Microbiology Flashcards

Question

Photoautotrophs (source of energy, source of carbon and examples)

Answer 1

Light CO2 Purple sulfur and green sulfur bacteria

Answer 2

Light Organic carbon Purple non sulfur bacteria

Answer 3

Inorganic chemicals CO2 Nitrobacter, Nitrosomanas, Thiobacillus thiooxidans

Answer 4

Organic chemicals Organic carbon Most bacteria

Answer 5

Require O2 for their survival Generate energy by oxidative phosphorylation Acetobacter sp.

Answer 6

Cannot survive in the presence of O2 Generate energy by fermentation Clostridium sp.

Answer 7

Prefer to grow in the presence of O2 producing energy by oxidative phosphorylation They can also grow in anaerobic environments using fermentation Escherichia coli

Answer 8

Can grow only in O2 concentrations lower than those in air Lactobacilus sp

Answer 9

Mostly undergoes asexual reproduction - Binary fission, fragmentation or budding Performs conjugation as a sexual method

Answer 10

Majority of unicellular forms stay together by copious secretion of mucilage by daughter cells. In colonial forms cells remain attached by walls or held in a common gelatinous matrix forming a colony of cells. Types - spherical, cubical, square or irregular shape.

Answer 11

Free living - Nostoc sp. Symbiotic - Anabaena-Azolla sp

Answer 12

Nitrogen fixation takes place in special cells called heterocyst. Nitrogen fixation is catalysed by the enzyme nitrogenase. Nitrogenase is sensitive to O2. Heterocyst carry thick cell wall to protect nitrogenase from O2 Akinete is a thick walled resting spore with stored food. Akinete is resistant to drought and high temperatures. They are able to survive during unfavourable environmental conditions although vegetative cells dries out.

Answer 13

Reproduces only by asexual methods Single unicellular forms and colonial non-filamentous types by simple cell division Colonial unicellular and colonial filamentous by fragmentation

Answer 14

Saprophytic (decomposers) Parasitic (plant and animal pathogens) Mutualistic (lichens and mycorrhizae)

Answer 15

Unicellular fungi reproduce asexually by fission or budding Filamentous fungi asexually or sexually by producing spores

Answer 16

Occurring in various distinct forms

Answer 17

Photoautotrophic Heterotrophic Mixotrophic

Answer 18

Aerobic Anaerobic Facultative anaerobic

Answer 19

Reproduce sexually by gametes and asexually by fission

Answer 20

Mollicutes are prokaryotes included in the domain Bacteria Mycoplasma and phytoplasma are considered unique due to the absence of cell walls

Answer 21

Pleomorphic Smallest prokaryotic group of microorganisms invisible under the light microscope Do not contain flagella Almost all mycoplasma are parasites of humans and animals Reproduce by budding and binary fission and do not posses spores Requires high amount of growth factors Aerobes or facultative anaerobes

Answer 22

Similar in size to mycoplasma Only can be seen under the electron microscope Phytoplasma only infect plants and are generally present in the phloem sap Cannot grow in artificial media Transmitted mostly by leafhoppers Reproduce in both leafhoppers as well as plant body Reproduce by binary fission and budding Posses aerobic or facultative anaerobic mode of respiration

Answer 23

Do not show any cellular organisation Not considered as living organisms Can only multiply with a host cell (obligate parasites)

Answer 24

Composed of a central core of nucleic acid and surrounded by a protein coat called the capsid which is made up of a fixed number of protein subunits called capsomeres May have either DNA or RNA as their genetic material Depends on the host cell's protein synthesis machinery Consists of reverse transcriptase enzymes for reverse transcribing RNA into DNA

Answer 25

Helical viruses- Long rigid or flexible rods e.g: Rabies virus Icosahedron - Icosahedron symmetry e.g: Aden virus Complex - Exhibits more than one form of symmetry with additional structures e.g: Bacteriophage Enveloped viruses - Roughly spherical. Capsid covered by envelopes e.g: Herpes simplex virus

Answer 26

Are typical group of viruses that are capable of infecting bacteria

Answer 27

Lytic cycle Lysogenic cycle

Answer 28

Lytic cycle involves with the lysis of the host cell whereas the lysogenic cycle allows viral DNA incorporating into host DNA and multiply without causing lysis of the host cell

Answer 29

Attachment Penetration Biosynthesis Maturation Release

Answer 30

Consist only of short piece of RNA with no protective layer such as a protein coat Can only multiply within a host cell Do not contain any gene and only carry signals for their multiplication Viroids infect plants, but no other life forms unto date

