Microbes in Biology

<p>Facultative anaerobic</p> Signup and view all the answers

<p>Fungal spores</p> Signup and view all the answers

<p>Bacteria</p> Signup and view all the answers

<p>Food Microbiology</p> Signup and view all the answers

<p>Microalgae</p> Signup and view all the answers

<p>Fungi</p> Signup and view all the answers

<p>Humidity</p> Signup and view all the answers

<p>Staining with crystal violet-iodine complex</p> Signup and view all the answers

<p>10nm for viruses, 1µm for bacteria</p> Signup and view all the answers

<p>By inserting genetic materials into host cells</p> Signup and view all the answers

<p>Chlorella zofingiensis</p> Signup and view all the answers

<p>Single-celled, eukaryotic organisms</p> Signup and view all the answers

<p>Archaebacteria</p> Signup and view all the answers

<p>Cell shape, size, and structure arrangement</p> Signup and view all the answers

<p>Protista</p> Signup and view all the answers

<p>All of the above</p> Signup and view all the answers

<p>Based on specific characteristics such as cell shape, size, and structure arrangement</p> Signup and view all the answers

<p>Archaebacteria</p> Signup and view all the answers

<p>Cholera, avian influenza, and ciguatera food poisoning</p> Signup and view all the answers

<p>Based on their cell shape, size, and structure arrangement</p> Signup and view all the answers

<p>Both single-celled (yeasts) and multi-celled (molds) organisms</p> Signup and view all the answers

<p>By serving as a source of drugs</p> Signup and view all the answers

<p>The six kingdoms into which microorganisms are classified include Protista, Fungi, Archaebacteria, Eubacteria, Plantae, and Animalia.</p> Signup and view all the answers

<p>Microorganisms are classified based on characteristics such as cell shape, size, and structure arrangement.</p> Signup and view all the answers

<p>Microorganisms can be detected in food using specific methods.</p> Signup and view all the answers

<p>Examples of foodborne diseases caused by microorganisms include cholera, avian influenza, and ciguatera food poisoning.</p> Signup and view all the answers

<p>Protista can exhibit different modes of growth like photoautotrophic, heterotrophic, and mixotrophic.</p> Signup and view all the answers

<p>The classification of microorganisms mentioned in the text includes prokaryotic microorganisms (e.g. bacteria), eukaryotic microorganisms (e.g. fungi, microalgae, protozoa), and viruses.</p> Signup and view all the answers

<p>The factors affecting microbial growth mentioned in the text are nutrition, temperature, pH, light requirement, and the growth curve.</p> Signup and view all the answers

<p>Beneficial applications of microorganisms in daily life mentioned in the text include the production of foods such as beer, cheese, and soy sauce, as well as the production of nutritional foods like Spirulina cereal and Fat Choi.</p> Signup and view all the answers

<p>The nutritional supplements and antioxidants mentioned to be produced by microorganisms include phycocyanin produced by Spirulina, omega-6 &amp; omega-3 polyunsaturated fatty acids (PUFAs) such as Arachidonic acid (AA) produced by fungi, and Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA) produced by diatoms and dinoflagellates.</p> Signup and view all the answers

<p>The text mentions the production of fermented foods by microorganisms, giving examples such as the production of foods through fermentation.</p> Signup and view all the answers

<p>Molds contain thread-like filaments called hyphae, and when hyphae extend and form a large mass, it is called a mycelium. They reproduce by forming spores, which disperse from the parent and germinate under favorable conditions.</p> Signup and view all the answers

<p>Yeasts are single-celled, eukaryotic organisms that grow best at pH 4.5 – 5 and at a temperature of 20 – 30°C. They can grow in the presence and absence of oxygen (facultative anaerobic). Yeasts are important in the food industry as starters for producing fermented foods.</p> Signup and view all the answers

<p>Microbes that require oxygen for growth are classified as aerobic, while those inhibited by oxygen are classified as anaerobic. Facultative anaerobic microbes can grow in both aerobic and anaerobic environments. For example, Saccharomyces cerevisiae can grow aerobically in the presence of oxygen and change to anaerobic growth when oxygen is deficient.</p> Signup and view all the answers

<p>Agar plates/broth provide nutrients for bacterial growth, making them useful for maintaining and studying microbial cultures.</p> Signup and view all the answers

<p>Yeasts, such as Saccharomyces cerevisiae, are crucial in the food industry as starters for producing fermented foods. This includes the production of bread, beer, and wine.</p> Signup and view all the answers

