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Microbiology
A deck of flashcards for Undergraduate Study of Biology.
Question | Answer |
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Metabolism in living organisms | Catabolism and Anabolism. |
Catabolism | Conversion of energy into biologically useful forms through catabolic reactions; the breakdown of complex molecules in living organisms to form simpler ones, together with the release of energy; destructive metabolism. |
Anabolism | The process by which the body utilizes the energy released by catabolism to synthesize complex molecules. These complex molecules are then utilized to form cellular structures that are formed from small and simple precursors that act as building blocks. |
What are the 4 major nutritional types among prokaryotes? | Photoautotrophs, Chemoautotrophs, Photoheterotrophs and Chemoheterotrophs. |
Photoautotrophs | Organisms that carry out photosynthesis. Using energy from sunlight, carbon dioxide and water are converted into organic materials to be used in cellular functions such as biosynthesis and respiration. All photosynthetic prokaryotes are cyanobacteria. |
Chemoautotrophs | Also known as chemolithotrophs; organisms which require only CO2 as a carbon source and obtain energy by oxidizing inorganic compounds such as H2S & NH3 rather than sunlight. |
Photoheterotrophs | Organisms that contains bacteriochlorophyll and use light to generate ATP, however they do not use CO2 as their carbon source and uses fatty acids, alcohols or other carbohydrates instead. |
Chemoheterotrophs | Organisms that much obtain organic molecules for energy and as a source of carbon. Has two sub-groups: Saprobes and Parasites. |
Autotrophs | An organism that is able to produce its own food. |
What structure in Photoautotrophs help to carry out photosynthesis? | Bacteriochlorophyll. |
Chemotrophs | Organisms that obtain energy by the oxidation of electron donors in their environments. These molecules can be organic or inorganic. The chemotroph designation is in contrast to phototrophs, which utilize solar energy. |
Saprobes | Organisms that are decomposers which absorbs nutrients from dead organic matter. |
Parasites | Organisms that absorbs nutrients from body fluids of living hosts. |
Obligate aerobes | Prokaryotes that use O2 for cellular respiration. |
Facultative anaerobes | Prokaryotes that use O2 when present, but undergoes fermentation in the absence of O2. |
Obligate anaerobes | Prokaryotes that are poisoned by oxygen. (Some species live exclusively by fementation while others use inorganic molecules other than O2 as electron acceptors during anaerobic respiration.) |
Respiration | A process where cells obtain energy by the oxidation of organic molecules. |
Aerobic respiration | The most efficient way to extract energy from glucose through Glycolysis, Kreb's cycle and Oxidative phosphorylation (ETC). |
What are the 4 major glycolytic pathways found in different bacteria? | Embden-Meyerhoff-Parnas pathway, Hexose monophosphate pathway, Entner-Doudoroff pathway and Phosphoketolase pathway. |
Anaerobic respiration | A process of respiration which includes glycolysis and fermentation where O2 is not required and no additional ATP are made from pyruvate. |
What are the 5 kingdoms of classification of living organisms? | Animalia (animals). Plantae (the plants), Protista (Single-celled eukaryotes). Fungi and Monera (the prokaryotes). |
Who is the father of taxonomy? | Carolus Linnaeus (1707-1778). |
Binominal Nomenclature | The system of nomenclature in which two terms are used to denote a species of living organism, the first one indicating the genus and the second the specific epithet. |
Species | Defined by the morphological species concept or biological species concept. |
Morphological species concept | Species being based on morphology which suggests any phenotypic trait that are similar between individuals woiuld mean they are of the same species. However, it is flawed. |
Biological species concept | Defines species in terms of interbreeding: Species are groups of interbreeding natural populations that are reproductively isolated from other such groups. |
Similarities between Prokaryotes and Eukaryotes | They both perform the same basic functions, contains a plasma membrane that controls regulation, contains cytoplasms and ribosomes to synthesis proteins. They both contain DNA to give the general instructions to the cell. |
Differences between Prokaryotes and Eukaryotes | Prokaryotes are much smaller and less complex. They also do not have a true nucleus and contain circular DNA that is found in the cytoplasm with no other organelles other than ribosomes. |
Cell division in Prokaryotes | Binary fission |
Cell division in Eukaryotes | Mitosis or Meiosis |
Endospores | A resistant cell formed by some bacteria which contains one chromosome copy surrounded by a thick wall. |
Classification of Bacteria | Based by their ability to uptake certain stains (Gram positive & Gram negative) and on oxygen requirement (Aerobic & Anaerobic). |
Shape and size of Bacteria for classification | Cocci, Spiral and Bacilli. |
Cocci | Spherical or oval shaped bacteria. Average size 0.5-1 micrometer. May be either gram positive or negative. |
Spiral | Spiral shaped bacteria. Average size 1-100 micrometer. Only gram negative. |
Bacilli | Cylindrical or rod-shaped bacteria. Average size: 1.0-4 micrometer. Mostly gram positive, but some are gram negative. |
Domain Archaea | Three main groups: Methanogens, Extreme halophiles and Extreme thermophiles. |
