MCQ2 Some Revision Questions PDF

Gram positives in general What is the material found in the cell wall of Gram positive and Gram negative bacteria? (a) (b) (c) (d) Peptidoglycan is a (a) (b) (c) (d) What is the chemical composition of peptidoglycan? (a) (b) (c) (d) The sugars found in the peptidoglycan layer are: (a) (b) (c) (d...

Gram positives in general What is the material found in the cell wall of Gram positive and Gram negative bacteria? (a) (b) (c) (d) Peptidoglycan is a (a) (b) (c) (d) What is the chemical composition of peptidoglycan? (a) (b) (c) (d) The sugars found in the peptidoglycan layer are: (a) (b) (c) (d) The abbreviations for the two sugars found in peptidoglycan are (a) (b) (c) (d) How many amino acids are generally found in the amino-acid cross-link in peptidoglycan? (a) (b) (c) (d) The amino acids found in the oligopeptide found in Peptidoglycan are (a) (b) (c) (d) Which of the two sugars in the peptidoglycan is connected to the amino-acid cross-link? (a) (b) (c) (d) Name an amino acid in the amino-acid cross-link in peptidoglycan, which is not found in Eukaryotes (a) (b) (c) (d) What is the significance of the letter L or D before the amino acid name? (a) (b) (c) (d) How many layers of the Peptidoglycan polymer are found in Gram positive bacteria? (a) (b) (c) (d) The molecules embedded within the peptidoglycan but protruding on the surface in Gram positive bacteria is called (a) (b) (c) (d) Lipoteichoic acid is (a) (b) (c) (d) Teichoic acid is (a) (b) (c) (d) Lipoteichoic acid differs from Teichoic acid by virtue of (a) (b) (c) (d) As far as the human immune system is concerned, which molecules on the cell surface act as antigens in Gram-positives? (a) (b) (c) (d) The purpose of Teichoic acids for the bacterium is (a) (b) (c) (d) What kind of molecule is the teichoic acid? (a) (b) (c) (d) The curved part of the flagellum protruding from the cell is called (a) (b) (c) (d) The structure at the bottom of the flagellum, in contact with the plasma membrane, is called the (a) (b) (c) (d) What is the S-layer? (a) (b) (c) (d) In Gram positives, the S-layer, if present, is attached to (a) (b) (c) (d) In Gram negatives, if present, the S-layer is attached to (a) (b) (c) (d) What is the S-layer composed of? (a) (b) (c) (d) Gram-positives are divided into two main groups, namely (a) (b) (c) (d) The principal metabolic difference between staphylococci and streptococci is (a) (b) (c) (d) Within the common Gram-positive bacteria, the two best known coccus groups are? (a) (b) (c) (d) Staphylococci are divided into two main groups, namely (a) (b) (c) (d) Where are bacilli found? (a) (b) (c) (d) What shape are bacilli? (a) (b) (c) (d) The species name of the Bacillus that causes food poisoning is (a) (b) (c) (d) Bacilli are often used in industry for the production of what valuable enzymes? (a) (b) (c) (d) The two Gram-positive bacterial genera that form endospores are (a) (b) (c) (d) Clostridium botulinum produces a very powerful what? (a) (b) (c) (d) Which of the following species of Clostridium causes food-poisoning? (a) (b) (c) (d) Which of the following species of Clostridium causes intestinal infections in hospitals? (a) (b) (c) (d) Which part of the human body is the best place to isolate Staphylococcus aureus from? (a) (b) (c) (d) The following are toxins produced by Staphylococcus aureus (a) (b) (c) (d) Pick a bacterium commonly found in abscesses (boils): (a) (b) (c) (d) The methylated form of penicillin, which is also used as an antibiotic is called: (a) (b) (c) (d) The abbreviation for a Staphylococcus aureus, which is resistant to the methylated form of penicillin is: (a) (b) (c) (d) Listeria The species of Listeria commonly associated with human disease is (a) (b) (c) (d) How many species of Listeria exist? (a) (b) (c) (d) Listeriosis in animals is (a) (b) (c) (d) Listeriosis in