Micro Test 2 study questions

Why is agar a useful substance in the microbiology lab? Agar dissolves in water at about 60°C. Solid agar melts at temperatures above 40°C. Agar does not solidify until it cools to about 40°C. Agar is a good source of nutrients for microbes

Agar does not solidify until it cools to about 40°C

Which of the following is both a selective and a differential medium? Sabouraud dextrose agar MacConkey agar blood agar nutrient broth

MacConkey agar

When artificial media are inadequate, what techniques are used to grow microbes for study? animal and cell cultures enriched media and sterile incubators development of microfilms on sterile coverslips use of natural substrates (for example, a raw potato)

animal and cell cultures

Which of the following eukaryotic cell wall types is INCORRECTLY matched? plants: cellulose animal cell: silica algae: agar fungi: chitin

animal cell: silica

All of the following statements are true of archaeal flagella EXCEPT: arachaeal flagella are 10-14 nm in diameter the proteins of the flagella differ from bacterial flagellin arachaeal flagella rotate from the flow of hydrogen ions across a membrane arachaeal flagella grow by adding subunits at the base—not the tip—of the flagella

arachaeal flagella rotate from the flow of hydrogen ions across a membrane

Hami are proteinaceous structures found in which of the following? eukaryotes bacteria archaea archaea and bacteria

archaea

ATP is expended in which of the following processes? a. diffusion b. group translocation c. active transport d. facilitated diffusion e. both active transport and group translocation

both active transport and group translocation

an acids dissociates in water to release

both anions and hydrogen ions

what bacterial cell structures plays an important role in the creation of biofilms?

both fimbriae and glycocalyces

Disulfide bridges are used in which level of protein structure? only secondary only tertiary only quaternary both tertiary and quaternary

both tertiary and quaternary

A(n) (indicator/base/buffer) is a substance that maintains the pH even when the amounts of acid and/or base are changed

buffer

a bacterial cell possesses a glycocalyx. it will be engulfed more quickly by defensive cells of the host. True or false

false

during osmosis, water crosses to the side of the membrane with a lower concentration. True of false

false

eukaryotic ribosomes are composed of 50s and 30s subunits. true or false

false

hydrogen bonds are stronger then covalent bonds. True or false

false

the only way to store bacterial cultures for short periods of time is to arrest their metabolism by freezing. true or false

false

Which of the following pairs of terms is an INCORRECT match? proteins: cytoskeleton nucleotides: ATP fats: peptidoglycan polysaccharides: cellulose

fats: peptidoglycan

All of the following are considered functional groups in organic chemistry EXCEPT __________. amino group hydroxyl group organic phosphate fatty acid

fatty acid

which of the following prokaryotic cells contain an outer membrane? a. gram negative bacteria only b. gram positive bacteria only c. both gram negative and gram positive bacteria d. archaea e. all prokaryotes

gram negative bacteria only

a periplasmic space is found in which of the following? a. gram negative cells only b. gram positive cells only c. both gram negative and gram positive cells d. neither gram negative nor gram positive cells

gram negative cells only

the accumulation of glucose 6-phosphate inside a bacterial cell via phosphorylation of glucose is an example of

group tanslocation

Which of the following is NOT considered a general type of chemical reaction found in living things? synthesis exchange hydrolysis decomposition

hydrolysis

a chemical reaction in which a water molecule is a reactant is known as a(n) (dehydration/hydrolysis) reaction

hydrolysis

the reverse of a dehydration synthesis reaction is a(n) ______ reaction

hydrolytic

Which of the following is the most reactive form of oxygen? peroxide anions singlet oxygen hydroxyl radicals superoxide radicals

hydroxyl radicals

Crenation, the shriveling of cells due to loss of water, occurs when cells are placed in what kind of solution? hypertonic hypotonic isotonic hypotonic or hypertonic

hypertonic

A solution with a pH of 7.0 would become the most acidic if one __________ the hydrogen ion concentration by a factor of __________. increased; 100 increased; 1000 decreased; 100 decreased; 1000

increased; 1000

Two atoms that have significantly different electronegativities can form a(n) __________. nonpolar covalent bond ionic or a polar covalent bond polar covalent bond ionic bond

ionic or a polar covalent bond

bacteria of the genus mycoplasma lack cell walls. What sort of environment do they require for survival?

