Microbiology Quiz 4

Which is the indirect method of measuring microbial growth? Plate counts Filtration Turbidity MPN Direct microscopic count

Turbidity

Which of the following methods of measuring microbial growth uses light as it's source? Filtration Turbidity Plate count a & b b & c

Turbidity

Why do microorganisms create antibiotics? A) It helps protect them from the target B) It requires no energy input so it is not problematic C) They are vestiges and have no effect D) That antibiotics to communicate in the biofilm E None of the above

D) That antibiotics to communicate in the biofilm Not quite sure what you are trying to ask here . . . Antibiotics are compounds produced by microbes (usually fungi) to inhibit the growth of other microbes (usually bacteria), thus giving the antibiotic-producing microbes a competitive edge in the same environment.

How can antimicrobials kill bacteria? A) Alter their cell walls B) damage proteins C) damage their nucleic acids D) all of the above E) none of the above

D) all of the above

The method of binary fission explain how bacteria. . . (level 1) A) form a mitotic spindle B) move C) grow in agar D) divide and reproduce E) evolve

D) divide and reproduce

Assume you are an RN working in a nursing home. One of your residents is presenting with a fever, moist skin, warm to touch, and altered level of consciousness. As you are not familiar with the pt, you check the resident's history prior to admission. On the history the following is listed: CVA (Stroke), History of brief psychiatric disorder, CHF (congested heart failure), right hip arthroplasty (hip replacement), and DM (diabetes). What is likely affecting the resident? A) they are having a behavioral incident B) they have not been compliant on medication C) they don't have anything and hope it gets better D) resident may have sepsis from recent hip arthoplasty E) they have not had food after taking their insulin

D) resident may have sepsis from recent hip arthoplasty

A sample of milk is tested in a bacterial plate assay. A 1-ml of milk is diluted in a 1:10 dilution factor 3 times in a row. The 3rd diluted sample is cultured on agar and after incubation, the plate has 75 colony count. How many bacteria are there in the original milk sample? A. 75 cells/ml B. 750 cells/ml C. 7,500 cells/ml D. 75,000 cells/ml E. none of the above

D. 75,000 cells/ml

Biofilm is a collection of microbes living on a surface in a complex community. Since Biofilm usually requires slime layer producing species, what are some environmental factors that may allow for protection from? A. Desication B. Drugs and antibiotics C. Temperature D. All of the above E. None of the above

D. All of the above

What is a benefit of binary fission for reproduction? A. only one cell needed to reproduce B. daughter cell is exact copy C. generation time is relatively fast D. All of the above E. A&B only

D. All of the above

Generation time measures how long it takes a bacteria population to double in numbers. If a bacteria population has five cells and grew to 20 after an hour what is the generation time? Two hours One hours 15 minutes 30 minutes 40 minutes

30 minutes

Lvl 1 What is it called when something is used to remove pathogens from non-living surfaces? A) Disinfection. B) Antisepsis. C) Sensitization. D) Biocide. E) Bacteriostasis.

A) Disinfection.

What is the purpose of gut flora? A) gut flora makes vitamin K, folic acid, Riboflavin, and vitamin B12 B) gut flora acts as a defense against invading viruses C) your gut flora is a bioflim that covers your gut to protect you from the ph of your stomach acid D) it is a collection of bacteria that cannot escape E) none of the above

A) gut flora makes vitamin K, folic acid, Riboflavin, and vitamin B12 Good, but your gut flora doesn't live there TO make vitamin K, folic acid, etc. FOR YOU. It lives there in a symbiotic relationship WITH YOU and both sides benefit from this relationship.

What is the purpose for measuring the rates of microbial growth? Determine generation time Find efficacy of food preservation methods Access growth requirements To look at them underneath a microscope A, B, and C

A, B, and C

What is true about Superoxide Dismutase? Is a catalyst Creates oxygen-free environment Reduce superoxide into oxygen and hydrogen and peroxide Antioxidant in most cells except Lactobacilli A, C & D

A, C & D Good but technically speaking SOD is an antioxidant in any organism that can produce it. Lactobacillus sp. can produce SOD but because they lack catalase, they cannot completely remove hydrogen peroxide produced by SOD.