humans is (a) (b) (c) (d) Listeria accumulates in which body tissues? (a) (b) (c) (d) What effect can listeriosis have on pregnant women? (a) (b) (c) (d) Which human groups are most susceptible to serious infection by Listeria? (a) (b) (c) (d) The most dangerous property about Listeria monocytogenes in food is that it can grow at which temperature? (a) (b) (c) (d) Where human and animal cells are concerned, Listeria monocytogenes has the ability to (a) (b) (c) (d) Sources of Listeria monocytogenes in the environment include the following: (a) (b) (c) (d) Food sources of Listeria monocytogenes include the following: (a) (b) (c) (d) How does Listeria monocytogenes get into food-processing plants? (a) (b) (c) (d) Food sources of Listeria monocytogenes include the following: (a) (b) (c) (d) How does Listeria monocytogenes get into food-processing plants? (a) (b) (c) (d) What kind of areas in a food processing plant would you expect to find Listeria monocytogenes? (a) (b) (c) (d) Listeria can be found in biofilms on equipment. A biofilm is (a) (b) (c) (d) Many different microbes make biofilms. The first stage in biofilm formation is (a) (b) (c) (d) Bacteria that form a biofilm produce what kind of extracellular molecule? (a) (b) (c) (d) What kind of surfaces can biofilms form on? (a) (b) (c) (d) Listeria monocytogenes is resistant to high levels of (a) (b) (c) (d) What levels of Listeria monocytogenes are permitted in foods? (a) (b) (c) (d) Once Listeria monocytogenes gets into the gastrointestinal tract, the bacterial cells are (a) (b) (c) (d) In the USA, there is an organization called the CDC, from where we obtain many relevant disease statistics. What does CDC stand for? (a) (b) (c) (d) In the USA, there is an organization called the USDA which sets standards for specific microbes in foods. What does USDA stand for? (a) (b) (c) (d) In Listeria monocytogenes outbreaks, as a percentage of the number of cases, the death rate can be as high as (a) (b) (c) (d) Which group of people is warned not to eat foods which may contain Listeria monocytogenes? (a) (b) (c) (d) What is actin? (a) (b) (c) (d) What is actin-based motility? (a) (b) (c) (d) What effect does Listeria monocytogenes have on the actin cytoskeleton? (a) (b) (c) (d) Virulence factors in Listeria monocytogenes are (a) (b) (c) (d) Which of the following agar media is used to test for Listeria monocytogenes are (a) (b) (c) (d) Which molecular technique is sometimes used to confirm presence of Listeria? (a) (b) (c) (d) What does PCR stand for? What is an oligonucleotide primer? (a) (b) (c) (d) How many oligonucleotide primers are typically used in a PCR reaction? (a) (b) (c) (d) The three principal steps in PCR are named as follows: (a) (b) (c) (d) The three principal steps in a PCR are controlled by changing what property? (a) (b) (c) (d) How many cycles are usually done to complete a PCR? (a) (b) (c) (d) What are the main ingredients in a PCR reaction? (a) (b) (c) (d) What enzyme is used in the PCR reaction to make the amplified DNA? (a) (b) (c) (d) Give the correct name for the PCR machine (a) (b) (c) (d) The PCR machine is essentially an elaborate programmable ……….. (what?). (a) (b) (c) (d) There’s a PCR kit for detecting Listeria, which only detects living cells. What extra enzyme is used in this kit to ensure that only living cells are detected? (a) (b) (c) (d) Bacillus The genus Bacillus includes bacteria which are (a) (b) (c) (d) Sources of Bacillus include: (a) (b) (c) (d) The following species belong to the genus Bacillus (a) (b) (c) (d) B. amyloliquefaciens is a source of which enzymes? (a) (b) (c) (d) B. anthracis is a dangerous pathogen that causes what? (a) (b) (c) (d) B. cereus is commonly associated with what? (a) (b) (c) (d) B. coagulans is sometimes used as a what? (a) (b) (c) (d) B. subtilis is very well studied and often used in