2.  Prokaryotes  Do not have membrane surrounding their DNA  lack a nucleus  Lack various internal structures bound with phospholipid membranes  Are small, ~1.0 µm in diameter  Have a simple structure  Composed of bacteria and archaea

3.  Eukaryotes  Have membrane surrounding their DNA  Have a nucleus  Have internal membrane-bound organelles  Are larger, 10-100 µm in diameter  Have more complex structure  Composed of algae, protozoa, fungi, animals, and plants

4. [INSERT FIGURE 3.1]

6.  Structure  Referred to as phospholipid bilayer; composed of lipids and associated proteins  Approximately half composed of proteins that act as recognition proteins, enzymes, receptors, carriers, or channels Integral proteins Peripheral proteins Glycoproteins  Fluid mosaic model describes current understanding of membrane structure

7. Membranes contain a hydrophilic and hydrophobic side Composed of many different types of proteins Proteins in the lipid bilayer move freely within the membrane

8. Thin pliable lipid and protein envelope that defines a cell. Phospholipid bilayer Functions:  Regulates nutrient and water intake  Regulates waste removal  Site of prokaryotic respiration  Site of prokaryotic flagella attachment  Involved in the distribution of genetic material during binary fission

9.  Function  Energy storage  Harvest light energy in photosynthetic prokaryotes  Selectively permeable  Naturally impermeable to most substances  Proteins allow substances to cross membrane Occurs by passive or active processes  Maintain concentration and electrical gradient Chemicals concentrated on one side of the membrane or the other Voltage exists across the membrane

12.  Glycocalyces  Gelatinous, sticky substance surrounding the outside of the cell  Composed of polysaccharides, polypeptides, or both

13.  Types of Glycocalyces  Capsule Composed of organized repeating units of organic chemicals Firmly attached to cell surface Protects cells from drying out May prevent bacteria from being recognized and destroyed by host

14. Polysaccharides or polypeptides in composition. Surround the cell wall in some bacteria. Function:  Protection from phagocytosis  Osmotic barrier  Reservoir for nutrients  Virulence factor

16. Consist of polysaccharide fibers that extend form the bacterial surface Functions:  Protection  Attachment  Associated with biofilms

17.  Types of Glycocalyces  Slime layer Loosely attached to cell surface Water soluble Protects cells from drying out Sticky layer that allows prokaryotes to attach to surfaces

18. Flagella Axial Filaments Pili (Fimbriae)

19. Flagella Structures of locomotion Originate in the plasma membrane In bacteria rotate like a propellar Many different arrangements

20.  Flagella  Are responsible for movement  Have long structures that extend beyond cell surface  Are not present on all prokaryotes

21.  Flagella  Structure  Composed of filament, hook, and basal body  Flagellin protein (filament) deposited in a helix at the lengthening tip  Base of filament inserts into hook  Basal body anchors filament and hook to cell wall by a rod and a series of either two or four rings of integral proteins  Filament capable of rotating 360º

22. Arrangements of Flagella A. Monotrichous B. Lophotrichous C. Amphitrichous D. Peritrichous

23. Axial filament (endoflagella) Originates in the cell membrane and transverses the length of the cell in the periplasmic space. As the endoflagella rotate to move the cell the characteristic shape is formed. Endoflagella are associated with spirochetes.

24. Endoflagellum is also know as an axial filament. Attached to the plasma embrane and transverses the entire cell. Responsible for the spirochete morphology.

25.  Flagella  Function Rotation propels bacterium through environment Rotation reversible, can be clockwise or counterclockwise Bacteria move in response to stimuli (taxis) Runs Tumbles

26.  Fimbriae and Pili  Rod-like proteinaceous extensions

27. Fimbriae Hollow tubes that protrude from some bacteria Compose of protein

28. Fimbriae Sticky, bristlelike projections Used by bacteria to adhere to one another, to hosts, and to substances in environment Shorter than flagella May be hundreds per cell Serve an important function in biofilms Virulence factor

29.  Pili  Tubules composed of pilin  Also known as conjugation pili  Longer than fimbriae but shorter than flagella  Bacteria typically only have one or two per cell  Mediate the transfer of DNA from one cell to another (conjugation)

30. Bacterial Conjugation Transfer of plasmid DNA from a donor to a recipient. Process strengthens the bacterial cell and alows for survival in a competitive environment.

31. 1. poly-Beta-hydroxybutyric acid - stores lipids for use in plasma membrane 2. glycogen - stores starch like polymer of sugar for energy production 3. Polyphosphate granules (metachromatic granules) - storage for phosphates for plasma membrane and the formation of ATP from ADP. 4. Sulfur granules - stores sulfur which is necessary for the metabolic reactions in biosynthesis.

32. Mesosomes - invagination of the plasma membrane that increases the surfaces area of the plasma membrane during binary fission. The mesosome also serves as a site for the attachment and distribution of genetic material during binary fission.

33. In prokaryotic cell division, called binary fission. A diagram of the attachment of bacterial chromosomes, indicating the possible role of the mesosome (an inward fold of the cell membrane) in ensuring the distribution of the "chromosomes" in a dividing cell. Upon attachment to the plasma membrane, the DNA replicates and reattaches at separate points. Continued growth of the cell gradually separates the chromosomes and allocates chromosome copies to the two daughter cells.

