mastering micro HOMEWORK questions CH.4,5,6

The reagents crystal violet, iodine, and safranin are all associated with which of the following staining procedures? the endospore stain the flagella stain the acid-fast stain the Gram stain

D

Blood agar is an example of which of the following? a differential medium and a complex medium a differential medium a complex medium and a selective medium a complex medium

A

If it takes 2 hours for a population of bacteria to grow from 100 cells to 1600 cells, what is the generation time of this bacterial species? 15 minutes 20 minutes 30 minutes 40 minutes

C

A microbe is growing on Sabouraud dextrose agar, which has a slightly acidic pH. Which of the following is this microbe likely to be? an acid-fast bacterium a fungus a Gram-positive bacterium a Gram-negative bacterium

B

Any molecule that serves as an electron acceptor will be __________. catabolized reduced phosphorylated oxidized

B

Microbiologists study parasitic worms because __________. they usually contain bacteria and other microbes they are microscopic as adults they cause diseases that are diagnosed by finding microscopic eggs in clinical specimens they were not studied by early microbiologists

C

A colony-forming unit is a __________. commonly used isolation technique special type of growth medium single cell or group of related cells that gives rise to a colony tool used to collect clinical specimens

C

A thin film of microorganisms on a slide is called a __________. biofilm mordant smear stain

C

Sampling lake water for microscopic organisms is not as easy as it sounds when you want to both count and identify species. In a given water sample, your bacteria of choice can be rare or difficult to culture, particularly given the mixture of bacteria in a biofilm. Which of the following culture media would be best for growing fecal coliforms when they are relatively less abundant than other bacteria in the lake? anaerobic culture medium complex culture medium enrichment culture medium basic culture medium

C

Spallanzani's experiments concerning spontaneous generation were NOT universally accepted because __________. he did not give proper credit to Needham for his experiments he did not know which bacteria were growing in his flasks he eliminated air from his flasks by sealing them he did not heat his infusion flasks long enough

C

Whose experiments supported the existence of a "life force"? Pasteur Redi Needham Spallanzani

C

A microbiologist is using heat to drive the stain carbolfuchsin into a smear. Which of the following staining procedures is the microbiologist using? the flagella stain the capsule stain the Gram stain the acid-fast stain

D

A microorganism has the following characteristics: eukaryotic, multicellular, has cell walls, and grows in long filaments. What is its general classification? protozoan bacterium parasitic worm fungus

D

How many net ATPs can be made from one molecule of glucose in glycolysis? Six One Four Two

D

What did the work of Lister and Ehrlich have in common? They both examined the role of microbes in fermentation. They both demonstrated the importance of cleanliness in the prevention of disease. They both discovered the bacterial causes of important infectious diseases. They both explored the use of chemicals in the prevention and treatment of infectious diseases.

D

If you begin with six cells, how many cells would you have after three rounds of division? Twelve cells Nine cells Eighteen cells Twenty-four cells Forty-eight cells It is impossible to determine.

E

Which of the following terms is likely to describe optimal growing conditions for Streptococcus mutans? psychrotroph thermophiles halophile mesophile

Mesophile: Streptococcus mutans grows well at human body temperature.

Drag the labels onto the flowchart to indicate how the body uses food in cellular respiration. a) ATP is produced with the help of the electron transport chain. b) Fuel molecules are broken down further in glycolysis and the citric acid cycle (also called the Krebs cycle). c) Eating food provides fuel and building blocks for your body. d) After food is broken down in the digestive system, it is transported to cells via the circulatory system.

c d b a

Why is Daniel underweight? Daniel is not eating very much, because he likes scrambled eggs, which are high in fat. Daniel is not eating much, because it hurts to chew and swallow. Daniel is not eating much, because pudding is high in sugar. Daniel is not eating much, because candy is very filling.

Daniel is not eating much, because it hurts to chew and swallow. Dental caries are painful as are the swollen gums. His mouth hurts without adding the chewing action.

