Recent questions tagged microbiology

Description : Why is tetanus considered a disease of the nervous system?

Last Answer : Tetanus is a disease caused by a Gram- positive, spore- forming anaerobic rod called Clostridium tetani.This organism often exists in the spore form in the human and animal intestine and passes to ... Since the primary effect is in the nervous system, tetanus is considered a disease of this system.

Description : How is the Gram stain procedure performed in the microbiology laboratory?

Last Answer : In the laboratory, a heat- fixed smear of bacteria is stained with crystal violet for one minute. Then, iodine,which acts as a mordant, is added to the smear for one minute, and the remainder ... the stains are examined under the microscope and the color of the bacteria reveals the Gram reaction.  

Description : What is the advantage of the attenuated viruses in a vaccine?

Last Answer : Attenuated viruses can be taken orally because they will survive passage into the gastrointestinal tract and will be absorbed into the blood stream. The method of administration is therefore easier than by ... this reason they may be advantageous when an epidemic is taking place or is anticipated. 

Description : Why is microbial control necessary and what are some of the factors that go into the choice of a particular antimicrobial agent?

Last Answer : The control of microorganisms is an important way of preventing pathogens from reaching the body.Sterilizing laboratory equipment, hospital supplies, and industrial apparatus helps contain contamination.The choice of a ... , the acidity or alkalinity of the area, and the presence of organic matter. 

Description : Which bacterium is responsible for tuberculosis, and what are the characteristics of the organism?

Last Answer : Tuberculosis is caused by a slender rod known as Mycobacterium tuberculosis. This slow- growing rod is neither Gram- positive nor Gram- negative; rather, it is acid- fast. When stained with ... fast characteristic is due to the presence of a very thick cell wall containing mycolic acid. 

Description : Do all bacteria require oxygen for growth?

Last Answer : Many bacteria are aerobic; that is, they require oxygen to grow and perform the biochemical reactions of their metabolism. There are, however, a large number of bacterial species that are ... obligate anaerobes, while others are facultative anaerobes, meaning that they live with or without oxygen. 

Description : Which microorganisms are involved in the pickling process in food production?

Last Answer : In the pickling process, microorganisms grow and ferment the food in a salty environment while producing large amounts of acid from available carbohydrates. Species of Leuconostoc and Lactobacillus are ... . Different spices are added to prepare various forms of sauerkraut and pickled cucumbers. 

Description : How do microorganisms influence the carbon cycle on Earth?

Last Answer : Most of the organic matter present in soil originates in plant material from leaves, rotting trees, decaying roots, and other tissues. In the carbon cycle, soil bacteria and fungi recycle ... suffer an irreversible decline as the nutrients essential for life became tied up in complex molecules. 

Description : Are bacteria able to move, and, if so, how?

Last Answer : Bacteria (and other prokaryotes) have the ability to move by means of flagella. Flagella are composed of the globular protein flagellin. They are extremely long and thin and cannot be seen by the light ... pair of rings, while Gram- negative bacteria have both inner and outer pairs of rings).  

Description : Are there any unique ways that humans derive benefits from microorganisms?

Last Answer : Humans derive substantial benefits from the activities of microorganisms. For example, many microbial species live in and on various parts of the body and prevent pathogenic bacteria from gaining a ... and used to produce vitamins, enzymes, organic acids, and other essential growth factors.

Description : Are chromosomes the only parts of bacteria that can be transformed?

Last Answer : Bacteria possess extrachromosomal loops of DNA called plasmids. Plasmids are small, self-replicating loops of DNA with about 10 to 50 genes. They are not essential for the survival of the ... process called curing, which can occur spontaneously or can be induced by certain environmental factors. 

Description : What is the general course of development for cases of syphilis?

Last Answer : The etiologic agent of syphilis is the spirochete Treponema pallidum. The organism is motile and can be observed moving about under the dark- field microscope. It is extremely difficult to cultivate in ... - looking face, and damage to the nose. Congenital syphilis may also result in stillbirth.  

Description : Abnormalities in chromosome number give rise to diseases of karyotype. How might these aberrations occur?