teaching labs. If it gets into flour, what problem can it cause in bread? (a) (b) (c) (d) B. stearothermophilus grows at high temperatures; its spores are used as an indicator to validate what? (a) (b) (c) (d) B. thuringiensis is used as biological control agent for what? (a) (b) (c) (d) Which stain is used to stain a bacterial endospore? (a) (b) (c) (d) Bacillus is generally good at secreting (a) (b) (c) (d) Bacillus-derived Pectinase degrades (a) (b) (c) (d) Bacillus-derived Lecithinase degrades (a) (b) (c) (d) Bacillus-derived protease degrades (a) (b) (c) (d) Bacillus-derived haemolysin breaks down (a) (b) (c) (d) Colonies of Bacillus are generally (a) (b) (c) (d) Subtilisin is an enzyme which breaks down (a) (b) (c) (d) Subtilisin is an ingredient in which common domestic product (a) (b) (c) (d) Activity of subtilisin has been improved by a procedure called (a) (b) (c) (d) Which member of the genus Bacillus is used as an insecticide? (a) (b) (c) (d) Name an agricultural crop, which has a Bacillus gene incorporated into its genome (a) (b) (c) (d) Which is the most dangerous of the following Bacillus species: (a) (b) (c) (d) Which species of Bacillus is associated with food-borne intoxication (a) (b) (c) (d) A food-borne intoxication is (a) (b) (c) (d) The difference between the two toxins produced by Bacillus cereus is that (a) (b) (c) (d) Which of the following foods is associated with Bacillus cereus intoxication: (a) (b) (c) (d) Bacillus cereus, which is associated with food-borne intoxication produces how many toxins (a) (b) (c) (d) Clostridia Clostridia are (a) (b) (c) (d) Clostridia are present in (a) (b) (c) (d) Where clostridia are growing, the smell generated is (a) (b) (c) (d) Like Bacillus, clostridia secrete a number of (a) (b) (c) (d) In the environment, clostridia play an important role in (a) (b) (c) (d) The following two species are members of the genus Clostridium: (a) (b) (c) (d) Clostridium botulinum toxin is a (a) (b) (c) (d) Clostridium botulinum toxin causes (a) (b) (c) (d) The site of action of botulinum toxin is (a) (b) (c) (d) Which of the following food-packaging systems is associated with botulism? (a) (b) (c) (d) What is the Botulinum Cook? (a) (b) (c) (d) Minimum Botulinum Cook is usually measured in (a) Bacterial cell numbers in CFU per gram. (b) Degrees Centigrade (OC) (c) Minutes (d) Degrees Farenheit (OF) Thermal death time at a given temperature is (a) The time taken to kill off all bacteria in a sample (e.g. a can) by 12 log (b) The time taken to reduce bacteria in a sample (e.g. a can) by one log (c) The time taken to reduce bacteria in a sample (e.g. a can) by 50% (d) The time taken to reduce bacteria in a sample (e.g. a can) by 10% Thermal death time at a given temperature is (a) The time taken to reduce the bacterial number 10-fold (b) The time taken to reduce the bacterial number 90-fold (c) The time taken to reduce the bacterial number 100-fold (d) The time taken to reduce bacteria in a sample 2 fold Thermal death time at a given temperature is (a) The time taken to reduce the bacterial number by 10% (b) The time taken to reduce the bacterial number by 90% (c) The time taken to reduce the bacterial number by 50% (d) The time taken to reduce the bacterial number by 100% If it takes 1 minute at 115OC to reduce the number of Clostridia in a sample 10-fold. What is the correct Minimum Botulinum Cook for the sample at 115OC. (a) 12 minutes (b) 24 minutes (c) 120 minutes (d) 240 minutes If it takes 3 minutes at 108OC to reduce the number of Clostridia in a sample by one log. What is the correct Minimum Botulinum Cook for the sample at 108OC. (a) 36 minutes (b) 24 minutes (c) 12 minutes (d) 72 minutes The Minimum Botulinum Cook applied to a can of meat at 110OC is 24 minutes. What is the thermal death time for C.botulinum at this temperature (D110)? (a) 2.4 minutes