A chemoheterotroph obtains its energy from __________ and its carbon from __________ sources. redox reactions; organic light; inorganic light; organic redox reactions; inorganic

A

Cavities Gone Wild Five-year-old Daniel appears to be shy. He always looks at the floor, has no friends, never plays with the other children, and will rarely speak to adults, and when he does speak, it is difficult to understand his broken enunciation. His skinny frame and the dark circles under his eyes make him appear malnourished. Daniel cries frequently and misses many days of school. A speech specialist at school finds that only two of Daniel's teeth are healthy; all the others have rotted away to the gum line. The little guy is in constant pain and it hurts to chew. A doctor later determines that bacteria from the cavities in his mouth have entered his bloodstream and infected his heart, causing an irregular heartbeat and poor blood circulation. Which of the following is an example of a biofilm? bacteria growing in plaque bacteria growing on nutrient agar bacteria growing in nutrient broth bacteria present in the bloodstream

A

Microbial growth is at its maximum rate during which of the following phases of the microbial growth curve? log phase lag phase death phase stationary phase

A

What results when a single bacterium reproduces? Two genetically identical daughter cells One parent cell and a genetically identical daughter cell Two genetically unique daughter cells One parent cell and a genetically different cell

A

Which of the following is NOT a catabolic pathway or reaction? the conversion of glucose to starch the conversion of citric acid to oxaloacetic acid the conversion of pyruvic acid to acetyl-CoA the conversion of glucose to pyruvic acid

A

Why is visualization not sufficient to properly identify bacteria? Bacteria have a limited set of shapes and many unrelated bacteria share the same shape. Bacteria have a limited set of shapes. Identification is only needed in clinical specimens. Many unrelated bacteria can share the same shape. Not all bacteria can be seen with a light microscope.

A

What test result indicates that the unknown can utilize citrate as its sole carbon source? The medium turns blue. It turns the medium black. The culture becomes turbid. The medium turns pink.

A IT TURNS FROM GREEN TO BLUE IF YES

Put the following steps of bacterial replication in the correct order, starting from a parent cell. Cell elongation Septum formation Chromosome replication Separation of daughter cells 3, 1, 2, 4 3, 2, 1, 4 1, 4, 3, 2 2, 4, 3, 1 4, 3, 1, 2

A 3124

Which of the following molecules is broken down in cellular respiration, providing fuel for the cell? There is a ball-and-stick model of a molecule of glucose. The figure represents an ATP molecule. There is a model of a water molecule. There is a model of an oxygen molecule.

A GLUCOSE

Bacteria naturally prefer company instead of solitude for growth. Examples of this kind of communal growth pattern can be found everywhere, from surfaces of the teeth and the intestines, to the surface of a slimy rock in the lake, to the thick floc that clogs water pipes. These examples of communal bacterial growth are known by what name? infectious unit biofilm planktonic unit colony

B

Chlorophyll may be found in __________ of a prokaryotic cell. mitochondria infoldings of the plasma membrane the cytoplasm chloroplasts

B

Crenation can result from a change in which of the following? pH osmotic pressure temperature hydrostatic pressure

B

Glycolysis literally means energy producing. sugar splitting. Embden-Meyerhof. sugar producing.

B

How long does it take for the daughter cells to initiate or start the next round of replication? After the cells have matured fully. No time is required -- they are ready to divide immediately after DNA replication and separation of the daughter cells is complete if conditions are right. 20 minutes No time is needed -- the daughter cells cannot replicate further.