All of the following are "growth factors" except. A. Nucleotides B. Amino acids C. Vitamins D. Inorganic elements

D. Inorganic elements

There are four toxic forms of oxygen. Which one is used by human white blood cells to oxidize pathogens. A. Singlet oxygen B. Superoxide radical C. Peroxide anion D. Hydroxyl radical E. All of the above

A. Singlet oxygen

Organisms that utilize an inorganic source of carbon (CO2) as their sole source of barbon are called A. autotrophs B. Heterotrophs C. Chemotrophs D. Phototrophs E. Chemoautotrophs

A. autotrophs

What accurately describes the Stationary phase of microbial growth? A.The ratio of bacterial cell death to replication is about equal B.the bacteria are stationary C.The bacteria are dying at a faster rate D. The bacteria are undergoing binary fission at a slower rate E. stationary phase preceeds log phase

A.The ratio of bacterial cell death to replication is about equal

What factors do you have to consider when trying to find an effective treatment for microbes? Environment Time of exposure Biofilms Number of microbes All of the above

All of the above

Which of the following is a way to collect a microbial sample from a patient? Drawing blood using a needle Using a swab and rubbing it against the skin Cutting a piece of their issue Collecting a urine sample All of the above

All of the above

Which of the following is true about having a slime layer on biofilms? It helps keep desiccation Antibiotics have trouble reaching the cells It attracts other microbes. A and B All of the above

All of the above

Which of the following method(s) directly measure microbial growth? Plate Counts Filtration Most Probable Number Direct microscopic count All of the above

All of the above

What does penicillin do to the microbes it targets? Alternate the membrane permeability Damage proteins Damage to nucleic acids A and B All of the above

Alternate the membrane permeability

A employee working in a restaurant cuts her finger while washing a steak knife and inadvertently gets her blood on a countertop. What is the most appropriate terms for describing the antimicrobial treatment of the finger, knife, and countertop respectively? Disinfection, Antisepsis, Sanitization Antisepsis, Sanitization, Disinfection Sanitization, Disinfection, Antisepsis All of the above None of the above

Antisepsis, Sanitization, Disinfection

A patient is filling out a consent form for the __________ vaccine. However, they are allergic to eggs. This vaccine has egg preservative in it and should be avoided before consulting with their physician. . . . (Level 2) A) MMR B) Flu C) Hep A & B D) Varicella E) HPV

B) Flu

Lvl 2 Why is there no rise in the graph (Figure 6.20) at the Stationary Phase? A) All of the bacteria are inactive at this point. B) The growth rate and the death rate are equal so the numbers of bacteria are not changing. C) All of the bacteria got tired of reproducing and stopped. D) All of the bacteria are dying at the stationary phase. E) The graph does raise at the Stationary Phase.

B) The growth rate and the death rate are equal so the numbers of bacteria are not changing.

Sterilization means removing all microbial life. Is a test tube in the laboratories that has not yet been open considered sterile, and if so why or why not? A. It is not sterile because there are airborne microbes living inside. B. It is sterile because it has not been exposed to any air borne microbes or any microbes in the environment. C. It is not sterile because microbes are ubiquitous and everywhere regardless if the test tube has never been opened. D. It is sterile because of the oxygen within the test tube. E. None of the above

B. It is sterile because it has not been exposed to any air borne microbes or any microbes in the environment.

If an antimicrobial agent is bacteriostatic, A. complete killing of bacteria occurs with its use. B. bacteria will resume growth upon removal of the agent. C. no viable organisms remain after its use. D. it will kill only spores. E. it will kill bacteria and inhibit fungi.