isotonic

when the nucleus of an atom contains a constant number of protons but a variable number of neutrons, the atom is called a(n)

isotope

the (atoms/isotopes/stereoisomers) of an element vary in the number of neutrons in the necleus

isotopes

methane is classified as a compound becasue

it contains atoms of more than one element

pure water has a neutral pH becasue

it dissociates into equal numbers of hydrogen and hydroxyl ions

Which of the following could be an optimal pH for the growth of an acidophile? pH 3.0 pH 7.0 pH 8.5 pH 11.0

pH 3.0

all of the following are components of an amino acid EXCEPT a(n) a. R group b. carboxyl group c. amino group d. pentose group e. aplha carbon

pentose group

Which of the following components of the bacterial cell wall is found in varying amounts in both Gram-positive and Gram-negative cells? lipopolysaccharide peptidoglycan endotoxin teichoic acid

peptidoglycan

which of the following is NOT a type of lipid? a. steroids b. triglycerides c. peptidoglycan d. waxes

peptidoglycan

A cell that uses an organic carbon source and obtains energy from light would be called a __________. chemoautotroph photoautotroph photoheterotroph chemoheterotroph

photoheterotroph

a cell that uses an organic carbon source and obtains energy from light would be called a

photoheterotroph

Which of the following has NOT yet been discovered in the archaea? pili glycocalyces flagella fimbriae

pili

which of the following statements concerning pili is FALSE? a. pili are longer than fimbriae and flagella b. a bacterial cell will usually have only one or two pili c. pili facilitate the transfer of DNA among bacterial cells d. not all bacteria have pili e. pili are long, hollow tubules

pili are longer than fimbriae and flagella

eukaryotic cells use a process known as (pinocytosis/phagocytosis) to obtain liquids from their environment.

pinocytosis

DNA is composed of repeating units of sugars, phosphates, and nucleic acids. This is an example of a

polymer

What kind of biological molecule is a dipeptide? carbohydrate protein nucleic acid lipid

protein

which type of media is used to prevent the growth of certain microbes while allowing the growth of others?

selective media

MacConkey agar plates represent ______ medium

both a differential and a selective

if a cell counter slide is determined to have a mean number of 20 bacterial cells per square, the total number of bacteria per ml of culture would be __________. 1,000,000 25,000,000 50,000,000 100,000,000

25,000,000

If phosphorus has an atomic number of 15, how many electron shells does a phosphorus atom have? 1 2 3 4

3

A bacterial species has been determined to have a generation time of 30 minutes. If a microbiologist starts with an inoculum of 1000 cells/ml and wants to grow it to a culture of 1,000,000 cells/ml, approximately how long should the culture be incubated? 3.5 hours 5 hours 24 hours 100 hours

5 hours

The atomic number of the element carbon is 6; this means that it has __________. 6 protons in its nucleus 6 electrons in its nucleus 12 protons in its nucleus 3 protons and 3 neutrons in its nucleus

6 protons in the nucleus

what process requires a carrier protein?

Both facilitated diffusion and active transport

Which of the following would NOT be found in an inclusion? gases starch lipids DNA

DNA

Blood agar is an example of what?

Differential medium and a complex medium

Which of the following statements concerning hydrogen bonds is FALSE? Hydrogen bonds are a weak type of ionic bond. Hydrogen bonds are essential for life because they form strong connections between atoms. Hydrogen bonds result from forces created by polar covalent bonds. Hydrogen bonds are important for stabilizing the shapes of large molecules.

Hydrogen bonds are essential for life because they form strong connections between atoms.

Thiomargarita namibiensisis a notable microbe for which of the following reasons? It is a eukaryote with a prokaryotic-type flagellum. It is the largest prokaryotic microbe ever discovered. It is a eukaryotic cell that is the same size as E. coli. It is a prokaryote with a primitive nucleus.

It is the largest prokaryotic microbe ever discovered

The stereoisomers of amino acids and sugars most commonly used by organisms are __________. L amino acids and D sugars L amino acids and L sugars D amino acids and L sugars D amino acids and D sugars

L amino acids and D sugars

Which of the following statements concerning nitrogen is FALSE? Nitrogen is rarely a growth-limiting nutrient. Nitrogen is essential for the production of amino acids and nucleotide bases. All cells can recycle nitrogen from their nitrogen-containing molecules. Rhiozobium and Cyanobacteria are examples of a few bacteria that fix nitrogen.

Nitrogen is rarely a growth-limiting nutrient

what is a molecule, but NOT a compound?