B

If you needed to look at the fine details of the interior of a virus, which microscope would you use? fluorescent microscope transmission electron microscope bright-field microscope scanning tunneling microscope

B

The most commonly used isolation technique in microbiology laboratories is the __________. viable plate count method streak-plate method pour-plate method enrichment culture

B

What carbon molecules remain at the end of glycolysis? Glyceraldehyde 3-phosphate (G3P) Pyruvic acid Dihydroxyacetone phosphate (DHAP) Glucose

B

What was Leeuwenhoek's contribution to the science of microbiology? He discovered some of the ways in which microbes can be transmitted between individuals. He was the first to observe live microorganisms through a microscope. He did experiments supporting the idea of spontaneous generation. He developed the vaccine for smallpox.

B

What would happen if the septum did not form during binary fission? The chromosome could not replicate. The parent cell would now have two copies of the chromosome. The daughter cells would not be genetically identical. Nothing; the septum is not required for binary fission.

B

Which of the following bacteria has an affinity for the heart valves? Bordetella pertussis Streptococcus mutans Staphylococcus aureus Bacillus subtilis

B

Which of the following does NOT happen above the maximum growth temperature of a microorganism? Lipids become too fluid. Membranes become rigid and fragile. Hydrogen bonds break. Proteins become denatured.

B

Which of the following groups of organisms belongs in the domain Eukarya? viruses protozoa archaea bacteria

B

Which of the following is NOT a step in bacterial cell division? Cell elongation Disappearance of nuclear envelope Replication of the genetic material Splitting apart of two new daughter cells

B

Which of the following represent the majority of pathogenic bacteria? thermophiles mesophiles hyperthermophiles psychrophiles

B

Which of the following statements about glycolysis is true? All cells perform glycolysis. Glycolysis is also called the Embden-Meyerhof pathway. Glycolysis produces glucose. Glycolysis is the main source of NADH in the cell.

B

You have isolated microorganisms that are green, photosynthetic, have a cell wall, and do NOT possess a nucleus. These organisms are __________. archaea bacteria fungi algae

B

[Comprehension]] Which of the following toxic forms of oxygen is IMPROPERLY paired with the detoxifying enzyme or molecule? peroxide anion: catalase hydroxyl radical: peroxidase superoxide radical: superoxide dismutase singlet oxygen: carotenoids

B

Which energy-rich molecule directly powers cell work? There is a ball-and-stick model of a molecule of glucose. The figure represents an ATP molecule. There is a model of a water molecule. There is a model of an oxygen molecule.

B ATP

Which nutrient is responsible for the development of cavities in teeth? sorbitol sucrose cholesterol albumin

B Sucrose; S. mutans organisms use sucrose to produce dextran and lactic acid, which directly contribute to dental caries

A scientist is using an objective lens with 40× magnification on his microscope. If the ocular lens magnifies 10×, what is the total magnification being used to visualize the specimen? 40× 50× 400× 4000×

C

All of the following individuals showed that cleanliness played a role in human disease EXCEPT __________. Semmelweis Nightingale Jenner Lister

C

Biochemical tests _________________. are visualized using microscopes are used to determine rate of growth are the main methods used to identify unknown bacteria are the most effective way to determine bacterial shape

C

Enzymes speed up the rate at which chemical reactions occur within a cell because the enzyme __________. raises the activation energy of the reaction removes the need for a cofactor lowers the activation energy of the reaction provides a heat source to supply energy to the reaction

C

Fermented foods such as sauerkraut or pickles are kept from spoiling by the effects of which of the following? hydrostatic pressure temperature pH low oxygen levels

C

Glyceraldehyde 3-phosphate (G3P) is an important intermediate molecule in the cell's metabolic pathways because __________. its six carbons become part of a variety of molecules in the cell it has a high-energy phosphate group like that of ATP it can be used in both catabolic and anabolic pathways it serves as an energy reserve molecule in the cell

C

How are the bacteria and the archaea different from all the other cellular microbes? They can move. They have cell walls. They have no nucleus. They reproduce asexually.

C

How does a noncompetitive inhibitor reduce an enzyme's activity? The inhibitor degrades the enzyme's normal substrate. The inhibitor degrades the enzyme. The inhibitor binds to the enzyme in a location other than the active site, changing the shape of the active site. The inhibitor inactivates the enzyme.