B. bacteria will resume growth upon removal of the agent.

Dental plaque is made up of a complex community of numerous microorganisms. The cells in this community are able to communicate as well as share nutrients. What do we call this? A. slime layer B. biofilm C. binary fission D. cultivation E. none of the above

B. biofilm

An environment where the cell loses water due to being in a hypertonic solution is called? A. isotonic solution B. plasmolysis C. autoinducer D. hypotonic solution E. none of the above

B. plasmolysis but plasmolysis is the effect caused by a hypertonic environment, not the actual enviornment.

L1 what is the most common way a bacteria will reproduce? Budding Generation time Binary fission A and C All of the above

Binary fission

The destruction or killing of microbes refers to Biocide/germicide Aseptic Disinfection Sanitation None of the above

Biocide/germicide

The growth in turbidimetric measurement where the degree to which refractive rays of light is transmitted is normally expressed as. . . (level 1) A) cfu/mL B) cells/mL C) optical density D) mg/mL E) None of the above

C) optical density

A certain bacteria was inoculated on a 1-ml of TSB media with a starting count of 1,000 cells/ml. Then, it was added to 9-ml of fresh culture broth and this new culture was allowed to grow at the right conditions. If the generation time is 1 hour, how long would it take for this media to reach an estimated 6,400 cells/ml. Assume that there is no lag and stationary phases. A. 4.5 hrs B. 5 hrs C. 6 hrs D. 6.5 hrs E. 7 hrs

C. 6 hrs To clarify, what you meant to say is that the population was able to go right into the log phase of growth without delay.

The absence of significant contamination is known as what? A. Disinfection B. Antisepsis C. Asepsis D. Sepsis E. Sanitization

C. Asepsis

Antisepsis: a. Removing pathogens from surface b. Lowering microbial count on eating utensils C. Removing pathogens from living tissue d. Kills microbes e. Inhibiting, not killing, microbes

C. Removing pathogens from living tissue

You noticed that a culture broth tube was very turbid at the bottom of the tube but clear at the top of the tube. You can conclude that the A. broth is sterile. B. organism can tolerate oxygen. C. organism cannot produce superoxide dismutase and/or catalase. D. organism are aerobes. E. The organism has died.

C. organism cannot produce superoxide dismutase and/or catalase. This question requires that you specify the culture was grown in TGB media because regular broth media such as TSB does allow diffusion of oxygen throughout the media, thus organisms that don't have enzymes to detoxify ROS will still die.

What is the best way to avoid contamination by microbes in a hospital setting? A. sterilize the room B. practice bacteriostasis C. use aseptic surgery techniques D. A&C E. none of the above

C. use aseptic surgery techniques It is true though, that instruments and rooms are sterilized in hospitals.

Which of the following are true about mammalian pathogens ? A. They grow between 10 degrees centigrade and 40 degrees centigrade B. They are mesophiles C. They grow between pH 6.5 and 7.5 D. a, b and c E. a and b

D. a, b and c

Which of the following can be caused by reactive oxygen species (ROS) ? A. Damage of DNA B. Damage of proteins C. Oxidation of co-factors D. a, b and c E. a and b

D. a, b and c

What is the enzyme that detoxifies Hydrogen peroxide during aerobic respiration without forming O2? A. Superoxide mutalase B. Carotenoids C. Catalase D. peroxidase E. Lipase

D. peroxidase

How does a spectrophotometer measure contents of a microbial mixture in a test tube? A) A photo is taken of the microbes and you count how many microbes are in the picture. B) The microbes are strained from the broth and weighed. The weight can be calculated to an approximated number of microbes. C) A chemical is mixed into the test tube and the microbes can be separated from the broth. D) The machine runs through the liquid and counts how many microbes are in the broth. E) A light is directed through the test tube. Microbes in the broth of the test tube absorb some of the light while the rest of the light hits a sensor/detector. Through the transmittance, the amount of microbes can be predicted.