Last Answer : Under usual conditions of meiotic division, each tetrad separates into its constituent homologous chromosomes. One homologue migrates to one pole and the other homologue to the opposite pole during ... and internal inversion of chromosomes or chromosome parts may also produce diseases of karyotype. 

Description : What is triclosan?

Last Answer : Triclosan has properties of a phenol and is extremely popular in antibacterial products such as hand sanitizers, antibacterial soaps, lotions, toothpastes, and even as an antimicrobial ... antibiotics. This is of particular concern with antibiotic resistant strains of Staphylococcus aureus. 

Description : What is triclosan? 

Last Answer : Triclosan has properties of a phenol and is extremely popular in antibacterial products such as hand sanitizers, antibacterial soaps, lotions, toothpastes, and even as an antimicrobial ... antibiotics. This is of particular concern with antibiotic resistant strains of Staphylococcus aureus.

Description : Cellulose is the major component of cell walls of (a) Pseudomonas (b) Saccharomyces (c) Pythium (d) Xanthomonas.

Last Answer : (c) Pythium

Description : For retting of jute the fermenting microbe used is (a) methanophilic bacteria (b) butyric acid bacteria (c) Helicobacter pylori (d) Streptococcus lactin.

Last Answer : b) butyric acid bacteria

Description : Bacterial leaf blight of rice is caused by a species (a) Alternaria (b) Erwinia (c) Xanthomonas (d) Pseudomonas.

Last Answer : (c) Xanthomonas

Description : The term phylum was given by (a) Cuvier (b) Haeckel (c) Theophrastus (d) Linnaeus.

Last Answer : (c) Theophrastus

Description : One indirect way to determine microbial growth is using a _____. a. UV light b. Spectrophotometer c. Light meter d. Radioactive counter

Last Answer : b. Spectrophotometer

Description : _____ from the mold Aspergillus oryzaeis used as a spot remover in laundry presoaks, as an adhesive, and in baking, where it digests starch to glucose. a. Amylase b. Lactase c. Sucrase d. Maltase

Last Answer : a. Amylase

Description : The alcoholic content of beer is approximately _____. a. 0.02 b. 0.04 c. 0.06 d. 0.08

Last Answer : b. 0.04

Description : In making beer, in the process of ____ barley grains are steeped in water while naturally occurring enzymes digest the starch to simpler carbohydrates. a. steeping b. mashing c. maltng d. worting

Last Answer : c. maltng

Description : : In the United States, distilled beverages are designated with a "proof number," which is _____ the percentage of the alcohol content. a. half b. one fourth c. twice d. 4 times

Last Answer : c. twice

Description : To the present time, over _____ antibiotic substances have been described and approximately _____ such drugs are available to the medical practitioner. a. 10,000; 100 b. 8,000; 100 c. 6000; 300 d. 4,000; 400

Last Answer : b. 8,000; 100

Description : When the Exxon Valdez oil spill occurred, technologists "fertilized" the oil-soaked water with _____ to modify the environment and stimulate he growth of naturally occurring microorganisms. a. nitrogen sources (e.g., urea) b. phosphorus compounds c. other mineral nutrients d. A-C above are correct

Last Answer : d. A-C above are correct

Description : Bacillus subtilis makes a good "bacterial factory" in genetic engineering because _____. a. it normally retains the products it makes b. it is not a human pathogen c. contains endotoxins in it's cell wall d. traditionally ferments sugars

Last Answer : b. it is not a human pathogen

Description : Some contemporary products already obtained by plasmid technology include a. interferon b. insulin c. human growth hormone d. A-C above are correct

Last Answer : d. A-C above are correct

Description : ______ form the bulk of microbial products of industrial interest. a. primary metabolites b. secondary metabolites c. tertiary metabolites d. quaternary metabolites

Last Answer : b. secondary metabolites

Description : One of the benefits of biofilms is _____. a. quorum sensing b. keeping aquariums clean c. bioremediation of toxic wastes d. production of oil