C

How is nevirapine used to treat HIV infections? It binds to the active site of HIV reverse transcriptase, decreasing that enzyme's activity. It increases the immune system's ability to detect the virus. It alters the active site of reverse transcriptase, decreasing that enzyme's activity. It decreases the virus's ability to find host cells.

C

How would the results be different if this organism was Salmonella? It would be a rod. It would not ferment lactose. It would produce hydrogen sulfide. It would not tolerate oxygen.

C

What enables the copied chromosomes to separate during binary fission? The mitotic spindle drives the separation. The nuclear membrane dissolves. The chromosomes are attached to different parts of cell membrane, which elongates and thus separates the chromosomes. The septum splits the replicated chromosomes.

C

What is the hallmark of dichotomous keys? They are open-ended questions. They only relate to biochemical processes of the cell. They consist of a series of paired statements, in which only one statement of each pair applies to a given organism. They only relate to the shape of the cell.

C

What would be the likely outcome if you increased the concentration of substrate for an enzyme in the presence of a noncompetitive inhibitor? A decrease in the amount of inhibitor would be observed. You would begin to see an increase in the enzyme's rate of activity. No change in enzyme activity would be observed. A decrease in the concentration of enzyme would be observed.

C

Which of the following compounds is necessary for transamination reactions? oxaloacetic acid amino acids pyridoxal phosphate aspartic acid

C

Which of the following is NOT a growing area of microbial study? communication within biofilms reducing antimicrobial resistance methods of disease transmission ultraminiature technology

C

Which step of binary fission is the reason for genetically identical daughter cells? Splitting of the two daughter cells Elongation of the cell Replication of the bacterial chromosome There are four new daughter cells that result from one parental cell

C

Why are enzymes important to biological systems? Enzymes are reuseable. Enzymes increase the energy barrier required of chemical reactions. Enzymes decrease the amount of activation energy required for chemical reactions to occur. Enzymes prevent unwanted chemical by-products from forming.

C

Why is the unknown in this example not Pseudomonas? It can tolerate oxygen. It is a rod-shaped cell. It ferments lactose. It is a Gram-negative cell.

C

Cultures of the Lake of the Ozarks water samples were grown on enrichment media for identification. However, these organisms are present to some degree in all samples. An important question from a clinical perspective is whether or not there is a significant increase in the fecal coliform populations that would put people's health at risk. If you were part of the team investigating this outbreak, how would you best enumerate the fecal coliform threat? direct microscopic counts plate count culture serial dilution count culture filtration count culture

D

How many questions are needed in this dichotomous key to determine if the unknown is Bacteroides? Five Two Four Three

D

In E. coli, the presence of isoleucine shuts down the enzymatic pathway that results in the synthesis of isoleucine. This is an example of __________. allosteric activation competitive inhibition denaturation feedback inhibition

D

Koch's work involving anthrax was significant because it was the first time __________. bacteria had been grown in a laboratory anthrax had been discovered in humans bacteria had been seen in a microscope a bacterium had been proven to cause a disease

D

Starting with three cells, how many cells would result from three rounds of replication? Six Nine Twelve Twenty-four Forty-eight Cannot be determined

D

Taxonomy consists of all of the following activities EXCEPT __________. grouping organisms nomenclature identification staining microorganisms

D

What is meant by the statement "Enzymes are biological catalysts"? Enzymes produce biological organisms. Enzymes produce products useful for biology. Enzymes are products of biological systems. Enzymes speed up the chemical reactions in living cells.