E) A light is directed through the test tube. Microbes in the broth of the test tube absorb some of the light while the rest of the light hits a sensor/detector. Through the transmittance, the amount of microbes can be predicted.

After growing two samples of E. coli and Salmonella, you measure the absorbance of both bacterias via which method? In addition, you find that E.coli has a light absorbency of 75% while salmonella has a light absorbency of 5%. Which method was used, and which bacteria has the most growth in sample. A) streak plate method/ Salmonella B) dilutions/ Salmonella C) Direct microscopic count/ E. coli D) Light spectrometry/ Salmonella E) Light spectrometry/ E. coli

E) Light spectrometry/ E. coli

Between the years of 1827-1912, doctor _____ began using _____ to reduce infection during surgery. A) Louis Pasteur/ enzymes B)Gregor Mendel/ oxidizing agents C)Joseph Lister/ listerine C)50 cent/ vodka E)none of the above

E)none of the above Good but we covered this topic in the beginning of the semester . . .

In prokaryotic reproduction why does a cell hit the stationary phase? A. exhaust nutrient supplies B. no space to continue reproduction C. death D. life cycle of cell complete E. A, B, and D

E. A, B, and D

Your job in the lab is to cultivate microbes. You know that you have set up all the standard cultivating conditions. Knowing that not all microbes grow under the standard conditions, you go about setting up the special condition's, which are? A. oxygen levels B. metabolic indicator C. pure culture D. essential nutrient E. A,B,and D

E. A,B,and D

Bacteria and Archaea exhibit greater metabolic diversity than any other group, and are considered members of A. Photoautotrophs B. Photoheterotrophs C. Chemoautotrophs D. Chemoheterotrophs E. All of the above

E. All of the above but we didn't really cover the difference between all of these groups in lecture

A cell wall controls the effects of osmosis. If a cell, affected by an antimicrobial agent, is dropped into a hypotonic solution, what would happen? A. Nothing, cell continues normal metabolism B. The cell membrane proteins or phospholipids get damaged C. Cellular contents leak in and out of the cytoplasmic membrane D. Cell bursts from taking in too much water E. B, C, and D

E. B, C, and D To clarify, cells in a hypotonic environment would take in to much water even it hasn't been treated with an antimicrobial agent. Also, not all antimicrobial agents affects the cell membrane.

Which is false regarding the physical effects of water on bacteria? A. Microorganisms require water to dissolve enzyme and nutrients and to act as reactant in many metabolic reactions. B. Obligate halophiles require high osmotic pressure to survive. C. Facultative halophile do not require but can tolerate salty environments. D. Obligate halophiles live on the bottom of sea, where the hydrostatic pressure is high. E. Obligate halophiles can survive at sea level where the pressure is not as high.

E. Obligate halophiles can survive at sea level where the pressure is not as high. but choices D and E aren't something we have talked about in class. :)

Which is not a benefit of Binary Fission? A.Only one parent is needed to reproduce. B. Rapid division. C. Daughter cells are clones of their parent cells. D. A lot of daughter cells are produced in a limited time. E. Protects against cell death.

E. Protects against cell death. To clarify, the clonal nature of daughter cells produced by binary fission isn't always a benefit.

If you were treating at an open wound, why would your first concern be to clean the area around it rather than directly treating the wound? A.anything placed on the wound would lead to the bloodstream and cause infection B. Treating the wound directly in it would damage the tissue and delay healing processes C. Both B and E* D. Our normal flora would'nt turn into opportunistic microbes if they spread to different parts of the body systems. E. autoinducer molecules are specifically meant to attract microbes to an area and create biofilm which is a suitable enviroment for bacterial growth, so it's best to swab around the wound to remove biofilm and bacteria rather than directly on the wound.

