Microbiology Exam 2

Not very penetrating radiation. Easily stopped by interfering materials. Works by producing thymine dimers in DNA strands -Ionization radiation -microwaves -ultraviolet radiation

Ultraviolet radiation

Both humans cells and bacterial cells divide by mitosis. True or False

False

Cell division is triggered exclusively when cells attain a threshold mass True or False

False

Cells cannot begin a new round of replication until they have completed finished dividing. True or False

False

DNA helices is responsible for adding nucleotide to the growing end of the DNA True or False

False

The generation time of Mycobacterium tuberculosis is -30 minutes -33 hours -10 days -3 hours -12 hours

12 hours

Calculate how many generations it takes for a single bacterial cell to become 256 cells. -8 -6 -5 -7 -256

8

Plasmid DNA is transferred -In 100 bp fragments -as an RNA copy -In single-stranded form -In double-stranded form -via aquaporins in the cell membrane

In single-stranded form

Select the statements about ionizing radiation that are true. -It causes food to become toxic -It causes food to become radioactive -It can be used to sterilize medical equipment -It may cause changes the make food carcinogenic -It can be used to sterilize medications -It can be used to reduce spoilage organisms on food.

It can be used to sterilize medical equipment It can be used to sterilize medications It can be used to reduce spoilage organisms on food.

Heat applied to beverages to prevent spoilage and kill pathogens. High-temperature-short-time protocols include holding liquids at 72˚C for 15 seconds. Does not sterilize -steam under pressure -pasteurization -commercial canning

Pasteurization

Which enzyme is NOT involved in DNA replication? -gyrase -helicase -DNA polymerase -ligase -RNA polymerase

RNA polymerase

Environmental factors control microbial growth through their effect on enzyme activity. True or False

True

The F pilus is -a projection of the cell's cytoplasmic membrane -a modified microfilament that is used for movement -a polymer of peptidoglycan that binds to the recipient's cell wall -a protein appendage that attaches Gram-negative cells to surfaces -a protein appendage that attaches the two cells together

a protein appendage that attaches the two cells together

Plasmids are -able to replicate independently of the chromosome -small pieces of independently replicating linear DNA -small pieces of single stranded DNA or RNA -essential to the survival of all bacteria -Involved in the replication of all bacteria

able to replicate independently of the chromosome

some germicides may become less efficient when used in/on areas with organic matter -toxicity -storage and stability -cost and availability -activity in the presence of organic matter -compatibility with the material being treated

activity in the presence of organic matter

Which of the following are examples of growth factors? -starch -amino acids -phospholipids -cholesterol -vitamins -nucleotides -polysaccharides -water

amino acids vitamins nucleotides

The plasmic is mobilized for transfer when -It is glycosylated by the Golgi complex -DNA polymerase cleaves it at the origin of transfer -an endonuclease cleaves it at the origin of transfer -single-strand stabilizing proteins attach to it. -a helices unwinds the two strands

an endonuclease cleaves it at the origin of transfer

Select the correct statements about autoclaving. -autoclave tape is used to ensure that na object has been effectively sterilized -autoclaving is consistently effective in sterilizing Most objects -autoclaving was pioneered by Louis Pasteur and is used to preserve food. -autoclaving involves the use of both temperature and pressure -adding pressure to the autoclave increases the temperature of the steam in it. -biological indicators such as heat-resistant endospores are used to ensure that an autoclave is working properly -a tightly closed container can be effectively sterilized by autoclaving

autoclaving involves the use of both temperature and pressure adding pressure to the autoclave increases the temperature of the steam in it.

Most cultured bacteria tend to multiply by _____ -fragmentation -sexual reproduction -binary fusion -binary fission -budding

binary fission

Uses an autoclave called a retort to destroy the endospores of Clostridium botulinum. It will not destroy the endospores of some thermophiles -steam under pressure -pasteurization -commercial canning

commercial canning

some substances are negatively affected by treatment with some germicides (i.e. corrosives damaging metals/rubber). -toxicity -storage and stability -cost and availability -activity in the presence of organic matter -compatibility with the material being treated

compatibility with the material being treated

differential materials respond differently to control measures. Some may even be destroyed by certain methods, preventing their use. -Risk for infection -environmental conditions -type of microbe -number of organisms -composition of the item

composition of item

In addition to transformation, the other two forms of horizontal gene transfer are -Insertion and deletion -conjugation and transduction -translation and transduction -missense and nonsense -conjugation and nonsense

conjugation and transduction

the first step in conjugation is -the release of quorum signaling proteins by each cell -mobilization of the plasmid -contact between the do not and recipient -duplication of the plasmid and the chromosome -removal of the peptidoglycan cell wall

contact between the do not and recipient

some germicides are highly effective, but are rare and /or expensive -toxicity -storage and stability -cost and availability -activity in the presence of organic matter -compatibility with the material being treated

cost and availability

The structure that divides the bacterial cell in two is called the -cleavage septum -fission line -cell plate -cross septum -cleavage furrow

cross septum

due to nutrient depletion and waste accumulation, cells begin to die at an exponential rate -death phase -stationary phase -lag phase -exponential/log phase

death phase

Mechanical removal of most microbes from living or inanimate surfaces -sterilization -preservation -decontamination -disinfection

decomtamination

used to treat non-critical instruments such as stethoscopes -sterilant -high-level disinfectant -Intermediate-level disinfectants -low-level disinfectant

intermediate-level disinfectants

Which of the following are example of biofilms? -dental plaque -scum accumulating in toilet bowls -slipperiness on rocks in stream beds -capsule formation around Streptococcus pneumoniea -furry grayish-white growth on old bread or fruit

dental plaque scum accumulating on rocks in stream beds slipperiness on rocks in stream beds