rounded up to 3 minutes (b) 110 minutes (c) 24 minutes (d) 2 minutes The thermal death time for C.botulinum is 3 minutes at 108OC (i.e. D108), what is the correct Minimum Botulinum Cook for the sample at this temperature? (a) 36 minutes (b) 24 minutes (c) 12 minutes (d) 6 minutes The thermal death time for C.botulinum is 30 seconds at 121OC (i.e. D121), what is the correct Minimum Botulinum Cook for the sample at this temperature? (a) 36 minutes (b) 24 minutes (c) 12 minutes (d) 6 minutes In the context of thermal death time, reducing the bacterial number by one log means (a) reducing the bacteria by 10% (i.e. only 90% are left alive) (b) reducing the bacteria by 90% (i.e. only 10% are left alive) (c) reducing the bacteria by 100% (i.e. only 0% are left alive) (d) reducing the bacteria 100-fold (i.e. only 1% are left alive) Reducing the bacterial number by two logs means (a) reducing the bacteria by 20% (i.e. only 80% are left alive) (b) reducing the bacteria 2-fold (i.e. only 50% are left alive) (c) reducing the bacteria 10-fold (i.e. only 10% are left alive) (d) reducing the bacteria 100-fold (i.e. only 1% are left alive) If you had 1,000,000 bacteria in a sample and you reduced the number by 3 log, how many bacteria would be left? (a) 1000 (b) 106 (c) 100 (d) 104 If you had 1,000 bacteria in a sample and you reduced the number by 2 log, how many bacteria would be left? (a) 998 (b) -2.0 x 103 (c) 10 (d) 102 When the botulinum cook is done correctly, the chances of Clostridium botulinum surviving is (a) (b) (c) (d) In which situation is the Botulinum Cook difficult to enforce? (a) (b) (c) (d) Which Clostridium species causes food-poisoning very commonly (a) (b) (c) (d) Clostridium perfringens in food produces what kind of toxin? (a) (b) (c) (d) What situation commonly gives rise to Clostridium perfringens food poisoning? (a) (b) (c) (d) Clostridium perfringens also causes a nasty flesh infection called: (a) (b) (c) (d) Tetanus toxin is a (a) (b) (c) (d) Tetanus toxin has the following effect: (a) (b) (c) (d) Which species of the genus Clostridium causes antibiotic-associated diarrhoea: (a) (b) (c) (d) Antibiotic-associated diarrhea is (a) (b) (c) (d) The following species are members of the genus Clostridium: (a) (b) (c) (d) How would you incubate your plates when trying to isolate clostridia? (a) (b) (c) (d) Topic n: Staphs and micrococci Staphylococci are named as such because under the microscope the cells look like (a) (b) (c) (d) Where oxygen utilization is concerned, Staphylococci and Micrococci are (a) (b) (c) (d) Micrococci make up 90% of the flora of are (a) (b) (c) (d) The following is a species of Micrococcus (a) (b) (c) (d) The following is a species of Staphylococcus (a) (b) (c) (d) Staphylococcus aureus produces many (a) (b) (c) (d) Today, Staphylococcus aureus is resistant to many (a) (b) (c) (d) The habitat of Staphylococcus aureus is (a) (b) (c) (d) A good medium to select for Staphylococcus aureus is (a) (b) (c) (d) The following features can be seen around a colony of Staphylococcus aureus on Baird Parker medium is (a) (b) (c) (d) The halo of clearing around a colony of Staphylococcus aureus on Baird Parker medium is due to (a) (b) (c) (d) The black colour of a colony of Staphylococcus aureus on Baird Parker medium is due to (a) (b) (c) (d) What supplement is added to Baird Parker medium? (a) (b) (c) (d) What is coagulase? (a) (b) (c) (d) Why does Staphylococcus aureus make coagulase? (a) (b) (c) (d) How is the coagulase test done? (a) (b) (c) (d) Which type of haemolysis causes clearing of blood agar? (a) (b) (c) (d) Which type of haemolysis causes partial greenish clearing of blood agar? (a) (b) (c) (d) What does Staphylococcus aureus make in food? (a) (b) (c) (d) The toxin made by Staphylococcus aureus in food is (a) (b) (c) (d) Which of the following foods is most likely to