E. autoinducer molecules are specifically meant to attract microbes to an area and create biofilm which is a suitable enviroment for bacterial growth, so it's best to swab around the wound to remove biofilm and bacteria rather than directly on the wound.

what condition would most accurately describe "Turbidity" A.color B.speed C.phase of matter D. temperature E. cloudyness

E. cloudyness

In Evaluating disinfectants and antiseptics, different chemical methods are used for the control of microbial growth. Two common methods involve the use of Phenols and phenolics. These methods involve A: The disruption of proteins B: The disruption of Cell walls C: The Disruption of cell membranes D: A&B E:A&C

E:A&C

Which statement is false? Isotonic solution-solution concentration is equal inside and outside the cells Hypertonic solution-increase in salt or sugar inside the cells Hypertonic environments cause plasmolysis Obligate halophiles require high osmotic pressure Facultative halophiles tolerate high osmotic pressure

Hypertonic solution-increase in salt or sugar inside the cells

In the ________ phase bacteria are more sensitive to antibiotics. a. Stationary b. Log c. Death d. Lag e. Decline

Log

A scientist places a test tube containing bacterial culture into a spectrophotometer in order to determine which phase of growth is currently taking place. The spectrophotometer reading indicates a transmittance of 90%. After returning from running errands, the scientist finds the reading is now at 70% transmittance and still decreasing. What phase of bacterial growth is occurring? Death phase Lag phase Log phase Stationary phase Logarithmic decline phase

Log phase

A microbiologist discovers wants to find the microbial growth of a new bacteria he discovered in a sample of water he took from a lake. He first pours the sample into a flask with a permeable layer towards the top of the flask and counts the bacteria collected. What is the name of the method he performed? Direct Microscopic Count Turbidity Membrane filtration Dry Method Most Probable Number

Membrane filtration

Most bacteria prefer to live in an isotonic solution where the: Osmotic pressure is high Osmotic pressure is low Pressure is the same inside and outside A and C B and C

Pressure is the same inside and outside

Which method of measuring microbial growth is the best for a dense microbial population? Direct microscopic count Serial dilutions and viable plate count Membrane filtration Most probable number method All of the above

Serial dilutions and viable plate count

In medical field, all reusable instruments are always treated after using on each patient. What type of decontamination would it be? Disinfection Biocide Aseptic Sterilization Germicide

Sterilization

When looking at a cell, you noticed that the cell shriveled up. Why so? The cell was placed in a hypotonic solution which then causes the cell to lysis. The cell was placed in a hypertonic solution which then causes the cell to undergo plasmolysis. The cell was placed in an isotonic solution which then causes the cell to undergo plasmolysis. The cell was placed in a plasma membrane. The cell just finished phosphorylation.

The cell was placed in a hypertonic solution which then causes the cell to undergo plasmolysis. That would be true for eukaryotic cells without cell walls, but prokaryotic cells have cell walls and thus you wouldn't be able to detect plasmolysis under the microscope most of the times.

A scientist is getting ready to select an antimicrobial agent to test on bacteria X. What factors does the scientist need to consider when selecting an antimicrobial agent? That the antimicrobial agent is inexpensive That the antimicrobial agent is fast-acting That the antimicrobial agent is stable during storage That the antimicrobial agent is capable of controlling microbial growth, but yet is not harmful to humans. The ideal antimicrobial agent should have all of the above

The ideal antimicrobial agent should have all of the above

Pasteurization uses heat to destroy pathogens and reduce the number of spoilage microbes in food and beverages. After pasteurization, a scientist noticed the beverage did not maintain its shelf life. Why is that? There were microbes in the beverage that produce endospores Microbes were introduced during the process of pasteurization The pasteurization process did not kill all the microbes The microbes withstood pasteurization Microbes cant live after pasteurization, so it has to do with packaging.

There were microbes in the beverage that produce endospores

A surgical technique that prevent the contamination of wounds. a) asepsis b) sepsis c) sterilization d) none of the above e) all the above

a) asepsis but officially it's called aseptic technique.