<p>Bacteria gram staining involves fixed cells on a slide and staining with crystal violet-iodine complex.</p> Signup and view all the answers

<p>Viruses have a size of 10nm, whereas bacteria cells have a size of 1µm.</p> Signup and view all the answers

<p>Green microalgae like Chlamydomonas and Chlorella can reproduce asexually or sexually.</p> Signup and view all the answers

<p>Chlorella zofingiensis is known for producing Astaxanthin, a red carotenoid, while Chlorella protothecoides produces Lutein, a yellow carotenoid.</p> Signup and view all the answers

<p>Ciguatera, caused by Gambierdiscus toxicus, is an example of food poisoning caused by Protozoa.</p> Signup and view all the answers

<p>Viruses are generally much smaller than bacteria and can only replicate inside the living cells of organisms.</p> Signup and view all the answers

<p>Humans usually get infected with viruses via ingestion, shedding in feces, contaminated water sources, and food contamination caused by food handlers or carriers.</p> Signup and view all the answers

<p>Primary contamination occurs when food is naturally contaminated during primary production. An example is filter-feeding shellfish being contaminated at the water source.</p> Signup and view all the answers

<p>Secondary contamination is caused by food handlers, carriers, or the contaminated food preparation area.</p> Signup and view all the answers

<p>Three common viruses causing foodborne illness are Norovirus, Rotavirus, and Hepatitis A virus.</p> Signup and view all the answers

<p>The TDT curve shows the relationship between temperature and time needed to kill microorganisms.</p> Signup and view all the answers

<p>The D-value is the time required to kill 90% of microbial population and varies with temperature.</p> Signup and view all the answers

<p>Refrigeration (2-8˚C) slows microbial growth.</p> Signup and view all the answers

<p>MAP alters the gaseous environment to preserve food freshness.</p> Signup and view all the answers

<p>Dehydration inhibits microbial growth by reducing water activity.</p> Signup and view all the answers

<p>Aims of food preservation include preventing spoilage, extending shelf life, minimizing spoilage microorganisms, and ensuring food safety. Principles of food preservation include the elimination or inactivation of microorganisms, stopping enzyme action, and preventing oxidation through physical, chemical, and biological methods of food preservation.</p> Signup and view all the answers

<p>Norovirus symptoms include vomiting, diarrhea, fever, and nausea. It is mainly transmitted through hand-to-mouth contact, direct contact, and consumption of contaminated shellfish and salad.</p> Signup and view all the answers

<p>Rotavirus causes vomiting, diarrhea, nausea, fever, and potentially death in severe cases. It is transmitted through fecal-oral and person-to-person transmission, food and waterborne.</p> Signup and view all the answers

<p>Hepatitis A virus infection has an onset time of 12-50 days and symptoms including fatigue, diarrhea, liver damage, and extensive liver damage.</p> Signup and view all the answers

<p>Molds primarily produce mycotoxins, causing foodborne illnesses like ergot poisoning from Claviceps purpurea, affecting neurons and leading to symptoms such as vision problems, confusion, unconsciousness, and gangrene in toes and fingers. Aflatoxin poisoning, caused by Aspergillus species, occurs in grains and nuts under damp and warm conditions, and its symptoms include liver degeneration, tumor, and stunted growth in children.</p> Signup and view all the answers

<p>Pasteurization is a thermal process used to inactivate enzymes and eliminate viable pathogenic microorganisms from heat-sensitive foods such as milk, fruit juice, wine, and egg. It involves heating the food to below 100˚C for a specific duration and then rapidly cooling it to slow down microbial growth, requiring refrigeration storage and providing a shelf life of 2-3 weeks.</p> Signup and view all the answers

<p>The two main methods of pasteurization are low-temperature pasteurization at 63˚C for 30 minutes and high-temperature short time (HTST) pasteurization at 72˚C for 15 seconds.</p> Signup and view all the answers

<p>Ultra-high temperature (UHT) pasteurization of raw milk involves heating the milk to around 138 °C for 2-3 seconds, then rapidly cooling and packaging it in sterile, hermetically-sealed containers, providing a shelf-stable product for 6 months without requiring refrigeration until opened.</p> Signup and view all the answers

<p>Sterilization is a process that completely kills or removes all life forms, including bacteria and other organisms, and is commonly achieved through heating methods such as wet heating at 121°C for 15-20 minutes.</p> Signup and view all the answers

<p>D value represents the time needed to reduce the number of a given microorganism by 90% at a specific temperature, and it decreases as the temperature increases, differing for different microbial species.</p> Signup and view all the answers