Reduction of most microbial life on inanimate surfaces -sterilization -preservation -decontamination -disinfection

disinfection

dirt, grease, and bodily fluids in/on an area can interfere with control methods, as can temperature, pH, and even humidity levels. -Risk for infection -environmental conditions -type of microbe -number of organisms -composition of the item

environmental conditions

cells are actively growing, doubling the population with each generation -death phase, stationary phase -lag phase -exponential/log phase

exponential/log phase

which of the following chemical is/are suspected carcinogens?

formaldehyde ethylene oxide

F+ cells -lack a plasmid and are recipients in conjugation -lack a chromosome and are recipients in conjugation -have a plasmid and are donors in conjugation -lack a plasmid and are donors in conjugation -have a plasmid and are recipients in conjugation.

have a plasmid and are donors in conjugation

used to treat semi-critical instruments such as gastrointestinal endoscopes -sterilant -high-level disinfectant -Intermediate-level disinfectants -low-level disinfectant

high-level disinfectants

High energy radiation that directly destroys DNA and damages cytoplasmic membranes. It can also cause indirect damage by producing reactive oxygen species (ROS) -Ionization radiation -microwaves -ultraviolet radiation

ionization radiation

cells are not dividing but are synthesizing enzymes required for growth -death phase -stationary phase -lag phase -exponential/log phase

lag phase

Used to treat floors, furniture, walls and so on. -sterilant -high-level disinfectant -Intermediate-level disinfectants -low-level disinfectant

low-level disinfectant

doesn't affect microorganisms directly, but can generate heat in fluids which can indirectly kill microbes -Ionization radiation -microwaves -ultraviolet radiation

microwaves

It takes longer to kill a large number of microbes than a small number. -Risk for infection -environmental conditions -type of microbe -number of organisms -composition of the item

number or organisms

a recombinant organisms is -one that has undergone a mutation -one that has donated genes to another organism -one that contains genes from another organisms -one that has no fixed species designation -one that has both a chromosome and multiple plasmids

one that contains genes from another organisms

which can be used to make draining water safe?

ozone, halogens, metals

slows microbial growth but does not reduce the number of existing microbes -sterilization -preservation -decontamination -disinfection

preservation

Cells must _____ their DNA prior to cell division -denature -replicate -translate -hydrolyze -transcribe

replicate

If you find that a particular plasmid has an R factor, the bacteria that has it will be -able to recycle nitrogenous waste into nitrates -able to use oil as carbon source -resistant to certain antibiotics -moving with a rotating axial filament

resistant to certain antibiotics

items that may come into direct contact with body tissues are more likely to cause serious infections if contaminated -Risk for infection -environmental conditions -type of microbe -number of organisms -composition of the item

risk for infection

The FtsZ protein is needed too form the _______ -ribosomes -replicated DNA -septum -mitochondria -All of these

septum

The F pilus binds to -lipopolysaccharide on the Gram-negative envelope -techoic acid in the cell wall of the recipient -specific receptors on the cell wall of the recipient -endocytic vesicles on the recipient plasma membrane -polysaccharides on the recipient's capsule

specific receptors on the cell wall of the recipient

With nutrients depleted, total number of viable cells remains constant, with some dying while other multiply -death phase -stationary phase -lag phase -exponential/log phase

stationary phase

Requires use of an autoclave. To sterilize, temperature must reach 121°C for a minimum of 15 minutes. -steam under pressure -pasteurization -commercial canning

steam under pressure

used to treat heat-sensitive critical instruments such as scalpels -sterilant -high-level disinfectant -Intermediate-level disinfectants -low-level disinfectant

sterilant

Destruction of all microbial life -sterilization -preservation -decontamination -disinfection

sterilization

All germicides are somewhat harmful to human and the environment. this parameter identifies HOW harmful the chemical is. -toxicity -storage and stability -cost and availability -activity in the presence of organic matter -compatibility with the material being treated

storage

some germicides may lose efficiently over time, or may be required in very large amount that would make them impractical for frequent applications -toxicity -storage and stability -cost and availability -activity in the presence of organic matter -compatibility with the material being treated

storage and stability

The F plasmid encodes for -the F pilus -antibiotic resistance -a polysaccharide capsule -an origin of replication -receptors on the cell surface

the F pilus

After the transfer of the F plasmid is complete -F+ cells becomes antibiotic sensitive -the F+ cell expresses an R factor -the F- cell becomes F+ -the F+ cell becomes F- -the F-cell becomes HfR

the F- cell becomes F+

The energy source for contraction of the FtsZ ring during cell division comes from ________ -the hydrolysis of ATP -the hydrolysis of gyrase -the hydrolysis of GTP -the synthesis of GAP

the hydrolysis of GTP

The main advantage for bacteria that have the ability to carry out conjugation and other forms of genetic exchange is that -they can protect their genetic material from heat, radiation, and chemicals -they can form biofilms more easily -they can increase the size of their chromosome -they produce much more quickly -they become genetically diverse

they become genetically diverse

select the reasons sugar or salt can be used for food preservation.

they may cause plasmolysis they dehydrate the bacterial cells they create a hypertonic environment, unfavorable for growth

Certain microbes are highly resistant to killing methods (e.g. endospores). -Risk for infection -environmental conditions -type of microbe -number of organisms -composition of the item

type of microbe