A new drug is found to inhibit the production of most auto inducer molecules, what effect would you expect to result from taking this drug? a. Lack of dental plaque b. Poor digestion c. A weaker immune response d. Greater medical implant rejection e. More nasal mucus

a. Lack of dental plaque probably a reduction rather than a lack of dental plaques

A scientist successfully isolates two different types of bacteria and grows both under same conditions.After two hours the number of bacteria A grew to be 16 times the original amount. Bacteria B grew up to be 64 times the original amount after four hours of incubation. Which of the following is true? a. the generation time of bacteria A is 30 minutes; the generation time of bacteria B is 40 minutes. b. the generation time of bacteria A is 30 minutes; the generation time of bacteria B is 30 minutes. c. the generation time of bacteria A is 30 minutes. the generation time of bacteria B is 45 minutes. d. the generation time of both bacteria A and B is 30 minutes. e. none of the above.

a. the generation time of bacteria A is 30 minutes; the generation time of bacteria B is 40 minutes. but the generation time for bacteria B isn't 40 minutes . . . If bacteria B experienced a larger increase in population compared to bacteria A, then the generation time should be shorter than that of bacteria A, right?

You notice your bacteria is reproducing rapidly. You also realize they are the same size, what can you conclude? a. they are reproducing by binary fission b. they are "budding" c. both a & b d. none of the above e. not enough information

a. they are reproducing by binary fission

At 100,000 dilution and if you have 17 colony forming units per 1mL, what is the dilution factor CFU's per mL in a serial of dilutions. a. 7,000 CFU's/mL b. 1,700,000 CFU's/mL c. 70,000 CFU's/mL d. 700,000 CFU's/ml e. 17,000,000 CFU's/mL

b. 1,700,000 CFU's/mL but you meant to ask the concentration of the original culture and not the dilution factor, which was given in the question. :)

________________ is the time interval required for a cell to undergo binary fission, which can take up to _______ hours for a bacteria to double in numbers. a. Growth curve, 1 b. Generation time, 3 c. Log period, 2 d. Stationary period, 3 e. Exponential period, 5

b. Generation time, 3 not expecting you to know that it can take up to 3 hours to undergo cell division though. :)

A student uses listerine mouthwash to clean their mouth after eating spicy food. The mouthwash is best described as a(n): a. disinfectant b. antiseptic c. sterilizer d. antibiotic e. biocidal product

b. antiseptic

Which phase would you see an exponential growth in the generation time of microbial reproduction? a. lag phase b. log phase c. stationary phase d. death phase e. plateau phase

b. log phase To clarify, growth during the lag phase is technically exponential as well, but the low numbers make it less obvious compared to the log phase.

You Measure Microbial Growth where no incubation is required, staining is usually required, and you count the amount of microbes within several quadrants. What techniques is this? (Lvl 1) a. Most Probable Number b. Serial Dilutions c. Direct Microscopic Count d. Viable Plate Counts e. Trubidity of Liquid Culture

c. Direct Microscopic Count

Which method is not viable when measuring microbial growth? a. membrane filtatration b. serial dilutions c. direct microscopic count d. plate count e. all of the above

c. direct microscopic count To clarify, you CAN count living cells under the microscope, but we usually stain it first and thus the cells are dead by the time you count them.

What does sanitization do? a. remove pathogens from surfaces b. remove pathogens from living tissue c. lower microbialcounts on eating utensils d. all of the above e. none of the above

c. lower microbialcounts on eating utensils

We are looking to make a 1:100,000 solution for testing. What would be some drawbacks to doing a straight 1 to 100000 dilution? a. high chance of error b. large quantities of diluent c. large consumption of intermediate glassware d. A and B e. B and C

d. A and B

Helicobacter pylori is a bacteria associated with stomach ulcers. Knowing this what are some assumptions we can make about this bacteria? a. It is a microaerobe b. It creates a biofilm c. It is acidophilic d. A and B e. B and C

d. A and B Great Lv 3 question! H. pylori isn't an acidophile, but with the limited knowledge, it is reasonable to think that H. pylori is an acidophile. What would have made it clear is the fact that H. pylori colonizes the mucus layer that lines the stomach instead of the stomach cavity that holds the gastric juice.