Answer 31

Are proteinaceous infectious particles. Smaller this virus Lack nucleic acid but can replicate with the help of host's gene that encodes the prion protein Found as disease causing agents in some birds and mammals All these diseases are neurological diseases

Answer 32

All are neurological Transmissible Spongiform Encephalopathies (TSEs) - Large vacuoles develop in the brain giving spongy like appearance Mad cow disease (emerged in cattle) Creutzfeldt-Jakob disease (CJD) is one of the human diseases caused by prions

Answer 33

Process of removal or destruction of all forms of microbial life including endospores 2 types as physical and chemical

Answer 34

Moist heat sterilisation (done by denaturing proteins under high temperature and pressure) Dry heat sterilisation - direct flaming, Incineration, Hot-air sterilisation Pasteurisation Boiling Filtration UV radiation

Answer 35

Moist heat is used to sterilise culture media, heat stable reagents and laboratory equipments. E.g: autoclaving, pressure cookers

Answer 36

Dry heat is used to sterilise glassware, Petri dishes, pipettes, inoculation loops and needles and scalpels

Answer 37

High temperature short-time (HTST) - 72 C , 15 s Low temperature long time (LTLT) - 63 C, 30 min Ultra high temperature (UHT) - 140 C, less than 5 s

Answer 38

Used to sterilise heat stable liquids such as enzymes and some culture media. Pore size varies from 0.01micrometers to 0.45 micrometers

Answer 39

Does not penetrate through solid surfaces and coverings such as paper, glass and textile

Answer 40

Ethylene oxide kills microorganisms and endospores (highly penetrating) Chlorine dioxide has been used to fumigate enclosed building areas contaminated endospores of Bacillus anthracis

Answer 41

Chlorine dioxide

Answer 42

Is a material prepared for providing nutrients and anchorage which are essential for the growth of microorganisms under laboratory conditions Agar is used as a solidifying agent (agar solidifies at temperatures below 40 C). Before microbes are entered glassware and nutrient medium should be sterilised. Prior to observation microbes are stained once on the glass slide for better viewing. e.g: methylene blue, crystal violet and saffranin

Answer 43

Nutrient agar - peptones, meat extract, NaCl, agar and distilled water. Used to culture bacteria. Potato-dextrose agar (PDA) - Potatoes, glucose, agar and distilled water. Used to culture fungi.

Answer 44

Generally humans are free of microbes at birth. During the birth, newborn first gets in contact with the microbes present on the vagina of mother. Usually these are Lactobacilli Lactobacilli colonise the intestine of the new-born. These are called the normal microbiota

Answer 45

it has been estimated that their are 10*14 microbial cells for every 10*13 body cells. Most of these microbes are not harmful or even beneficial. e.g: E.coli in low concentrations in the large intestine synthesise vitamin K and B and avoid colonisation of certain disease causing agents such as Salmonella typhi. Probiotics are live microbial cultures which and alleviate diarrhoea and prevent entry of Salmonella enteric during antibiotic therapy. Most of these microbes colonise on inner surfaces of the body such as mucous membrane of nasal tract, throat, upper respiratory and intestinal and genitourinary tracts. Some are opportunistic (E.coli)

Answer 46

An organism or entity (non-living entities such as virus and prions) that is capable of causing disease.

Answer 47

Organism with within which infected pathogens live on or in and multiply.

Answer 48

The ability of a pathogen to cause disease in the host by overcoming the defence of a host

Answer 49

An organism or entity living on or in another living organism (host) and obtain nutrients and other resources from the host.

Answer 50

Having optimal growth conditions(temperature) which corresponds to the body conditions of the host. Having structures to adhere to host cells and to protect against host's defence mechanisms. e.g: capsule, pilli produce toxins Having enzymes for invasiveness such as phospholipase, lecithinase and hyaluronidase Having DNase to alter host's metabolic processes

Answer 51

Is the degree of pathogenicity of the pathogen

Answer 52

Certain genes of the pathogenic microorganisms express factors which gives them the ability to infect the host and cause diseases

Answer 53

Is the ability of the pathogens to invade tissues by overcoming host's defence mechanisms and multiply for colonising

Answer 54

Ability of microorganisms to produce biochemical substances known as toxins that disrupt the normal functions of cells. Toxins can be proteins or lipopolysaccharides which are known as biological poisons.