O2

a chemoheterotroph obtains its energy from ________ and its carbon from ________ sources

Redox reactions; organic

Which of the following statements is NOT part of the biofilm formation process? The cells form a multicellular prokaryotic organism with organlike structures. Quorum sensing allows the microbes to respond to the density of nearby microbes. The matrix of the biofilm positions the cells to conserve digestive enzymes. Cells attach to a substrate and each other with an extracellular matrix

The cells form a multicellular prokaryotic organism with organlike structures

Which of the following statements explains why a triglyceride does NOT work as well as a phospholipid in forming cell membranes? Triglycerides contain a glycerol backbone, which gives rigidity to the cell membrane. Triglycerides lack a polar phosphate head that orients toward the water during self-assembly of a lipid bilayer. Triglycerides have three fatty acids to form the water-free interior of the lipid bilayer. Triglycerides contain three fatty acids, and therefore are partially soluble in water

Triglycerides lack a polar phosphate head that orients toward the water during self-assembly of a lipid bilayer.

Which of the following statements regarding clinical specimens is FALSE? Clinical specimens include saliva, feces, and blood. Universal precautions are observed in order to protect specimens from contamination. Clinical specimens are often transported in special media to help preserve them. Clinical specimens must be properly labeled

Universal precautions are observed in order to protect specimens from contamination.

Which of the following statements concerning the bacterial growth curve is FALSE? During the stationary phase, the number of dying cells equals the number of cells being produced. Under certain conditions, the log phase can be maintained indefinitely. Cells divide at a maximal rate during the log phase. When the death phase is reached, all cells in the culture have died.

When the death phase is reached, all cells in the culture have died

anna is conducting an experiment using a pH indicator that is red at low pH, green at neutral pH and purple at high pH. she starts with a green solution. When she add compouund X to her solution it turns purple. then she adds compound Z to the solution and it turns green. She adds more Z, the solution remains green. These observations suggest X is ______ and Z is ______

a base; a buffer

a microbe is growing on Sabouraud dextrose agar, which has a slightly acidic pH. What is the microbe most likely to be?

a fungus

what would contain teichoic acids?

a gram-positive cell wall

which of the following is a bond in which electrons are shared unequally? a. an ionic bond b. a polar covalent bond c. a nonpolar covalent bond d. either a polar or a nonpolar covalent bond

a polar covalent bond

Which of the following nitrogenous bases is found both in the cell's genetic material and in its energy-containing molecules? adenine guanine cytosine thymine

adenine

Which of the following groups of microbes does NOT undergo aerobic metabolism but can detoxify oxygen enough to live in its presence? obligate anaerobes microaerophiles facultative anaerobes aerotolerant anaerobes

aerotolerant anaerobes

All of the following are differences between bacterial flagella and eurkaryotic flagella EXCEPT that __________. bacterial flagella move in a wave motionwhereas eukaryotic flagella rotate 3600 eukaryotic flagella are within the cytoplasmic membrane, whereas prokaryotic flagella are not eukaryotic flagella are shafts composed of globular protein tubulin arranged to form microtubules, whereas prokaryotic flagella are composed of flagellin the filaments of the eukaryotic flagella are anchored in the cytoplasm by a basal body, wherease the prokaryotic flagella is anchored to the plasma membrane and cell wall by a basal body.

bacterial flagella move in a wave motionwhereas eukaryotic flagella rotate 3600

A microbe isolated from deep in the ocean could best be characterized as a __________. psychrophile mesophile barophile barophile and psychrophile

barophile and psychrophile

hydrogen bonds are found in all the following EXCEPT a. in the DNA double helix between nucleotides b. between the R groups of amino acids in proteins c. between phosphates in ATP d. between water molecules e. in alpha helices

between phosphates in ATP

a means of reproduction in which duplicate DNA molecules are separated by cell elongation, followed by formation of a septum to divide the cytoplasm is called

binary fission

_________ are complex communities of various types of microbes that adhere to surfaces

biofilms

A candle jar would be most useful in isolating which of the following? biofilms fastidious microbes capnophiles psychrophiles

capnophiles

a (capsule/slim layer/matrix) is a type of glycocalyx that is firmly attached to the cell

capsule

Which of the following pairs of terms is an INCORRECT match? defense: antibodies catalytic proteins: hormones that regulate cell metabolism transportation: membrane channels regulation: hormones

catalytic proteins: hormones that regulate cell metabolism

Plant cell walls are composed of which one of the following polysaccharides amylose glycogen amylopectin cellulose

