fatty acids for the mitochondria to use as an energy source.

24. Vesicles cont. Glyoxsomes Seeds of some plants Break down stored fats for developing seed embryo Endosomes Engulf material by surrounding it with plasma membrane. Later lysosomes will destroy the material.

25. Protein Synthesis Involves vesicles Steps: Proteins are assembled by ribosomes on the RER. Vesicles carry proteins from RER to golgi apparatus (GA). Proteins are modified in GA and enter new vesicles. Some vesicles are released outside the cell. Some vesicles become lysosomes or other types.

26. Cytoplasm Viscous fluid containing organelles components of cytoplasm Interconnected filaments & fibers Fluid = cytosol Organelles (not nucleus) storage substances

27. Cytoskeleton Filaments & fibers that criss cross the cytosol. Made of 3 fiber types Microfilaments Microtubules Intermediate filaments 3 functions: mechanical support anchor organelles help move substances See Chart p. 84

29. Cilia & Flagella Hair like Provide motility Cilia Short Used to move substances outside human cells Numerous Flagella Whip-like extensions Found on sperm cells Basal bodies are the base and organize and develop flagella and cilia.

30. Cilia & Flagella Structure Bundles of microtubules With plasma membrane

31. Centrioles In cytoplasm near nuclear envelope. Pairs of microtubular structures Play a role in cell division Only in animal cells

32. Plant Cells Why are plant cells different? Lifestyle Structures Cell wall Vacuoles Plastids

33. Representative Plant Cell

34. Cell Walls Found in plants, fungi, & many protists Surrounds plasma membrane Contains cellulose (plants) Contains chitin (fungi) Has a Primary cell wall Secondary cell wall

35. Primary cell wall Made of cellulose Enzymes travel along cell membrane Only in one direction Secondary cell wall Only in some plants Secreted between cell membrane and primary cell wall. Very rigid and strong Cannot expand

36. Vacuoles Membrane bound storage sacs Types: Central Vacuole stores water Can be 90% of volume When water available, vacuole expands and plant stands upright. When water is not, vacuole shrinks and plant wilts Other vacuoles store Toxins Poisons Pigments More common in plants than animals

37. Plastids Surrounded by double membrane Contain own DNA Types Chloroplasts Chromoplasts Leuocoplasts

38. Chloroplasts Derived form photosynthetic bacteria Solar energy capturing organelle Make carbohydrates from carbon dioxide and water Structure Contain membranous sacs called thylakoids Thylakoids contain pigment chlorophyll Chlorophyll captures and absorbs light

39. Structure of Chloroplast

40. Other Plastids Chromoplasts Pigments that may or may not participate in photosynthesis Carotene in carrot cells Leucoplasts No pigment, clear Found in roots and non-photosynthetic plant parts. Storage of bulk materials. Type depends on material stored- starch is called an amyoplasts.

41. Review of Eukaryotic Cells

42. Review of Eukaryotic Cells