Chapter 5 - Microbiology PDF

EXAM 2 NOTES MICROBIOLOGY CHAPTER 5 —------------------------------------------------------------------------------------------------------------------ THE HISTORY OF EUKARYOTES They first appeared 2 Billion years ago! Evidence suggests that the evolutio...

EXAM 2 NOTES MICROBIOLOGY CHAPTER 5 —------------------------------------------------------------------------------------------------------------------ THE HISTORY OF EUKARYOTES They first appeared 2 Billion years ago! Evidence suggests that the evolution of Eukaryotic happened from Prokaryotic organisms by SYMBIOSIS. - Symbiosis: prolonged association between two or more different biological species. Organelles: they originated from Prokaryotic cells trapped inside them. —------------------------------------------------------------------------------------------------------------------ UNICELLULAR, MULTICELLULAR AND COLONIAL ORGANISMS Unicellular: - Protozoa: A diverse group of unicellular Eukaryotes. They can benefit from the planet and benefit from their own arrangement. Unicellular and multicellular: - Fungi: living organisms that are eukaryotic. ALL FUNGI ARE EUKARYOTIC.(mushroom(multicellular), or yeast(unicellular) ) - Algae: they are responsible for a lot of oxygen in the water. (can be either unicellular or multicellular). Multicellular Except reproductive stages: - Helminth: Parasitic worms - Arthropods: Animal vectors of disease. —------------------------------------------------------------------------------------------------------------- STRUCTURE OF EUKARYOTIC CELLS EXTERNAL STRUCTURES: Glycocalyx ←- Capsule←- Slime layer ←- 1) Glycocalyx: surface coating that surrounds the OUTERMOST cellular membrane of cells.---> OUTSIDE THE SLIME LAYER AND THE CAPSULE. - Functions: 1) Protects cells from dehydration and nutrient loss 2) Inhibits killing by WBCs by phagocytosis 3) Formation of Biofilms 2) slime layer (underneath the glycocalyx): Loosely organized attachment, outermost layer. —> NO SHAPE= slime layer - Composed of: glycoprotein, glycolipids, exopolysaccharides. 3) capsule (underneath slime layer): it protects cells from phagocytosis, and helps cells to adhere to surfaces. —> IT IS TIGHTLY ATTACHED TO CELL. GOOD SHAPE= capsule - Composed of: Polysaccharides —----------------------------------------------------------------------------------------------------------------- BOUNDARY OF CELL Cell wall ←– Cytoplasmic membrane ←– Eukaryotic cells←– 1) Cell wall: RIGID, provides STRUCTURAL SUPPORT, AND SHAPE. —-> Cell wall determines the cell's shape. 2) Cytoplasm membrane: bilayer of PHOSPHOLIPIDS and PROTEINS - Sterols: they confer STABILITY.---> made of ringed structures, they are hydrophobic and don’t like water. —-> The cytoplasmic membrane also serves as a SELECTIVELY PERMEABLE BARRIER in TRANSPORT. 3) Eukaryotic cells: contain membrane-bound organelles that account for 60-80% of their volume. (The little organs inside the eukaryotic cells are surrounded by a membrane.) —----------------------------------------------------------------------------------------------------------------- LOCOMOTOR APPENDAGES: Flagella ←– Cilia ←- 1) Flagella: long, sheathed cylinder containing microtubules in a 9+2 arrangement. - Covered by an extension of the cell membrane. - 10X thicker than prokaryotic flagella. - Functions: rotates 360 degrees, and functions as mobility, and helps the cell move through the environment. - rotate, move, and transport. 2) Cilia: similar in overall structure to flagella, but SHORTER AND NUMEROUS. - Functions: motility, feeding, and filtering (filtering is important). - Found in: only on a single group of Protozoa, and certain animal cells. —------------------------------------------------------------------------------------------------------------ OTHER INTERNAL STRUCTURES INTERNAL STRUCTURES: Nucleus Nuclear envelope nucleolus Chromosomes Endoplasmic reticulum (ER) Golgi apparatus  vesicles Lysosomes Vacuoles Phagosomes Phagolysosome Mitochondria Cristae membrane Chloroplasts Grana Ribosomes cytoskeleton 1) Nucleus: GENETIC CENTER OF CELL. repository of DNA, and synthesis of RNA.