Proteobacteria | A group of bacteria containing 3 subgroups: Purple bacteria, Chemoautotrophic proteobacteria and Chemoheterotropic proteobacteria. |
Gram-positive eubacteria | Eubacteria that are able to take up crystal violet color. Mostly chemoheterotophs, while some are photoautotrophs. |
Cyanobacteria | Photoautotrophs containing bacteriochlorophyll. |
Spirochetes | Helical thin structures that are sometimes very long. Chemoheterotrophs which include both free-living species and pathogens. |
Chlamydiae | Obligate intracellular parasites of animals which obtains all their ATP from host cells. |
Structures of a bacterium | The cell envelope, cytoplasmic membrane and cell wall. |
Cell envelope | Also known as a capsule. It is a protective layer present in some bacteria which are made up of polysaccharides (complex carbohydrates) which prevents dehydration and protects from phagocytosis by predators. |
Pili | Hair like projections from outer cell surface which helps in adhesion to the host's tissue. |
Bacterial stains | Cationic dyes, Anionic dyes, Simple stain, differential stains, gram stain. |
Cationic dyes | These are positively charged and binds to negatively charged cellular components such as nucleic acids (DNA and RNA) and acidic polysaccharides. |
Anionic dyes | These are negatively charged and combine with positively charged cellular components such as proteins. |
Simple stain | A solution consisting of a single dye, which helps in quick identification of bacterial stains based on their morphology. |
Differential strains | Stains that are used to differentiate cellular components. They are used to examine structural differences between bacterial groups or to provide contrast to different structures within the same organism. |
Gram stain | Uses 3 different stains; Crystal violet, Gram's iodine and safranin. |
Differences between Gram positive and Gram negative bacteria | Cell wall composition; Gram positive: contains thick layer of peptidoglycan in their cell. Gram negative: thin layer of peptidoglycan and high lipid content. |
Recombinant DNA (Plasmid + gene) | With the use of restriction enzymes, the gene of interest may be added into a plasmid (cloning vector) through DNA ligation. |
Competent cell | Bacterial that are able to uptake plasmid (foreign DNA) |
Viruses | Latin for poison; an independant living organism and does not adhere to the strict definition of life. They cannot reproduce unless they are able to infect a living cell through their metabolic pathways. They are non-cellular. |
Virus morphology | Helical (where capsomeres wrap around the nucleic acid to produce a helix), and Icosahedral (repeating capsomeres formed with 20 triangular faces). |
Obligate intracellular parasite (Virus) | Host specific and for human viruses they are specific for a particular tissue. |
Transmission of viruses | Respiratory, Faecal-oral, Blood-borne, Sexual and Animal/insect vectors. |
Lytic cycle | Virus attaches to the cell, Penetrates/injection of viral DNA or RA, Replication/Biosynthesis of new viral proteins and nucleic acids, Assembly (maturation) of the new viruses and release of new viruses (Cell lyses). |
Lysogenic cycle | Phage DNA injected into host cell, viral DNA joins host DNA forming a prophage. When an activation signal occurs, the phage DNA starts replicating. Viral DNA may stay inactive for long periods of time and is replicated during binary fission. |
Latent viruses | Viruses that has the ability to become dormant. |
Characteristics of Retroviruses | Viruses containing RNA, not DNA, contains the enzyme reverse Transcriptase. |
Viroids | Small, circular RNA molecules without a protein coat which depends on host's cellular RNA polymerase to replicate. |
Prions | Infectious proteins; normal body proteins that get converted into an alternate configuration by contact with other prion proteins without any nucleic acid. |
Vaccines | An attenuated (weakened) virus is a weakened less vigorous virus capable of stimulating an immune response to create immunity. |
Microbial growth | Lag phase, Exponential phase, stationary phase and death phase. |
Uses of industrial and environment microbiology | Biotechnology, food/beverage industry, agriculture, human health, bioremediation, environment recycling. |
Bacterial growth | Division by binary fission; a form of asexual reproduction. |
Lag phase | A brief period after inoculation whereby the cells adapt to the new conditions. Bacteria are producing the enzymes necessary to digest the nutrients. The growth rate begins to increase towards the end of the phase. |
Logarithmic/Exponential phase | A rapid period of growth during this phase where the enzymes necessary are already developed and plenty of nutrients are present. Few waste products are produced and cell division rate is at its maximum. |
Stationary phase | The rate of growth levels off during this period where the nutrients are becoming used up, waste produced are increasing and the rate new cells are produced are equal to those of which are dying. |
Death phase | During this phase more bacteria are dying than produced because very few nutrients are left, many bacteria are poisoned by the waste produced in large numbers and thus the rate of growth is falling. |
Microbes and food industry | Probiotics, dairy products, microbial enzymes in food industry, fermented beverages, single cell proteing SCP. |
Probiotics | Live microbial feed supplements that have beneficial effects on the host by improving its intestinal microbial balance. |
Microbes and agriculture | Certain soil bacteria live symbiotically in the roots of legumes (N2 fixing bacteria) which convert inert N2 gas into amines. |