cellulose

which of the following is classified as a nonmembranous organelle of eukaryotic cells? a. golgi body b. peroxisome c. endoplasmic reticulum d. mitochondrion e. centriole

centriole

organisms that require organic source of carbon and energy are called (chemoheterotrophs/ chemoautotrophs/auxotrophs)

chemoheterotrophs

short, hairlike structures used only by eukaryotic cells for movement are called

cilia

Which of the following types of media is INCORRECTLY paired? differential medium: different bacteria utilize nutrients in different ways defined medium: includes components for which the exact chemical composition is not known selective medium: favors the growth of some microbes and inhibits the growth of others complex medium: contains nutrients from partial digestion of yeasts, beef, soy, or milk

defined medium: includes components for which the exact chemical composition is not known

Blood agar plates are an example of ________ medium

differential

sucrose is an example of which of the following? a. a nucleotide b. a steroid c. a disaccharide e.a dipeptide

disaccharide

compounds that readily dissociate in water are

either polar or ionic

which of the following statements concerning endocytosis and exocytosis is TRUE? a. these processes occur in both prokaryotes and eukaryotes b. endocytosis produces a structure called a food vesicle c. waster products and secretions are exported form the cell during endocytosis d.phagocytosis is a type of endocytosis in which liquids are brought into the cell e. endocytosis is a form of passive transport, whereas exocytosis is a form of active transport

endocytosis produces a structure called a food vesicle

The structures that permit bacteria such as Treponema pallidum to "corkscrew" through a medium are called __________. flagellin polar flagella endoflagella flagella with a "9 + 2" microtubule arrangement

endoflagella

Which of the following membrane-bound organelles is INCORRECTLY paired with its primary function? nucleus: contains DNA and nucleoli mitochondrion: aerobic ATP production endoplasmic reticulum: exocytosis and secretion lysosome: breakdown of aged cell components

endoplasmic reticulum: exocytosis and secretion

if a eukaryotic cell suffers damage to its mitochondria, which of the following processes of life would be most immediately affected? a. reproduction b. growth c. responsiveness d. energy production

energy production

a fastidious organism might be grown on which of the following types of media? a. enriched media b. differential media c. selective media d. transport media e. reducing media

enriched media

The eukaryotic cytoskeleton is composed of all of the following EXCEPT __________. tubulin microfilament enzymes intermediate filaments

enzymes

Which of the following functional groups is NOT associated with amino acid structure? carboxyl sulfhydryl hydroxyl ester

ester

endocytosis and exocytosis are means of transport used by

eukaryotes

Passive transport of molecules across the cell membrane that requires specific channel proteins is called __________. osmosis facilitated diffusion group translocation endocytosis

facilitated diffusion

All of the following are drawbacks to the use of spectrophotometry in estimating microbial growth EXCEPT that __________. it will underestimate the true number of cells if they are not uniformly in suspension it cannot distinguish between live and dead cells it kills the organisms as they are being counted it cannot be used if there are fewer than one million cells per milliliter

it kills the organisms as they are being counted

when cells are metabolically active but not divining, they are in what phase?

lag phase

the correct sequence for the phases indicated by the letters A, B, C and D is

lag phase, log phase, stationary phase, death phase

Which of the following is NOT a component of peptidoglycan? amino acid lipid A NAM NAG

lipid A

lipid A is a component of

lipopolysaccharides

during which growth phase are bacteria more susceptible to antimicrobial drugs?

log phase

microbial growth is at its maximum rate during which phase of the microbial growth curve?

log phase

the preferred method for long term storage of bacteria is (freezing/refrigeration/lyophilization).

lyophilization

human pathogens are classified as

mesophiles

which of the following represent the majority of pathogenic bacteria? a. hyperthermophiles b. mesophiles c. thermophiles d. psychroplies

mesophiles

The endosymbiotic theory is one possible explanation for the origin of which of the following organelles? mitochondria Golgi body peroxisomes centriole

mitochondria

what organelle is responsible for producing most of the ATP in a eukaryotic cell?

mitochondria

which of the following is the most alkaine (basic) pH? a. pH 2.0 b. pH 7.0 c. pH 9.0 d. pH 13.0

pH 13.0

Which of the following is NOT a primary function of fimbriae? creation of biofilms adherence to surfaces movement toward chemicals or light enhancing a microbe's ability to cause disease

movement toward chemicals or light

what types of chemical bonds do carbon atoms generally NOT form?