---> Most prominent organelle in eukaryotic cells. - Composed of: a double membrane and has pores inside. ←– Nuclear envelope: composed of TWO PARALLEL MEMBRANES separated by NARROW space and is perforated with pores. —--> Double layer that encloses the nucleus (protects nucleus). —> Contains chromosomes ←— Nucleolus: DARK AREA of rRNA synthesis and ribosome assembly. (it is inside the nucleus). —------------------------------------------------------------------------------------------------------------- 2) Endoplasmic Reticulum (ER): Transport of material and lipid synthesis. - THERE ARE 2 TYPES OF ER: 1) Rough endoplasmic reticulum (RER): originates from the outer membrane of the nuclear envelope and extends in a continuous network through cytoplasm. —-> IT IS ROUGH DUE TO RIBOSOMES The proteins are SYNTHESIZED on the ribosomes and shunted into the ER for PACKAGING AND TRANSPORT.---> It is the first step in the secretory pathway!! 2) Smooth endoplasmic reticulum (SER): Closed tubular network WITHOUT RIBOSOMES. ←- - Function: nutrient processing, synthesis and storage of lipids. —-------------------------------------------------------------------------------------------------------------- 3) Golgi apparatus: STORES and PACKAGES protein PRIOR to secretion. - Consists of: Stack of FLATTENED SACS CALLED CISTERNAE. —-------------------------------------------------------------------------------------------------------------  SYNTHESIS AND TRANSPORT MACHINE ORDER: Nucleus—> RER—> Golgi—> Vesicles—> Secretion REMEMBER: - Nucleolus: Provides ribosomes that travel to the ER. - Transport vesicles: from the ER—> CONTAINING PROTEINS that go to the Golgi apparatus for MODIFICATION and MATURATION. - Condensing vesicles: transport proteins to organelles or into secretory vesicles to be exported outside. —---------------------------------------------------------------------------------------------------------------- 4) Lysosomes: INTRACELLULAR digestion. —> Vesicles containing enzymes that originate from golgi apparatus. —> Involved in intracellular digestion for food particles, and protection against invading microbes. —---------------------------------------------------------------------------------------------------------- 5) Vacuoles: membrane bound sacs containing particles to be digested (like food), excreted or stored.---> TEMPORARY STORAGE AND TRANSPORT, DIGESTION, AND REGULATION OF OSMOTIC PRESSURE(water vacuoles). 6) Phagosomes: vacuoles (food or water) merged with lysosomes (larger structure). Phagolysosome: Phagosome merges with lysosome (digesting emergent). → As soon as a phagosome merges with lysosome IT IS CALLED A PHAGOLYSOSOME. —------------------------------------------------------------------------------------------------------------- 7) mitochondria: POWERHOUSE OF CELL ATP.---> energy production and storage. - Composition: Spherical organelle with INNER and OUTER membrane that has FOLDS called CRISTAE. Cristae membrane: hold the enzymes and electron carriers of Aerobic respiration. - Other Mitochondrial Functions: divides the cell independently. DNA and PROKARYOTIC RIBOSOMES are contained in THE SPACES AROUND THE CRISTAE, CALLED MATRIX. ( MATRIX ARE CONTAINED IN THE SPACES AROUND THE CRISTAE(FOLDS), AND MATRIX CONTAIN PROKARYOTIC RIBOSOMES AND DNA). —------------------------------------------------------------------------------------------------------------ 8) Chloroplasts: they convert the energy of Sunlight into Chemical energy THROUGH PHOTOSYNTHESIS. - Found in: Algae and Plant cells  - The OUTER MEMBRANE covers the INNER MEMBRANE folded into sacs called THYLAKOIDS, stacked into GRANA. Grana: conducts the photosynthesis process and Thylakoids are stacked into it. (Grana is Thylakoid membrane) —> REACTION OF PHOTOSYNTHESIS OCCUR. - Grana carries PIGMENTS and are primary producers of organic nutrients for other organisms. Scattered in cytoplasm or associated with RER.---> It is LARGER THAN PROKARYOTIC RIBOSOMES. - Functions: Protein synthesis!! Provides STRUCTURE AND MOVEMENT. —> (microfilaments and microtubules form a network throughout the cytoplasm). - Functions: Organelles anchoring, movement of cytoplasm, transport, and structural support. (just like our skeleton). ←– —-------------------------------------------------------------------------------------------------------------- NUCLEAR MITOSIS Acronym: I- Picked - My- Apples- Today 1) Interphase: (Before Mitosis) - DNA replicates, also called “resting phase”. Twice as much DNA→ Cells grow, replicate its DNA, and prepare for cell division. 