BIO 220 Review for exam 2

Which of the following heavy metals are still used in germicidal preparations?

Mercury Silver

Select which of the following are drawbacks to the use of metals in antimicrobial control methods.

Microbes develop resistance to these metals. They can be very toxic to human cells as well as microbial cells.

Which two of the following statements regarding heterotrophs are true?

Monosaccharides are generally good carbon sources for heterotrophs. Large organic molecules (like starch, a polymer of glucose) must be digested before absorption

A tube of clear nutrient solution ______ as microbes grow in it.

becomes turbid

Bacteria reproduce by

binary fission

A term referring to a condition free of pathogenic microorganisms, or a procedure or process designed to prevent entry of infectious agents, is

asepsis

An organism that uses inorganic CO2 as its carbon source is a(n)

autotroph

Microbes that use photosynthesis to derive organic compounds from CO2 are classified as _____, while microbes that gain their carbon in an organic form are classified as _____

autotrophs/heterotrophs

An agent that will inhibit the growth of bacteria is described as _____ whereas _____ agent will kill bacteria.

bacteristatic ;bactericidal

Sanitization, also called ______is the mechanical removal of most microbes from an animate or inanimate surface.

decontamination

Alcohol is used in which of the following applications?

degermination of skin

Chlorine compounds typically kill microbes by:

denaturing enzymes

Iodine compounds typically kill microbes by:

denaturing proteins

Chlorhexidine typically kills microbes by:

denaturing proteins. disrupting the cell wall. disrupting the cell membrane.

A virucide _____ viruses

destroys

The movement of atoms or molecules from an area of high concentration to an area of lower concentration is called

diffusion

because they can be toxic or harmful to human and other animal tissues, are normally only used on inanimate objects.

disinfectants

Boiling water can be an effective means of _____ in the clinic and home.

disinfection sanitization

Phenolics typically kill microbes by:

disrupting the cell membrane. disrupting the cell wall. denaturing metabolic enzymes.

A combination of iodine and an organic carrier (such as alcohol) that serves as a moderate-level disinfectant and antiseptic is a(n)

iodophor

Radiation that consists of short-wave electromagnetic rays (such as X rays), that cause ejection of electrons from target molecules and the creation of ions, is

ionizing radiation

Sterilization of the skin:

is highly dangerous and impractical

In commensalism, one partner benefits and the other partner

is neither helped nor harmed

Cellular growth

is stimulated by nutrients and environmental factors

The solute concentration in the environment is equal to the solute concentration within the cell under _____ conditions

isotonic

Which type of condition occurs when there are equal solute concentrations inside and outside of the cell?

isotonic

All bacteria can be divided by their energy sources as ______ or ______.

phototrophs; chemotrophs

Heat, radiation, and ultrasonic waves are physical _____ methods for controlling microorganisms.

physical

Some microbes produce ______ to protect themselves against damaging electromagnetic radiation.

pigments

During conjugation, the two bacterial cells are connected by the conjugative

pili

Bacterial cells placed in a solution where the concentration of solute within the cytoplasm is less than that of the extracellular solution would undergo

plasmolysis

If it encounters an environment that has far more solutes outside the cell compared to inside the cell, a bacterium will lose water by osmosis. This process is also called

plasmolysis

Which of the following is a type of mutation that affects only a single base pair in DNA?

point

Although they do have some drawbacks, heavy metals are used for:

preservatives. antiseptics. topical germicides.

RNA polymerase binds to the DNA region to initiate transcription.

promoter

Ultraviolet radiation induces ______, abnormal linkages between _____

pyrimidine dimers; adjacent bases on the same DNA strand

Aqueous solutions of ethyl or isopropyl alcohol are commonly used as antiseptics and disinfectants because they

quickly kill vegetative bacteria and fungi are relatively non-toxic are relatively inexpensive

Energy emitted from atomic activities and dispersed at high velocity through matter or space is called

radiation

The transfer of genes from donor to recipient in microorganisms, where the recipient strain shows a change in genetic makeup at the end, is referred to as

recombination

The main effect of cold treatment is to _____ the activity of microbes.

reduce

An obligate aerobe:

requires oxygen for survival

Prions are _____

resistant to heat and chemicals

Which cellular structure is involved in translation?

ribosome

The synthesis of proteins, or translation, occurs in structures known as

ribosomes

Which of the following describes the main function of the cell membrane?