Answer 55

Endotoxins are lipopolysaccharides Thermo-stable toxins which are part of the microbial cell. Endotoxins gets released when the microbial cell dies and the cell walls are broken apart All endotoxins cause the same symptoms regardless of the species of pathogen which includes chills,fever,weakness, generalized aches and sometimes shock and death Endotoxins are produces only by gram-negative bacteria e.g: Lipopolysaccharides of the cell walls of Salmonella typhi

Answer 56

Produced inside bacterial cells as part of their growth and metabolism and are secreted to the surrounding after cell lysis Exotoxins are proteins (thermo-liable), majority are enzymes (inactivated by boiling). Due to the catalytic nature only a small amount will be quite harmful Commonly produced by gram-positive bacteria and few gram-negative bacteria 3 types as neurotoxins, enterotoxins and cytotoxins

Answer 57

Neurotoxins - interfere with normal transmission of nerve impulse. e.g: Clostridium tetani and Clostridium botulinum Enterotoxins - stimulates cells of the gastrointestinal tract in a abnormal way. e.g: Vibrio cholera Cytotoxins - kills host cells by enzymatic attack. e.g: Corynebacterium diphtheriae

Answer 58

Herpes virus (varicella-zoster) Skin

Answer 59

Rubella virus Skin

Answer 60

Measles virus Skin

Answer 61

Haemophilus influenza / Adenovirus Eye

Answer 62

Streptococcus pneumonia Haemophilus influenza Neisseria meningitis Nervous system

Answer 63

Clostridium tetani Nervous system

Answer 64

Rabies virus Nervous system

Answer 65

Streptococcus pyogenes Cardiovascular system

Answer 66

Mycobacterium tuberculosis Respiratory system

Answer 67

Influenza virus Respiratory system

Answer 68

Streptococcus pneumonia Respiratory system

Answer 69

Hepatitis A virus Digestive system

Answer 70

Staphylococcus aureus Digestive system

Answer 71

Vibrio Cholera Digestive system

Answer 72

Salmonella typhi Digestive system

Answer 73

Leptospira interrogans Urinary system

Answer 74

Neisseria gonorrhoea Reproductive system

Answer 75

Herpes simplex virus Reproductive system

Answer 76

Human immunodeficiency virus Immune system

Answer 77

Pleomorphic Different locomotive structures such as pseudopodia, cilia or flagella Photoautotrophs, heterotrophs or mixotrophs Aerobes, anaerobes or facultative anaerobes Symbiotic interactions with lichens Sexually by gametes or asexually by fission

Answer 78

Destroy animal cell membranes

Answer 79

Hydrolyses the lecithin component of lipid in cell membranes

Answer 80

Destroys body tissues by breaking down the hyaluronic acid which is cementing substances between cells

Answer 81

Major difference is that antiseptics can be safely directly applied to the human body. Generally formulated as liquids and their effectiveness varies with concentration, duration of exposure, temperature and presence of organic matter. Antiseptics - ethanol, isopropanol, chloroxylenol Disinfectants - phenol, hypochlorites (Na and Ca)

Answer 82

Polio virus, tuberculosis bacterium, spores of bacteria and fungi

Answer 83

Inhibition of cell wall synthesis - Penicillin Inhibition of protein synthesis - Erythromycin, Tetracycline Disrupting plasma membrane - Daptomycin Inhibition of DNA/RNA synthesis - Rifampin

Answer 84

Is a suspension of weakened pathogen or fractions of organisms that are used to induce immunity

Answer 85

Contains the live but weakened pathogen. Mimics an an actual infection and provides lifelong immunity. Booster vaccination is not needed. e.g: MMR, Chickenpox

Answer 86

Pathogen is inactivated or killed and requires booster doses. e.g: Rabies, influenza, polio and cholera

Answer 87

Contains only the antigenic fragment of the pathogen that can induce immunity in the recipient. Types as toxoid vaccines and recombinant vaccines. Subunit vaccines requires repeated booster doses. Toxoid vaccines contain the inactivated toxin derived from pathogens. e.g: Diphtheria and tetanus Recombinant vaccines are made using genetic engineering. e.g: Hepatitis-B vaccine

Answer 88

Babylonian and Sumerian civilisations used yeast to make alcohol in 6000 BC

Answer 89

Simple nutritional requirements are sufficient for their growth. Able to convert a wide range of raw materials Able to convert cheap raw materials into industrially important products Due to their high growth rate, raw materials can be converted to products within a short period of time Growth conditions can be controlled to obtain desired end products Reactions can be carried out a low temperatures, energy and pressure Gives higher yield with higher specificity

Answer 90

Microbial cells are used as end products. e.g: single cell proteins Microbial metabolic products are used as end products. e.g: primary end products - alcoholic beverages, secondary end products - antibiotics Microbial metabolic processes are used as end products. e.g: bioremediation, metal extraction and retting GM microbes are used to produce end products. e.g: commercial enzymes, vaccines and hormones

Answer 91

Microbial cells grown in large scale as food supplements and are rich in proteins. E.g: Yeast, Chlorella sp and Spirulina sp

Answer 92

Yeast oxidises simple sugars such as sucrose derived from sugarcane into ethanol and CO2.