D

Which of the following is one-billionth of a meter? a micrometer a millimeter a centimeter a nanometer

D

Which of the following refers to the use of bacteria or other microbes to detoxify pollutants? biochemistry recombinant DNA technology biotechnology bioremediation

D

Which of the following techniques is most useful for measuring microbial reproduction when the density of a microbial population is very small? turbidity viable plate counts microscopic counts membrane filtration

D

Which of the following types of microscopes can magnify more than 2000×? a phase-contrast microscope a bright-field microscope a dark-field microscope a transmission electron microscope

D

Which type of medium is used to prevent the growth of certain microbes while allowing the growth of others? differential media reducing media enriched media selective media

D

Why do all enzymatic reactions need activation energy? Energy is needed for the enzyme to find its substrate. Energy is required by an enzyme so that it can be reused. Energy allows only the substrate to bind. Energy is required to disrupt a substrate's stable electron configuration.

D

Why is ATP required for glycolysis? ATP is used to convert PEP into pyruvic acid. ATP is used to reduce NAD+ to NADH. ATP is used to convert DHAP into G3P. ATP makes it easier to break apart glucose into two three-carbon molecules.

D

You might not consider the Midwest when someone mentions a beach trip, but the Lake of the Ozarks is a hotspot in the United States. Centrally located in the heart of Missouri, the lake is a great gathering place for Middle America vacations. It is one of the largest human-created lakes, containing roughly 600 billion gallons of fresh water, spanning approximately 61,000 acres and about 1100 miles of shoreline. Flow of the lake water is controlled by the Bagnell Dam. AmerenUE operates the dam for electrical production, in conjunction with the Army Corps of Engineers, which monitors the dam for spill-off, reservoir, and commerce. In a typical year, the lake system boasts 3.5 million tourists from Memorial Day to Labor Day, drawing in millions of dollars in vacations, tourism, boating, golf, hotels, and entertainment. During the summers of 2009 to 2011, things have been different at the Lake of the Ozarks. Bacterial growths have been "blossoming" in the water, which have the potential to cause disease. As a result, repeated closures have been necessary, and the beaches have been much quieter. The Missouri Department of Natural Resources (MODNR) routinely tests the waters for safety by counting fecal coliform bacteria. Fecal coliforms are a collection of microorganisms that live in large numbers in the intestines of warm-blooded animals (including humans). The best-known member of this group is Escherichia coli, but not all E. coli fecal coliform strains cause disease. However, E. coli can act as a marker of other microbial pathogen levels in the water. The Lake of the Ozarks is a human-made lake, so it collects runoff from coal strip-mining, fertilizers, resort wastewaters, and septic drainages. The average lake temperature is between 10∘C and 21∘C. Consider the physical requirements for growth and multiplication that would allow fecal coliforms to "blossom" in the Lake of the Ozarks. Which of the following would accurately describe these organisms? Check all that apply. Facultative halophiles Mesophiles Hyperthermophiles Psychrophiles Extremophiles

Facultative halophiles Mesophiles Psychrophiles

In addition to physical requirements, bacterial growth and multiplication also entails chemical requirements. Which of the following statements would accurately describe chemical requirements and conditions associated with growth in the Lake of the Ozarks environment? Select all of the following statements that are true regarding fecal coliforms in the Lake of the Ozarks. The lake environment will support the growth of facultative anaerobes. The lake environment will support only the growth of obligate anaerobes. Fecal coliforms will not need organic growth factors to grow in the lake environment. Fecal coliforms will likely contain enzymes to counteract toxic oxygen forms. Fecal coliforms will need to acquire trace elements for growth in the lake environment.

Fecal coliforms will need to acquire trace elements for growth in the lake environment. Fecal coliforms will likely contain enzymes to counteract toxic oxygen forms. The lake environment will support the growth of facultative anaerobes.

How is fermentation of lactose detected? The medium become turbid when exposed to air. The drop in pH turns the indicator dye yellow. The cells form a black precipitant. The acetoin produced turns the medium pink.

IF FERMENTATION OCCURS IT WILL TURN YELLOW AND LOWER PH. GAS BUBBLES MAY ALSO FORM B