selective barrier

Growth of microorganisms in the blood or other tissues is called

sepsis

True or false: Drinking water and utensils are reliably sanitized or disinfected by boiling water. True false question.

true

True or false: Halogens are microbicidal and can be sporicidal with longer exposure times.

true

True or false: Hypochlorites are probably the most extensively used of all chlorine compounds; however, chloramines are effective alternatives in treating water supplies.

true

True or false: Quats are rated for only low-level disinfection in the clinical setting.

true

True or false: The halogens are a group of nonmetallic elements with antimicrobial applications, including bromine, iodine, chlorine and fluorine. True false question.

true

True or false: The primary targets of microbial control are microorganisms that cause infection or spoilage.

true

True or false: Ultraviolet radiation is most lethal to microbes in wavelengths from 240 nm to 280 nm.

true

True or false: Weak tinctures of heavy metals may be used as antiseptics on intact skin.

true

The term that describes the appearance of a cloudy broth culture is _____

turbid

The term that describes the appearance of a cloudy broth culture is

turbidity

The four general cellular targets of antimicrobial agents are the cell _____, the cell _____, nucleic acid synthesis, and proteins.

wall; membrane

As the most extensively used chlorine compounds, hypochlorites are used for

wound treatment and skin cleansing food equipment sanitation swimming pool treatments

The uptake of free DNA by competent bacterial cells occurs during bacterial

Transformation

Which gene transfer method involves the uptake of free DNA by competent bacterial cells?

Transformation

A sequence of three consecutive nucleotide bases in DNA that encodes an amino acid is a(n) _____?

Triplet

Which term describes a sequence of three nucleotides that code for an amino acid in DNA?

Triplet

True or false: A bacterial cell described as competent can accept soluble DNA from the surrounding environment. True false question.

True

True or false: An agent's effect on cells is known as its mode of action.

True

True or false: DNA replication must occur prior to cell division to ensure that each new cell has a complete set of DNA chromosome(s).

True

True or false: Halogens and alcohols are examples of chemical agents used to control microbes.

True

True or false: The expression of the genotype creates traits referred to as the phenotype.

True

Prions are very resistant to chemicals and inactivation by _____, including autoclaving.

heat

An organism that must obtain its carbon in an organic form is called a(n)

heterotroph

Which organism relies upon organic compounds for its carbon and energy needs?

heterotroph

Which element plays a key role in maintaining the pH of cells?

hydrogen

Iodine compounds disrupt the native state of proteins by interfering with

hydrogen and disulfide bonding

The use of sugar or salt to preserve food creates a(n) _____ environment for the bacteria in the foods.

hypertonic

If the solute concentration of the surrounding solution is lower than that of the cell's internal environment, the solution is described as

hypotonic

An anaerobe grows best:

in the absence of oxygen

Flaming the loop in a microbiology laboratory is an example of using _____ for microbial control.

incineration

Which of the following should be considered when initially choosing a method of microbial control?

- Is it cost and labor-efficient - Is sterilization needed - Can it withstand physical or chemical treatments - Is the item reusable or disposable - Is it safe - Will it penetrate effectively

Antimicrobial solutions with water as the solvent are called _____, whereas antimicrobial solutions with alcohol or water-alcohol mixtures as the solvent are called _____

Aqueous; tinctures

The root that is used to indicate the killing of microorganisms is

-cide

How many replication forks are formed from opening a section of a circular DNA molecule during replication?

2

The percentage of oxygen in Earth's atmosphere is about

20%

If a DNA molecule contains 15% adenine nucleotides, what percent of cytosine does it contain?

35%

Moist heat is: Dry heat is:

60*C to 135*C 160*C to Several thousand *C

Most bacterial plasmids carry an origin of replication and at most ______ genes.

A few hundred

Which two of the following statements regarding eukaryotic transcription and RNA processing are correct?

A series of adenosines is added to the mRNA. Splicing to remove introns occurs in the nucleus.

Which describes a plasmid?

A small circular piece of DNA that replicates its nonessential genes independently of the chromosome.

Which of the following are examples of chemical agents used to control microbes?

Alcohols Aldehydes Oxidizers Heavy metals Phenolic compounds

If a cell is in a solution that is hypotonic relative to the cytoplasm, how will water move?

into the cell by osmosis

Which test is a method of detecting mutagenic and potentially carcinogenic agents based upon the genetic alteration of nutritionally defective bacteria?