Answer 93

1. Alcoholic fermentation - sugar is fermented by S.cerevisiae. Ethanol is subjected to acetic acid fermentation 2. acetic acid fermentation - Ethanol undergoes incomplete oxidation to produce acetic acid. Highly aerobic and involves Acetobacter sp and Gluconobacter sp

Answer 94

Lactic acid producing bacteria converts lactose sugar in milk into lactic acid. e.g: L.bulgaricus, L.lactis and S.thermophillus

Answer 95

Citric acids - sucrose fermented by Aspergillus niger

Answer 96

Some metals from ores are extracted with the help of microbes (leaching). e.g: extraction of Cu from low grade Cu ore which other extraction methods are unprofitable, Thiobacillus ferrooxidans recovers Cu from ores that contain Fe and S (about 70%), Uranium and gold can also be leached.

Answer 97

Is the process of loosening fibres from woody stems or other plant materials such as coir. Pectinases facilitate loosening.

Answer 98

Residues of pesticides such as heavy metals, insecticide DDT, herbicide 2,4-D

Answer 99

Technology that applies of living organisms to remove, degrade or detoxify pollutants. Functions - remediate soil and water contaminated with oil spills, toxic metal waste, hazardous organic wastes Decompose wastewater from food processing and chemical plants

Answer 100

Soil provides an adequate physical and chemical environment for the growth of microorganisms in terms of space and nutrients such as minerals, water, decaying organic matter and gases such as O2, CO2 and N2. Depth of soil leads to diversity between soil microbes. Top few cm hv the largest community of microbes. Majority of soil microflora includes bacteria and others such as fungi, algae, protozoa and actinomycetes. Soil microbes are important in decomposing and recycling of materials in biogeochemical cycles

Answer 101

Is the decomposition of plant and animal residue by using extracellular enzymes of bacteria and fungi. Mineralization helps to remove plant and animal debris from the earth’s surface allowing other organisms to live. And recycles minerals which are found in limited quantities on earth.

Answer 102

All organisms contains large amount of carbon in their bodies as cellulose, starch, fat and proteins 1st step of the carbon cycle is the fixation of atmospheric CO2 by autotrophs and are made available for chemoheterotrophs and protozoans Part of the C fixed in autotrophs and heterotrophs are released back into the atmosphere as CO2 through respiration and made available again for autotrophs Another part of C fixed in chemoheterotrophs is released as faeces which is later decomposed by soil microbes Rest of C fixed remain in organisms until they die and when they are dies it is decomposed and released back into the atmosphere Microbes of carbon cycle consumes more than 80% of the methane produced in ocean beds before reaching the atmosphere

Answer 103

More than 90% of the organic nitrogen of soil exists as proteins. Proteins of dead plants and animals are decomposed by extracellular proteolytic enzymes and are converted to amino acids. These amino acids are taken into microbial cells and undergoes ammonification where the amino groups of amino acids are converted to ammonia and are further converted ammonium once they dissolve in soil water.

Answer 104

Process of converting ammonium ions to nitrate by nitrifying bacteria NH4+ is converted NO2- by Nitrosomans NO2- is converted NO3- by Niitrobacter

Answer 105

In the absence of O2 certain microbes reduce nitrates to N2. Occurs frequently in water-logged areas (pseudomonas sp) NO3-, NO2-,N2O,N2

Answer 106

Process of converting N2 to NH4+

Answer 107

Clostridium sp

Answer 108

Symbiotic interaction between plant roots and soil surrounding the root surface for about few mm. This micro-ecological zone is the most bio-diverse and dynamic habitat on earth. Microbes within the rhizosphere competes for space, nutrients and water of which bacteria are the most common (psedomonas,bacillus and Agrobacterium) Both pathogenic and symbiotic fungi inhabit the rhizosphere

Answer 109

Symbiotic relationship between fungi and plant roots. Almost all land plants are associated with 1 or more mycorrhizal fungi. These fungi increases the surface area over which nutrients and water can be absorbed by the plants, reaches to small pores within soil and increases the uptake of immobile nutrients such as P,Zn,Cu