2) Prophase: First stage of Mitosis.--> Chromosomes condense and become visible, the nuclear envelope breaks down and the spindle fibers begin to form. 3) Metaphase: Chromosomes align along the equator and move to opposite poles of the cell.--> Chromosomes come apart moving to opposite ends. 4) Anaphase: sister chromatids separate and move to opposite poles of the cell.--> Chromosomes come apart moving to opposite ends. 5) Telophase: final stage of Mitosis. This is followed by cytokinesis where the cytoplasm divides and forms two daughter cells. the molds hold spores.--> SPORES FIND A GOOD ENVIRONMENT. —> Some present various textures of MYCELIA and an array of COLOR DIFFERENCE macroscopically due to spores. HYPHAE IS LONG AND ARRAYS COLOR DIFFERENCES DUE TO SPORES. - Yeast: Round ovoid shape, asexual reproduction. Yeast PRESENTS A CELL WALL AND LACKS LOCOMOTOR ORGANELLES. (Flagella and Cilia). It grows swelling on its surface called BUDS, which then become separate cells. YEAST IS ROUND AND LACKS LOCOMOTOR ORGANELLES. SOME FUNGI ARE DIMORPHIC AND CAN EXIST IN BOTH HYPHAL AND YEAST FORM. —------------------------------------------------------------------------------------------------------------- FUNGAL NUTRITION Hyphae - Filamentous fungi (Molds): cottonly, hairy, or velvet texture. - They have a woven intervening mass of hyphae called MYCELIUM that may be divided by CROSS WALLS called SEPTA. - Mycelium: mass of hyphae that make up the body of a fungus. 1) Vegetative hyphae: digests and absorbs nutrients. 2) Reproductive hyphae: produces spores for reproduction. Yeasts: Some form a PSEUDOHYPHAE which is a chain of yeats formed when buds remain attached in a row. —> because of its manner of formation, it is not a true hyphae like that of molds Pseudohyphae: chain of yeast when buds remain attached in a row. —--------------------------------------------------------------------------------------------------------- FUNGAL REPRODUCTION Fungus primarily reproduce through spores formed on reproductive Hyphae. 1) Asexual Formation of Spores: - Sporangiospores: Formed by successive cleavages within a saclike head called SPORANGIUM —> SPORES INITIALLY ENCLOSED, BUT THEY ARE RELEASED ONCE THE SPORANGIUM RUPTURES. (THEY ARE ENCLOSED AT FIRST, BUT ONCE THE SPORANGIUM RUPTURES, THEY ARE RELEASED.) 2) Sexual spore reproduction: formed by the fusion of two different strains and the formation of a sexual structure. - Types of sexual spores include: Zygospores, Ascospores, and Basidiospores. —-> SEXUAL SPORE AND SPORE FORMING STRUCTURES ARE ON BASIS FOR CLASSIFICATION. macroscopic and microscopic observation of asexual spore-forming structures and spores, hyphal type, colony texture and pigmentation, physiological characteristics, and genetic makeup. - Asexual spores and structures - Hyphal type - Colony texture and pigmentation - Physiological characteristics - Genetic makeup —---------------------------------------------------------------------------------------------------------------- ROLES OF FUNGI Fungi have both ADVERSE and BENEFICIAL impacts on medicine, nature, and industry. 1) Adverse impacts: Mycoses, allergies, toxin production, and destruction of crops and food storages. 2) Beneficial impacts: source of antibiotics, alcohol, organic acids, vitamins, decomposers of dead plants and animals, and used in making food and in genetic studies. —------------------------------------------------------------------------------------------------------------------  ANTIBIOTICS AND DISEASES Penicillium: one source of antibiotic to treat bacterial infections. Aspergillus: A common airborne mold that may be involved in respiratory infections and toxicity. Histoplasma: The cause of Ohio Valley Fever. Trichophyton: One cause of ringworm - common name of certain fungal skin infections. Coccidioides immitis: It is the cause of Valley fever. —---------------------------------------------------------------------------------------------------------------- THE PROTISTS 1) Algae: Eukaryotic organisms, usually unicellular and colonial, that is photosynthesis with chlorophyll. CHARACTERISTICS: Photosynthetic organisms Microscopic forms are unicellular, colonial, or filamentous. Macroscopic forms are colonial and multicellular. Contain chloroplasts with chlorophyll and pigments. Have a cell May or may not have Flagella Most are free-living in fresh and marine water Provide the basis of the good web in most aquatic habitats Produce a large proportion of atmospheric oxygen. DINOFLAGELLATES: can cause red tides and give off toxins that cause poisoning with neurological symptoms. —> UNICELLULAR PROTISTS COMPRISING TWO FLAGELLA. —----------------------------------------------------------------------------------------------------------------- 2) Protozoa: Unicellular eukaryotes that lack tissue and share similarities in cell structure, nutrition, life cycle, and biochemistry. CHARACTERISTICS: Diverse group of 65,000 species Vary in shape—> LACK A CELL WALL  Most are unicellular—> COLONIES ARE RARE Most are harmless, free-living in a moist habitat Some are animal parasites and spread by insect vectors —> are all heterotrophic (nutritions from organic carbon), LACK CHLOROPLASTS. Cytoplasm divided into ECTOPLASM AND ENDOPLASM Feed by engulfing other microbes and organic matters. - HETEROTROPHIC - Most protozoa have locomotor structures which are Flagella, Cilia, and Pseudopods. - TROPHOZOITE: which is the FEEDING STAGE. - Cyst: many enter a dormant stage during unfavorable conditions. ALL REPRODUCE ASEXUALLY THROUGH MITOSIS OR MULTIPLE FISSION, AND MANY ALSO REPRODUCE SEXUALLY THROUGH CONJUGATION. 1) Mitosis or multiple fission: Asexual reproduction 2) Conjugation: sexual reproduction —-------------------------------------------------------------------------------------------------------------- PROTOZOAN IDENTIFICATION Unique appearance of most protozoa allows EASY IDENTIFICATION to the level of Genus and often species by MICROSCOPIC MORPHOLOGY ALONE. IDENTIFICATION CLUES INCLUDE: Shape and size of cell Type, number, and distribution of Locomotor structures Presence of special organelles or cysts Number of nuclei MORE WAYS OF IDENTIFICATION: Medical specimens from fluids, feces, or vagina smeared directly onto a slide and observed with or without special strains. —--> SOME CULTIVATED ON ARTIFICIAL OR LABORATORY ANIMALS FOR FURTHER IDENTIFICATION OR STUDY. CAN INVADE LIVER, LUNGS AND SKIN. - Symptoms: gastrointestinal disturbances. —---------------------------------------------------------------------------------------------------------------- PARASITIC HELMINTHS Multicellular animals, organs for production, digestion, movement and protection. —-> They PARASITIZE HOST TISSUE and have mouthparts for attachment to or digestion of host tissue. —> Most have WELL-DEVELOPED SEX ORGANS that produce eggs and sperm. —> Fertilized eggs go through LARVAL PERIOD in or out the host body. —---------------------------------------------------------------------------------------------------------------- MAJOR GROUPS OF PARASITIC HELMINTHS 1) Flatworms: Flat, no definite boldly cavity, digestive tract a blind pouch, SIMPLE EXCRETORY AND NERVOUS SYSTEM. - Cestodes (Tapeworms)  1) Trematodes (Flukes): Flat, not segmented worms with sucking mouthparts. 2) Roundworms: Round, a complete digestive tract, protective surface cuticle, spines and hooks on mouth, EXCRETORY AND NERVOUS SYSTEM POORLY DEVELOPED. —----------------------------------------------------------------------------------------------------------------- CLASSIFICATION AND IDENTIFICATION They are classified according to SHAPE, SIZE, ORGAN DEVELOPMENT, PRESENCE OF HOOKS, SUCKED, OR OTHER SPECIAL STRUCTURES made of reproduction, hosts, and appearance of eggs and larvae. —-------------------------------------------------------------------------------------------------------------- DISTRIBUTION AND IMPORTANCE OF PARASITIC WORMS Approximately 50 species PARASITIZE HUMANS. Distributed worldwide, some are restricted to certain geographic regions, and with a higher incidence in the tropics. Affects billions of humans. —-> ACQUIRED THROUGH INGESTION OF LARVAE OR EGGS IN FOOD, FROM SOIL OR WATER. SOME ARE CARRIED BY INSECT VECTORS. ←—