get contaminated with Staphylococcus aureus? (a) (b) (c) (d) The most common source of Staphylococcus aureus in the context of food contamination is (a) (b) (c) (d) Lactic acid bacteria The main role of lactic acid bacteria in fermented foods is (a) (b) (c) (d) The following food is made using lactic acid bacteria: (a) (b) (c) (d) The following is a typical cell shape among lactic acid bacteria: (a) (b) (c) (d) With regard to oxygen utilization, all lactic acid bacteria are (a) (b) (c) (d) Fermentation of one lactose molecule by a lactic acid bacterium generates how many molecules of ATP? (a) (b) (c) (d) The Lactic acid molecule has different (a) (b) (c) (d) The four functional groups attached to the central carbon in lactic acid are (a) (b) (c) (d) Lactic acid bacteria which carry out the heterolactic fermentation produce the following in addition to lactic acid (a) (b) (c) (d) Lactic acid bacteria which carry out the homolactic fermentation just produce (a) (b) (c) (d) From a nutritional point of view, Lactic acid bacteria are (a) (b) (c) (d) The genus Streptococcus includes the following species: (a) (b) (c) (d) Streptococcus mutans is usually found where? (a) (b) (c) (d) Streptococcus agalactiae and Streptococcus dysgalactiae cause (a) (b) (c) (d) Streptococcus pyogenes is associated with which infection? (a) (b) (c) (d) Group A streptococci cause: (a) (b) (c) (d) Lactococcus lactis grows in (a) (b) (c) (d) Lactococcus lactis is usually used to make (a) (b) (c) (d) The sugar found in milk (Lactose) is composed of the following two monosaccharide molecules: (a) (b) (c) (d) The ability of Lactococcus lactis to grow in milk is a property which (a) (b) (c) (d) Plasmids are (a) (b) (c) (d) Conjugation is an event where (a) (b) (c) (d) When a cell divides the plasmids (a) (b) (c) (d) Integration of a plasmid into the chromosome means (a) (b) (c) (d) The genus Enterococcus includes the following species (a) (b) (c) (d) An example of one well-known antibiotic resistant Enterococcus is (a) (b) (c) (d) The genus Lactobacillus includes the following species (a) (b) (c) (d) The shape of the Lactobacillus cell is (a) (b) (c) (d) Lactobacillus species have a wide range of applications including (a) (b) (c) (d) Lactobacillus species sometimes cause spoilage of (a) (b) (c) (d) Pediococcus species sometimes cause spoilage of (a) (b) (c) (d) Energy and Metabolism (principles) Energy extracted from molecules such as sugars is used for what by microbes (a) (b) (c) (d) Metabolism is divided into two types namely: (a) (b) (c) (d) A metabolic pathway is: (a) (b) (c) (d) Control of metabolism is brought about by: (a) (b) (c) (d) ATP stands for: (a) (b) (c) (d) ATP releases energy when which part of the ATP molecule is released? (a) (b) (c) (d) When ATP looses one phosphate, it becomes: (a) (b) (c) (d) When ADP looses one phosphate, it becomes: (a) (b) (c) (d) When ATP drives an endergonic (energy-requiring) reaction, the energy is transferred to the reaction from ATP by: (a) (b) (c) (d) Regeneration of ATP means: (a) (b) (c) (d) Energy for regeneration of ATP comes from: (a) (b) (c) (d) Topic r: Microbial Metabolism (in detail) What are the two main energy-yielding metabolic processes that occur in heterotrophic bacteria? (a) (b) (c) (d) Breakdown of sugar (glucose) to yield energy in living things involves three major universal pathways, namely: (a) (b) (c) (d) Aerobic respiration is a series of reactions in which: (a) (b) (c) (d) In glycolysis, glucose is broken down in a number of steps into two molecules of: (a) (b) (c) (d) How many major varieties of glycolysis exist in the microbial world? (a) (b) (c) (d) In yeasts, plants, animals, humans and many bacteria the type of glycolysis pathway is known as the (a) (b) (c) (d) Krebs cycle is also known as (a) (b) (c) (d) In Kreb’s cycle the electron-carrier molecule that