Answer 110

Involved in the formation of stable soil aggregates such as fungal filaments, actinomycetes filaments and polysaccharide gums produced by bacteria

Answer 111

Should be present consistently in the human faecal matter in large amounts. e.g: coliforms

Answer 112

Bacteria which are aerobic or facultative anaerobic, gram negative, non-endospore forming and rod shaped which ferments lactose to gas within 48 hours in a lactose broth at 35 C

Answer 113

Typhoid, paratyphoid, cholera, gastroenteritis and dysentery

Answer 114

Sedimentation and coagulation Filtration Disinfection

Answer 115

If the water is turbid it is allowed to stand in large reservoirs for a holding period to allow settling of particle matter at the bottom. Enhanced by adding alum (aluminium potassium sulphate) which produces a sticky polysaccharide.

Answer 116

Water is sent through beds of fine sand. Protozoan cysts are removed by the surface absorption onto the sand particles. Removes about 99% of bacteria. Some water treatment plants uses activated carbon for the removal of toxic chemicals.

Answer 117

Done through chlorination or by ozone. O3 is highly reactive and kills microorganisms by oxidation. O3 method is the preferred method as it leaves no taste or odour and has little residual effect.

Answer 118

large floating materials are screened out removal of sand removal of oil and grease solid matter is allowed to settle in sedimentation tanks sludge collected and removed No biological activity is used here and through this step about 25%-35% of organic matter is removed

Answer 119

Waste water is aerated to facilitate growth of aerobic bacteria and rapid microbial oxidation. Activated sludge system or the trickling filter method is used. In activated sludge vigorous aeration is done mechanically and in tricking filter, waste water is slowly sprayed onto a bed of rocky material and allowed trickle. Microbes grow on the filter bed and oxidises organic matter. (75%-95%) Finally water is disinfected Sludge remaining from both the treatments are sent to an anaerobic sludge digester and the organic matter in sludge is converted to CH4 and CO2 by anaerobic decomposition. Digested sludge can be used as a fertiliser.

Answer 120

Dissemination of pathogenic microbes Water pollution due to accumulation of biodegradable materials and their decomposition products Decomposition which cause large consumption of O2 in water which affects aquatic organisms Anaerobic decomposition leading to bad smells

Answer 121

Improper disposal of waste can create breeding sites for mosquitoes, insects and rats which acts as vectors of diseases such as dengue, chickungunya and leptospirosis creates social problems due to bad smell due to anaerobic decomposition of waste accumulation of CH4 can cause explosions and fires transmission of water borne diseases such as typhoid, paratyphoid, cholera, gastroenteritis and dysentery ground water can be polluted due to leachate of waste (liquid pass through waste)

Answer 122

Sorting and recycling Degradation/ decomposition of organic matter (composting) Sanitary. land fillings

Answer 123

Growth of microorganisms on food changes the physical, chemical and biological components of food making it unfit for consumption

Answer 124

Putrefaction Fermentation Rancidity

Answer 125

Proteins in the food source are broken down by proteolytic enzymes secreted by proteolytic microorganisms into amino acids, amines, ammonia and H2S

Answer 126

Complex carbohydrates are broken down into simple carbohydrates by amylase and then the simple carbohydrates are converted into food acids, alcohol and gases by saccharolytic enzymes

Answer 127

Lipids present in the food source is converted into fatty acids and glycerol by lipolytic enzymes

Answer 128

Softening of food Pigmentation Ropiness Slime or gum formation Toxin accumulation

Answer 129

temperature of storage R.H of environment presence and concentration of gases in the environment

Answer 130

pH - most microbes grow best at pH 7, however holds and yeast grow over a wide range (2-10) and bacteria from 5-7 moisture content - high moisture containing food such as meat and fish are spoiled by bacteria and low moisture containing food are spoiled by molds and yeast. nutrient content - nutrient rich food are easily spoiled biological structure - outer covering of fruits, egg shells

Answer 131

Typhoid - Salmonella typhi Cholera - Vibrio cholera Food poisoning - Staphylococcus aureus Dysentery - Shigella Botulism - Clostridium botulinum Aflotoxins - Aspergillus flavus

Answer 132

Food borne infections - microbes enters into the human body through spoiled food and they grow and replicate producing toxins. Symptoms will be developed after some time. e.g: typhoid, cholera and dysentery Food intoxications - Indigested spoiled food contains toxins. Symptoms are rapid. e.g: aflatoxins, botulism and food poisoning Viruses also cause food borne illnesses