Ames

Detection of mutagenic and potentially carcinogenic agents based upon the genetic alteration of nutritionally defective bacteria is called the _____ test.

Ames test

During translation elongation, peptide bonds form between

Amino Acids

Which is the main event of translation elongation?

Amino acids are joined by peptide bonds

Triclosan is a(n) Blank______ that has been banned for consumer use.

phenolic

The genes of which microorganism(s) are arranged as operons?

Bacteria

Phase variation is when bacteria turn on or off a set off genes, which leads to obvious changes in their

phenotype

Which is true regarding adenine and guanine?

Both are Purines

Which of the following are desirable qualities in a germicide?

Broad-spectrum microbial action Solubility in a solvent Penetrating ability Rapid action

Which of the following acronyms is used to describe the collection of elements which compose 96% the dry weight of a cell?

CHNOPS

True or false: The parent strands in a DNA molecule are used as templates to synthesize complementary strands of DNA.

True

A discrete cellular structure composed of a neatly packaged DNA molecule is

Chromosome

A critical concern for the food packaging industry is the elimination of endospores of

Clostridium botulinum

Horizontal gene exchange via a cellular bridge in bacteria is called

Conjugation

During conjugation, the donor cell generally retains a copy of the genetic material being transferred. This is termed a ______ process.

Conservative

According to the rules of complementary base pairing, the nitrogenous base _____ forms hydrogen bonds with guanine. (Spell out the full name of the base.)

Cytosine

Nonionizing radiation causes the formation of abnormal bonds within _____ leading to mutations

DNA

Which enzyme adds nucleotides to a growing DNA strand?

DNA Polymerase

What is the central dogma hypothesis of genetics?

DNA encodes RNA which encodes protein

Which is the main enzyme in elongation of a DNA strand during replication?

DNA polymerase

The enzymes that function in DNA replication.

DNA polymerase Helicase Ligase

How is phenol used in microbial control?

Disinfection of drains Treatment of cesspools Disinfection of animal quarters

Incineration is a good method of microbial control in which two instances?

Disposal of medical waste Flaming the loop in a microbiology laboratory

Ensuring that the DNA code will be maintained during cell growth and cell _____ is one of the two essential effects of the structure of DNA.

Division

Select the statement that most accurately reflects the use of heat as an antimicrobial agent.

Dry heat methods exert their effect by dehydrating cells.

Which is true regarding DNA replication?

Each new DNA helix contains one parent strand and one newly synthesized strand.

Which items can be sanitized by boiling water prior to safe, acceptable use?

Eating utensils Drinking water Bedding and clothing

Which three key features of the active transport process are shown in this diagram?

Energy in the form of ATP is required. A specific membrane protein is used as a transporter. Nutrients are transported against their concentration gradient, from low to high concentration.

True or False: Eukaryotic chromosomes are composed of DNA and RNA

False

True or False: Within a nucleotide, the phosphate group is linked to the 3' carbon of the pentose sugar

False

True or false: A cell with an integrated F factor transmits its genes at lower frequency than does a cell with a free plasmid in the cytoplasm.

False

True or false: In bacterial conjugation, all F+ donor cells are high frequency recombinant (Hfr) cells

False

True or false: Plasmids are insertion sequences that can lead to changes in genotype within a cell or between cells.

False

True or false: Routine skin antisepsis often is completed using phenolics.

False

True or false: Operons are found in fungi and helminths.

False; only bacteria and archaea

What is the main effect of nonionizing radiation on cellular targets?

Formation of abnormal DNA linkages

A segment of DNA that contains the necessary code to make a protein or RNA is called

Gene

A sequence of DNA nucleotides that codes for one functional protein or RNA is called a

Gene

The complete set of chromosomes and genes in an organism is referred to as the

Genome

Which term represents all of the genetic information within a cell?

Genome

The shortest length of time required to kill all test microbes at a specified temperature is referred to as the thermal

death time

Which is a purine?

Guanine

Aerobes have which two of the following characteristics?

Have enzymes that can detoxify harmful oxygen products Can use gaseous oxygen in their metabolism

In DNA replication, _____ unwinds (unzips) the double helix, primase synthesizes the short RNA primer, and DNA _____ adds nucleotides to the new chain.