34. 6. gas vacuoles - storage of metabolic gases such as methane or hydrogen gas. The gas vacuoles help in the buoyancy of the cell and aids in it motility. 7. ribosomes - responsible for the synthesis of proteins. 8. nucleoid material - the genetic material of bacteria, which usually is balled up in the cell. During binary fission the nucleoid material unravels within the cell in order to be copied and distributed to the daughter cells. 9. Plasmid - small fragments of self-replicating extrachromosomal DNA that codes for the resistance to antibiotics or for the productions of a specific metabolite, i.e. toxins, pigments. These plasmids may be transferred from one bacterial cell to another by the F-pili.

36. These plasmids may be transferred from one bacterial cell to another by the F-pili.

38. 10. Endospores - a survival mechanism of certain genera of bacteria such as Clostridium and Bacillus. The endospores are composed of a complex of dipicolinc acid and calcium and the function of the endospore is to protect the bacterial chromosome. The endospores are very resistant to heat, desiccation, freezing, and other physical properties such as pesticides, antibiotics, dyes, and acids.

39. The endospores may remain dormant for many years until the environment becomes suitable to sustain the life of the bacteria. The endospore will then germinate to form an exact copy of the parent cell that produced it.

42.  Fungi, algae, plants, and some protozoa have cell walls but no glycocalyx  Composed of various polysaccharides  Cellulose found in plant cell walls  Fungal cell walls composed of cellulose, chitin, and/or glucomannan  Algal cell walls composed of cellulose, proteins, agar, carrageenan, silicates, algin, calcium carbonate, or a combination of these

43. Three different types of cell walls and their compositions: Fungal cell walls are composed of cellulose and/or chitin. Plant cell walls are composed of cellulose. Algal cell walls are composed of cellulose, silicon, and calcium carbonate.

44. Consist of a lipid bilayer and associated proteins. The Plasma Membrane of Eukaryotic cells resembles and functions in the same manner as the prokaryotic plasma membrane with the following exceptions; Contains high levels of sterols such as cholesterol. No respiratory enzymes are located in the eukaryotic plasma membrane. Respiration occurs in the mitochondria.

45.  Glycocalyces  Never as organized as prokaryotic capsules  Help anchor animal cells to each other  Strengthen cell surface  Provide protection against dehydration  Function in cell-to-cell recognition and communication

46. Flagella There are several different arrangements of flagella in eucaryotes. This diagram represents a biflagellated eukaryotic cell. One of the flagella aids in movement laterally and the other aids in up and down movement. The eukaryotic flagella move like a whip. See Flagellar handout.

47.  Flagella  Function Do not rotate, but undulate rhythmically

48. Cilia Similar to flagella both structurally and functionally but are much shorter and more numerous. Cilia are found peritrichously to the cell. Move in an undulating manner and motility by those organisms with cilia is much more rapid than those with flagella.

50.  Membranous Organelles  Nucleus  Often largest organelle in cell  Contains most of the cell’s DNA  Semi-liquid portion called nucleoplasm  One or more nucleoli present in nucleoplasm; RNA synthesized in nucleoli  Nucleoplasm contains chromatin – masses of DNA associated with histones  Surrounded by nuclear envelope – double membrane composed of two phospholipid bilayers  Nuclear envelope contains nuclear pores

51. Nucleus - double membraned organelle that houses the genetic material of cell. Nuclear membrane contains numerous pores through which proteins and RNA can move.

52.  Membranous Organelles  Endoplasmic reticulum  Netlike arrangement of flattened, hollow tubules continuous with nuclear envelope  Functions as transport system  Two forms  Smooth endoplasmic reticulum (SER) – plays role in lipid synthesis  Rough endoplasmic reticulum (RER) – ribosomes attached to its outer surface; transports proteins produced by ribosomes

53. Endoplasmic reticulum - network of cytoplasmic membranes where lipids and proteins are produced. Smooth ER - synthesis of lipids Rough ER - associated with ribosomes and is responsible for the synthesis of proteins..

54.  Membranous Organelles  Golgi body  Receives, processes, and packages large molecules for export from cell  Packages molecules in secretory vesicles that fuse with cytoplasmic membrane  Composed of flattened hollow sacs surrounded by phospholipid bilayer  Not in all eukaryotic cells

55. Golgi apparatus (dictyosome) is associated with the ER. It modifies and packages the lipids and proteins manufactured by the ER and places them in vesicles for cellular use.

56.  Membranous Organelles  Lysosomes, peroxisomes,vacuoles, and vesicles Store and transfer chemicals within cells May store nutrients in cell Lysosomes contain catabolic enzymes Peroxisomes contain enzymes that degrade poisonous wastes

57.  Membranous Organelles  Mitochondria Have two membranes composed of phospholipid bilayer Produce most of cell’s ATP Interior matrix contains 70S ribosomes and circular molecule of DNA

58. mitochondria - involved in the production of chemical energy in the form of ATP. Consist of convoluted inner membrane and outer membrane. Invaginations are called cristae and contain enzymes used to synthesis ATP. All respiratory enzymes are located in the inner membrane of the mitochondria.

59.  Membranous Organelles  Chloroplasts Light-harvesting structures found in photosynthetic eukaryotes Have two phospholipid bilayer membranes and DNA Have 70S ribosomes

60.  Endosymbiotic Theory  Eukaryotes formed from union of small aerobic prokaryotes with larger anaerobic prokaryotes  smaller prokaryotes became internal parasites Parasites lost ability to exist independently; retained portion of DNA, ribosomes, and cytoplasmic membranes Larger cell became dependent on parasites for aerobic ATP production Aerobic prokaryotes evolved into mitochondria Similar scenario for origin of chloroplasts  Not universally accepted

61. [INSERT TABLE 3.5]

62. [INSERT TABLE 3.4]

63. [INSERT TABLE 3.3]