Microbes from collected samples need to be isolated to obtain a pure culture. What technique is used and why is it important? a. Negative staining; it allows for a clear view of the microbe under the microscope b. Serial Dilution: each time the solution is diluted, the cells concentration becomes more usable c. Membrane Filtration: it separates a substance with the force applied d. Streak Plate: sample is streaked so the microbe can be identified and tested e. All of the above

d. Streak Plate: sample is streaked so the microbe can be identified and tested

The turbidity of a liquid culture is an indirect way of measuring microbial growth. What does it mean on the spectrophotometer if the percent of light transmitted is low? a. there is a high absorbance of light b. there is a low absorbance of light c. a high concentration of microbes d. a and c e. b and c

d. a and c

What is true about serial dilutions and viable plate count? a. requires mixing 1 mL of original solution with 9 mL sterile water to dilute the solution. b. one must use a plate with CFU of 30 to 300 colonies to estimate the original amount of bacteria that was present. c. By multiplying the CFU by10^2n (n stands for the number of times dilution was done) will give the EXACT number of bacterias present from the original solution.. d. both A and B. e. all of the above.

d. both A and B.

You were given an assignment to measure microbial growth by any direct method of choice. Which of the following would you use? a) Filtration b) Plate counts c) Turbidity d) Direct microscopic count e) a, b and d

e) a, b and d

The professor gives the students a tube with microbes in a broth. The students then shine a light through the tube and do a light reading producing a result of 57% Light Absorbent. The students then leave the broth for 3 hours and do another reading producing the result of 48% Light Absorbance. What stages was the growth at for both readings? (Lvl 2?) a. Lag Phase, Death Phase b. Death Phase, Log Phase c. Stationary Phase, Death Phase d. Log Phase Stationary Phase e. Log Phase, Death Phase

e. Log Phase, Death Phase but there isn't actually enough information in the question to know that the culture was at lag, log, or stationary phase when it produced a 57% light absorbance.

An obligate halophile requires low____ to grow. a. pH b. Pressure c. Salt d. B & C e. None of the above

e. None of the above

Antimicrobial agents should be... a. inexpensive b. fast-acting c. stable during storage d. effective only on microbes but harmless to hosts or humans. e. all of the above.

e. all of the above.

If you have leftover food for dinner and you plan to eat it later or the following day by putting it away in the refrigerator, you are inhibiting the growth of bacteria without destruction. What microbial control lingo is it? a. biocide/germicide b. sanitization c. asepsis d. antisepsis e. bacteriostasis

e. bacteriostasis And remember why we should let the food cool down completely before putting it in the frig . . .

If a student wants to dilute a broth of bacteria what should they do? a. start off with 9mL of broth b. add 1 mL to the 9 mL of broth c. Start of with 8 mL of broth d. add 2 mL of broth e. both a & b

e. both a & b Good but that is only if the student wants to do a serial dilution . . .

Which of the following is NOT a direct method to measure microbial growth? a.) direct microscopic count b.) filtration c.) standard plate count d.) most probable number (MPN) e.) metabolic activity

e.) metabolic activity

Some microbes can transform N2 (Nitrogen Gas) into usable compounds, this is achieved which process? a.) photosynthesis b.) anabolism c.) fermentation d.) nitrogen reduction e.) nitrogen fixation

e.) nitrogen fixation

Organisms that are likely to encountered in low-temperature food spoilage because they grow fairly well in refrigeration temperature are considered__________. a.) thermophiles b.) microphiles c.) peroxidase d. psychrophiles e.) psychotrophs

e.) psychotrophs