Helicase/Topoisomerase; polymerase

In bacterial conjugation, which type of donor has the fertility factor integrated into the chromosome?

Hfr

When organisms acquire genes which did not come directly from parent organisms it is referred to as _____ gene transfer

Horizontal

Select which of the following are examples of dry heat methods of control.

Hot air Incineration

About 96% of the dry cell weight is composed of which elements?

Hydrogen Nitrogen Carbon Sulfur Phosphorous Oxygen

Which two of the following are transport functions of the cell membrane?

Import nutrients Export waste materials

How does RNA differ from DNA in bacteria and eukaryotes?

In RNA, uracil replaces thymine RNA is single-stranded

What are the effects of adding pressure to water in an autoclave?

Increases temperature of steam Increases boiling point of water

The lac operon in E. coli regulates the metabolism of

Lactose

Which is FALSE regarding binary fission?

Like meiosis in eukaryotes, it specifically produces daughter cells with genetic variation.

Which two of the following statements regarding plasmids are true?

Many bacteria carry plasmids in addition to their chromosome. Plasmids may contain genes that specify resistance to antibiotics.

Choose the condition under which glutaraldehyde is a good choice for sterilizing materials.

Materials that can be damaged by heat

A nitrogen-containing structure found in DNA and RNA that provides the basis for the genetic code is a

Nitrogenous Base

Building blocks of DNA, called _____, contain the same sugar and phosphate, but different nitrogenous bases.

Nucleotides

Delicate medical instruments such as endoscopes become highly contaminated with human tissues and fluids, and should be sterilized in a low-temperature cabinet using which sterilants?

Peracetic acid Hydrogen peroxide

True or false: The structure of DNA is essential for providing variety since the order of nucleotides is responsible for the unique qualities of each organism.

True

When a cell is actively growing, the arg operon is ______, and arginine is ______.

On; actively synthesized

The control locus of the lac operon contains a region of DNA that acts as an on/off switch for transcription called a(n) Blank

Operator

The heat treatment of perishable liquids to destroy heat-sensitive vegetative cells and prevent infection and spoilage is called

Pasteurization

Areas of the genome containing multiple genes which contribute to a new trait for the organism that increases its ability to cause disease are termed

Pathogenicity Islands

Which of the following are areas of the genome where multiple genes exist that are coordinated to create a new trait, making the bacterium more pathogenic?

Pathogenicity islands

True or false: The two primary iodine preparations are free iodine and iodophors.

True

The process of bacteria turning on or off a group of genes that changes their phenotype in a heritable manner is called

Phase Variation

The process of bacteria turning on or off a group of genes that changes their phenotype in a heritable manner is called _____

Phase Variation

The characteristics resulting from the interaction of the particular genetic makeup of an organism and the environment is the _____ of that organism

Phenotype

Within a nucleotide, the ____ group is linked to the 5' carbon of the pentose sugar

Phosphate

A small circular segment of DNA found in the cytoplasm of bacteria that is capable of independent replication and usually contains nonessential genes is called a(n)

Plasmid

During replication,_____ synthesizes primer sequences.

Primase

Which enzyme synthesizes primer sequences during replication initiation?

Primase

The element hydrogen is important for which of the following functions?

Producing weak and easily reversible bonds between molecules Maintaining pH Providing free energy in oxidation-reduction reactions of cell respiration

RNA polymerase binds to the DNA _____ region to initiate transcription.

Promoter

RNA polymerase binds to which region of DNA to begin transcription?

Promoter

The control locus of the lac operon is composed of the ______, a region of DNA that is recognized by RNA polymerase.

Promoter

Choose the four general cellular targets of antimicrobial agents.

Protein function Nucleic acid synthesis The cell wall The cell membrane

The union of two adjacent pyrimidines on the same DNA strand, brought about by exposure to ultraviolet light, is called

Pyrimidine Dimer

Plasmids that encode resistance to a variety of antimicrobial agents and heavy metals are called ______ plasmids or factors.

R

Genes encoding resistance to antimicrobial drugs can spread to different strains, species, and even genera, most commonly through conjugative transfer of

R Plasmids

The antibiotic rifamycin, used to treat tuberculosis, binds and inhibits the activity of

RNA ploymerase

The enzyme that transcribes DNA into RNA is

RNA polymerase

Which enzyme transcribes DNA into RNA?