Last Answer : c. bioremediation of toxic wastes

Description : In 1842, Edwin Chadwick's report raised the possibility that sewage spreads disease along with a ______ outbreak which began the ________ movement. a. typhoid, aseptic b. cholera, sanitation c. polio, immunization d. none of the above are correct

Last Answer : b. cholera, sanitation

Description : _______ disease develops on the hands or feet. Sores on the skin become infected with Mycobacterium marinum in polluted water or in infected fish. a. Fish handlers b. Cholera c. Cowpox d. Rotovirus e. Coxsackie

Last Answer : a. Fish handlers

Description : Rhizobium fixes nitrogens in the roots of _____, so they don't need to be fertilized; in fact they add nitrogen to the soil. a. corn b. legumes c. wheat d. grasses e. oats

Last Answer : b. legumes

Description : Some scientists‘ estimate that in nature, _____ of all microbial activities occur in biofilms. a. 0.25 b. 0.33 c. 0.45 d. 0.6 e. 0.99

Last Answer : e. 0.99

Description : _____ bacteria live as individuals and do not live in biofilms. a. Planktonic b. Anaerobic c. Aerobic d. Facultative anaerobic

Last Answer : a. Planktonic

Description : An emerging pathogen associated with contaminated water is _____. a. typhoid fever b. cholera c. shigellosis d. Vibrio vulnificus

Last Answer : d. Vibrio vulnificus

Description : Which of the following is NOT one of the 3 main types of water pollution? a. Physical pollution b. Chemical pollution c. Thermal pollution d. Biological pollution

Last Answer : c. Thermal pollution

Description : Polluted water usually contains coliform bacteria like _____. a. Streptococcus b. Proteus c. Escherichia coli d. Pseudomonas

Last Answer : c. Escherichia coli

Description : _____ is water that is safe to drink. a. Potable water b. Surface water c. Well water d. Ground water

Last Answer : a. Potable water

Description : Approximately 33% of all preserved food in the United States is______. a. canned b. frozen c. dehydrated d. pasteurized

Last Answer : b. frozen

Description : The modern refrigerator is set at _____ to provide a suitable environment for preserving food without destroying appearance, or taste. a. 30°F b. 35°F c. 40°F d. 45°F e. 50°F

Last Answer : c. 40°F

Description : _____ is used to make processed cheeses and "cheese foods." a. Sour curd b. Sweet curd c. Whey d. Butterfat

Last Answer : c. Whey

Description : Two types of grain spoilage are _____ and _____. A. aflatoxins, ergotism a. botulism, ergotism b. Staphlococcus, Streptococcus c. aflatoxins, enterotoxins

Last Answer : A. aflatoxins, ergotism

Description : Processed foods such as chicken pot pies, whole egg custard, mayonnaise, eggnog, and egg salad also may be sources of a. Staphylococcus b. Chlamydia c. Salmonella d. E.coli

Last Answer : c. Salmonella

Description : Many cases of _____ have been related to raw oysters. a. botulism b. cholera c. typhoid d. food poisoning

Last Answer : b. cholera

Description : Bacterial species in fish are naturally adapted to the cold environment in which most fish live and thus, _____ will not affect them; _____ is preferred. a. heating, cooking b. cooling, refrigeration c. warming, boiling d. cooling, freezing

Last Answer : d. cooling, freezing

Description : _________foods include poultry, eggs, meats, most vegetables and fruits. a. Nonperishable b. Semiperishable c. Highly perishable d. Antibacterial

Last Answer : c. Highly perishable

Description : Food must be moist, with a minimum water content of _____before contamination by microorganisms and spoilage can occur. a. 18% to 20% b. 10 to 15% c. 5 to 10% d. 0 to 5%

Last Answer : a. 18% to 20%

Description : Spoiled food can be caused from _____. a. enterotoxins in food b. contaminating microorganisms from the air c. human food handling d. A-C are correct

Last Answer : d. A-C are correct

Description : Antibiotics will not work against _____ diseases because they lack the structures and metabolic machinery with which antibiotics interfere. a. viral b. bacterial c. fungal d. protozoan

Last Answer : a. viral