carries away the electrons (that were originally present the chemical bonds in the sugar) is called: (a) (b) (c) (d) In Krebs cycle, which gas is released? (a) (b) (c) (d) What is brought to the electron transport chain to set the process going? (a) (b) (c) (d) At the end of the electron transport chain, where do the electrons end up? (a) (b) (c) (d) In aerobic free-living bacteria, the proteins involved in the electron transport chain are located where? (a) (b) (c) (d) Aerobic respiration is very efficient at making ATP. For every molecule of glucose broken down, the number of ATP molecules made is: (a) (b) (c) (d) Fermentation is an inefficient process for making ATP. For every molecule of glucose broken down, the number of ATP molecules made is usually: (a) (b) (c) (d) The fermentative bacterial genus used in the making of Swiss cheese is also found in acne in teenagers. Name the genus. (a) (b) (c) (d) Fermentation is used by the following bacterial genera to make industrially important products: (a) (b) (c) (d) What microorganism carries out the alcoholic fermentation? (a) (b) (c) (d) What group of bacteria carries out the lactic acid fermentation? (a) (b) (c) (d) Name a bacterium that carries out the mixed acid fermentation? (a) (b) (c) (d) What bacterial genus carries out the propionic acid fermentation? (a) (b) (c) (d) DNA/genes and operons The term polyribosome refers to what phenomenon in prokaryotes? (a) (b) (c) (d) A promotor is a sequence of DNA which is important for (a) (b) (c) (d) Where is the promotor sequence located? (a) (b) (c) (d) Inverted repeats in DNA facilitate the formation of what? (a) (b) (c) (d) In transcription, the enzyme RNA polymerase attaches to the DNA upstream of the gene at what specific location? (a) (b) (c) (d) The sequence for the Ribosome Binding Site on the DNA is located where? (a) (b) (c) (d) What molecule(s) in the ribosome does the Ribosome Binding Site sequence on the mRNA attach to? (a) (b) (c) (d) On a tRNA molecule, what is the function of the anti-codon? (a) (b) (c) (d) The start codon always encodes which amino acid? (a) (b) (c) (d) The sequence of the start codon as it appears on the mRNA is (a) (b) (c) (d) The sequence of the start codon as it appears on DNA is (a) (b) (c) (d) The non-sense codons are also known as what? (a) (b) (c) (d) An operon is an organization of genes on DNA where (a) (b) (c) (d) In the Lac Operon, the molecule which causes transcription to be switched off is called (a) (b) (c) (d) In the Lac Operon, the molecule which causes transcription to be switched on is (a) (b) (c) (d) In the Lac Operon, the operator sequence is responsible for what? (a) (b) (c) (d) Transcription of the structural genes on the Lac operon are turned off when the bacterium finds itself in what kind of environment? (a) (b) (c) (d) Indicate the correct order of the following features on the DNA in typical operon (a) 1: Structural genes 2: Promotor, 3: Ribosome binding site, 4: Transcriptional start point, 5:. Operator (b).. other combinations of the above (c).. other combinations of the above (d).. other combinations of the above The transcriptional start point on the DNA is the point which marks the beginning of synthesis which molecule? What molecule attaches to the promotor sequence? (a) (b) (c) (d) The benefit of bacteria having operons is that it prevents (a) (b) (c) (d) What biological entity is necessary for transduction (a) (b) (c) (d) Transformation in bacteria means: (a) (b) (c) (d) Why is Transformation so called in bacteria? (a) (b) (c) (d) What is transfection? (a) (b) (c) (d) Resistance plasmids encode (a) (b) (c) (d) Virulence plasmids encode (a) (b) (c) (d) Conjugative plasmids encode (a) (b) (c) (d) Metabolic plasmids encode (a) (b) (c) (d) What happens to bacteriophage DNA in the bacterium in the case of a lysogenic cycle? (a) (b) (c) (d)