RNA polymerase

Complete the following sentence with the correct series of transcriptional terms: ______ binds the ______ to begin ______.

RNA polymerase; DNA promoter region; transcription

During transcription, RNA polymerase synthesizes ______ from a(n) ______ template.

RNA; DNA

Which term refers to the transfer of genes from donor to recipient microorganisms?

Recombination

During DNA ____ the DNA is duplicated prior to binary fission.

Replication

The Y-shaped point on a replicating DNA molecule where the DNA polymerase is synthesizing new strands of DNA is the _____ fork.

Replication

Which are goals of pasteurization?

Retention of liquid qualities Reduction of microbial load

During DNA replication the newly made double helices are composed of one parent template and one newly synthesized strand and therefore the replication is considered _____?

Semiconservative

Which two of the following are examples of degermation?

Surgical handscrub Wound cleansing

Which of the following are effects of ionizing radiation on food products?

Small decreases in thiamine Changes in texture of some foods Killing of bacterial pathogens

Which two of the following statements are accurate regarding heterotrophs?

Some heterotrophs are restricted to just a few carbon substrates. Amino acids may be a good carbon source for a heterotroph.

A particular part of the host genome is included in the virus during ______ transduction.

Specialized

Mutations that occur because of errors in DNA replication are termed

Spontaneous

An agent that can destroy bacterial endospores is a

Sterilant

Which three of the following are common uses for glutaraldehyde?

Sterilize respiratory therapy equipment Sterilize kidney dialysis machines Sterilize dental equipment

What factors must be considered in order to adequately sterilize using heat?

Temperature Length of exposure

In a DNA molecule the parent strands are used as a(n) _____ to synthesize a complementary strand of DNA.

Template

What did Griffith's experiment using Streptococcus pneumoniae demonstrate?

That DNA released from a dead cell can be transferred to a live cell.

Which two statements regarding eukaryotic transcription and RNA processing are correct?

The exon-intron junction is recognized by a spliceosome. Transcription occurs before splicing.

How do an Hfr cell and an F+ cell differ?

The plasmid is integrated into the chromosome of an Hfr cell but not in an F+ cell.

Vertical Gene Transfer

Transfer of DNA from parent organisms during reproduction

The different types of nucleotides in DNA contain

The same sugar and phosphate, but different nitrogenous bases

Which is true of a hypotonic condition?

There is a higher solute concentration inside the cell than outside the cell.

You release a small drop of methylene blue dye into a beaker of water. What happens to the molecules of blue dye?

They move from the region of high concentration to regions of low concentration.

The process of copying DNA into messenger RNA is

Transcription

Which recombination method involves transfer of DNA via bacteriophages?

Transduction

Horizontal gene transfer

Transfer of DNA from a source other than the parent organisms

A type of nonionizing radiation that is routinely used to disinfect air and the surfaces of solid objects is

Ultraviolet (UV)

Unlike DNA, RNA contains the nitrogenous base

Uracil

Facultative anaerobes have which three of the following characteristics?

Utilizes aerobic respiration when oxygen is present Can grow in the absence of oxygen Do not require oxygen for their metabolism

Iodine compounds are commonly used for:

antisepsis of skin. treatment of skin wounds. disinfection of medical equipment.

is the destruction of most microbes using chemicals on a living surface such as the skin.

antiseptic

Aqueous solutions of ethyl or isopropyl alcohol are commonly used as antiseptics and disinfectants because they _____

are relatively inexpensive are relatively non-toxic quickly kill vegetative bacteria and fungi

In parasitism, one partner is helped and the other is

harmed

Most microorganisms live and grow in habitats between pH 6 and pH 8 because enzymes and other cellular substances are damaged by solutions with pH values below 7, called strong,_____ and solutions with more extreme pH values above 7, called strong _____.

acids; bases

The arginine operon is "on" when the cell is

actively growing

A microorganism that can use gaseous oxygen in its metabolism and possesses enzymes needed to process toxic oxygen products is a(n) _____ organism

aerobe

A sterile object is free of _____

all viable microorganisms and viruses

Cellular growth is characterized by:

an increase in cellular components. an increase in cell number. an increase in cell size.

A particular microorganism produces a substance that kills another microorganism in its environment. This is an example of

antagonism

An agent that kills fungal spores, hyphae and yeasts is called a

anti fungal

If an agent disrupts the cell wall, the cell is likely to experience:

death by lysis

Sodium hypochlorite is also known as

bleach

One approach to controlling bacteria and fungi is by _____ the synthesis of the cell wall.

blocking

Moist heat occurs in the forms of

boiling water steam

A germicide with a(n)_____ spectrum is most desirable.

broad

A microbe's nutritional type (e.g., chemoheterotroph) is determined by its sources of

carbon and energy

The genes of the lac operon in E. coli encode enzymes that

catabolize lactose

The enzyme that converts hydrogen peroxide, derived from a harmful by-product of oxygen, to water and oxygen is

catalase

The primary targets of microbial control are microorganisms that

cause infection cause food spoilage

The bacterial cell structure specialized for transport is the

cell membrane

Antiseptics are ______ agents applied to the skin to inhibit vegetative bacterial cells.

chemical

Which term describes organisms which acquire their energy from chemical compounds?

chemotrophs

Gaseous and liquid _____ compounds are mostly used for large-scale water disinfection.

chlorine

A type of symbiotic relationship between two organisms in which one species derives benefit without harming the other is called

commensalism

Bacterial cells that can accept soluble DNA from the surrounding environment are referred to as

competent

Donor and recipient bacterial cells are connected by the pilus during

conjugation

In which of the following genetic recombination processes in bacteria is DNA transported between bacterial cells when a cellular bridge is formed?

conjugation

The three methods of gene transfer in bacteria are

conjugation transformation transduction

DNA repair enzymes have _____ as their substrate

damaged DNA

The permanent termination of a particular organism's vital processes is called _____. Special qualifications are often needed to define and delineate this phenomenon in microbes.

death

Alcohols are effective against:

enveloped viruses. fungal cells. resistant bacteria.

Chlorine compounds usually kill microbes by denaturing _____ and thereby disrupting metabolic reaction

enzymes

DNA damage can be resolved by

enzymes

A spontaneous mutation arises in DNA from

errors in DNA replication

The gas that is most effective for killing endospores is _____

ethylene oxide

the gas ______ Is used to sterilize prepackaged medical devices, syringes, and Petri dishes.

ethylene oxide

A microbe that does not require oxygen for its metabolism, and is capable of growth in the absence of it, is called a(n)

facultative anaerobe

True or false: A process that completely removes or destroys all viable microorganisms, including viruses, from an object or habitat is referred to as disinfection.

false

True or false: Halogens are only microbistatic.

false

True or false: In bacterial conjugation, all F+ donor cells are high frequency recombinant (Hfr) cells.

false

True or false: Iodine compounds are commonly used for household cleaning.

false

True or false: Ionizing radiation is not an effective method of controlling microbes in food products.

false

True or false: Mutations are always harmful to cells.

false

True or false: Nonphotosynthetic microbes are neither helped nor harmed by exposure to visible light.

false

True or false: Only a few microorganisms are killed by iodine even if proper concentrations and exposure times are used.

false

True or false: Phenolics typically kill microbes by inhibiting protein synthesis.

false

True or false: Sepsis is a term referring to a condition free of pathogenic microorganisms or a procedure or process designed to prevent entry of infectious agents.

false

True or false: Sterilization methods are often used to prepare the human body for surgical procedures.

false

True or false: There are several degrees of sterility, based on the destruction of endospores.

false

In filtration, a fluid is strained through a filter with openings large enough for the ______ to pass through but too small for ______ to pass through.

fluid; microorganisms

The two primary iodine preparations are

free; iodophors

Random fragments of host DNA are taken up by the bacteriophage during assembly in Blank______ transduction.

generalized

In binary fission, the doubling time of a particular microbial species is also known as its

generation time

Which term describes the length of time of a microbial species needs to divide?

generation time

The dosage of radiation is measured in

grays

A graphical representation of the change in population size over time is a(n)

growth curve

A group of nonmetallic elements with antimicrobial applications, including bromine, iodine, chlorine, and fluorine, are called _____

halogens

Chlorhexidine solutions are commonly used for:

hand scrubs. mucus membrane irrigation. prepping skin for surgery.

Which two types of macromolecules make up the majority of the cell membrane in microorganisms?

lipids and proteins

The two types of macromolecules that make up the majority of the cell membrane in microorganisms are _____ and _____

lipids; proteins

Quaternary ammonium compounds are considered to be _____ -level disinfectants.

low

In active transport, molecules are moving across the membrane from an area of ______ concentration to an area of ______ concentration.

low; high

If an agent disrupts the cell wall, the cell becomes fragile and is destroyed by

lysis

Which of the following is NOT a way that a chemical control agent damages a cell wall?

making it more permeable

The component responsible for preventing the loss of important molecules, and stopping the entry of damaging substances, is the cell

membrane

An aerobic bacterium that requires oxygen at a concentration less than that in the atmosphere is a(n

microaerophile

Lower temperatures are usually Blank______; higher temperatures are usually Blank______

microbistatic; microbicidal

The lowest temperature that permits a microbe's continued growth and metabolism is called the _____ temperature.

minimum

An agent's adverse effect on cells is known as its

mode of action

In terms of using heat as an agent of microbial control _____, heat methods operate at lower temperatures and shorter exposure time versus _____ heat methods.

moist; dry

A permanent inheritable alteration in the DNA sequence of a cell is a(n)

mutation

A small number of _____ are considered beneficial in that they provide the cell with a useful change in structure or physiology. Antibiotic resistance in bacteria is an example.

mutations

Which of the following is the most common gas on Earth?

nitrogen

Antagonism is a ______ association occurring when members of a community _____

nonsymbiotic; compete with each other

The process by which nutrients are acquired from the environment, and used in cellular activities such as metabolism and growth, is called

nutrition

_____ is the acquisition of chemical substances by organisms for use as an energy source or as building blocks of cellular structures.

nutrition

An organism that requires oxygen for survival is called a(n) _____ or strictly aerobic organism.

obligate

sterilization is:

only necessary for certain groups of microbes. generally reserved for inanimate objects.

disinfection destroys

only vegetative bacterial cells

A microorganism that lives in a habitat with a high solute concentration is a(n)

osmophile

Which term is used exclusively to describe water's movement across a selectively permeable membrane?

osmosis

Which is the pH range for habitats in which most microorganisms can survive and grow?

pH 6 to pH 8

A relationship between two organisms where the host is harmed and the colonizer benefits is called

parasitism

A quantitative comparison of the effectiveness of a chemical disinfectant to that of phenol is the ______ ______.

phenol coefficient

Plasmolysis of bacteria in foods occurs when high concentrations of salt or sugar are added to the foods creating a(n) ____ environment

smooth; pores

An osmophile lives in a habitat with a high ______ concentration.

solute

What type of agent specifically destroys bacterial endospores?

sporicide

A process that completely destroys or removes all viable microorganisms, including viruses, from an object or habitat, is referred to as

sterilization

The destruction of all microbial life is called _____, whereas _____destroys most microbial life, thus reducing contamination on inanimate surfaces.

sterilization; disenfection

Because of concerns about botulism, commercial food canneries must ______ food items.

sterilize

An agent that disrupts the lipid bilayer of membranes, and alters the membrane's permeability, is a(n)

surfactant

Cells in a pure water environment will

take in water, swell, and burst

Conjugation is a conservative process, meaning that

the donor retains a copy of the genetic material being transferred

The antibiotic rifamycin can be used to treat tuberculosis because

the drug is more active against bacterial RNA polymerase than the human enzyme

Disinfectants are normally only used on inanimate objects because:

the high concentrations needed are harmful to living tissues.

The number of bacterial cells is plotted as a function of _____ to show the _____ of the population.

time; growth

RNA polymerase binds the DNA promoter to initiate

transcription

The method of DNA recombination in bacteria that involves the transfer of DNA via bacteriophages is called

transduction

Griffith's experiment using Streptococcus pneumoniae demonstrated the process of

transformation

Insertion sequences that can lead to changes in genotype within a cell or between cells are called "jumping genes" or

transposons

True or false: A mutation is an alteration in the DNA sequence or content of a cell that is passed on when the cell divides.

true

True or false: A surfactant is an agent that disrupts the lipid bilayer of a membrane, creating leaky spots that alter the membrane's permeability.

true

True or false: Chlorhexidine typically kills microbes by disrupting the cell membrane or denaturing proteins.

true

True or false: Death involves the permanent termination of a particular organism's vital processes.

true