neither ionic nor hydrogen bonds

what particle is found in the nucleus of an atom and has no electrical charge?

neutron

what subatomic particle does NOT have a charge

neutrons

the type(s) of bond produced when atoms share electrons equally is/are

nonpolar covalent bond

a monomer of a nucleic acid is called a (nucleoside/nucleotide/base)

nucleotide

a(n) _______ organism require(s) oxygen for growth

obligate aerobic

a microbe that grows only at the bottom of a tube of thioglycollate medium is probably a(n)

obligate anaerobe

The (optimum/range/minimum) growth temperature is the temperature at which an organism exhibits the highest growth rate.

optimum

nitrogen is a growth- limiting nutrient because cells need it to manufacture ___________

proteins and nucleotides

what is found is nucleic acids

purines

sodium thiogylcollate is associated with which of the following types of media? a. complex media b. differential media c. transport media d. selective media e. reducing media

reducing media

Which of the following functions of carbohydrates in cells is INCORRECTLY matched? starch or glycogen: long-term storage carbohydrate polymers: form cell walls ribose: cytoskeleton of bacterial cells monosaccharides: energy source for cells

ribose: cytoskeleton of bacterial cells

Which of the following is an organelle found in both prokaryotic and eukaryotic cells? ribosome centriole vacuole peroxisome

ribosome

which of the following is NOT a membranous organelle within a eukaryotic cell? a. ribosome b. nucleus c. endoplasmic reticulum d. chloroplast

ribosome

Which of the following organelles is present in both prokaryotic and eukaryotic cells? endoplasmic reticulum mitochondria ribosomes nucleus

ribosomes

Which of the following organelles is involved in producing and transporting proteins throughout the cell? rough endoplasmic reticulum smooth endoplasmic reticulum Golgi body ribosomes

rough endoplasmic reticulum

a(n) ______ is a compound that dissolves into anions and cations in water

salt

what is NOT a basic process of life?

sexual reproduction

a colony forming unit is a

single cell or group of related cells that gives rise to a colony

which of the following molecules would be expected to cross the cytoplasmic membrane rapidly and without the use of transport proteins? a. small hydrophobic molecules only b. small hydrophilic molecules only c. large molecules only d. ions only e. both ions and hydroplilic molecules

small hydrophobic molecules only

Which of the following kinds of molecules would be expected to cross the cytoplasmic membrane by diffusion alone? only electrically charged molecules only lipid-soluble molecules small, lipid-soluble molecules only small molecules

small, lipid-soluble molecules

the most commonly used isolation technique in microbiology laboratories is the

streak-plate method

In order to store living cells, a scientist must slow down metabolism by lowering temperature. Which of the following examples is INCORRECTLY paired? deep freezing: long term; -50°C to -95°C sub-zero freezing: long term; -10°C refrigeration: short periods of time lyophilization: freeze and remove water using an intense vacuum; ice sublimates

sub-zero freezing: long term; -10°C

the (peroxide/superoxide/hydroxyl) radical is formed during the incomplete reduction of O2 during electron transport in aerobes.

superoxide

Which of the following descriptions of protein structure is INCORRECTLY paired? primary structure: the length and sequence of amino acids secondary structure: alpha-helices or beta-pleated sheets tertiary structure: two or more polypeptide chains bond together through a disulfide bond quaternary structure: overall shape may be globular or fibrous

tertiary structure: two or more polypeptide chains bond together through a disulfide bond

a bacterial cell is placed in distilled water. Which of the following will happen? a. the cell will gain water b. the cell with shrink c. the cell will lose water d. there will be no net gain or loss of water in the cell

the cell will gain water

a clinical sample labeled as "sputum" was collected from

the lungs

what is a common trait of all lipids?

they are at least partially hydrophobic

Bacterial cultures go through lag phase because __________. they are synthesizing new enzymes in order to use nutrients in their medium they are gradually beginning to die the DNA and protein synthesis in the culture has not caught up with cell division they are being exposed to increasing amounts of their own waste products

they are synthesizing new enzymes in order to use nutrients in their medium

which of the following is NOT a characteristic of saturated fats? a. their fatty acids pack tightly together b. they are found in animals c. they contain at least on double bond d. they are usually solid at room temp e. they are a form of stored energy

they contain at least on double bond

organisms use carbhydrates in all of the following ways EXCEPT a. as a building block of DNA and RNA molecules b. as a short- term energy source c. to keep membrane flexible at low temps d. as a long- term energy source e. as a component of cell walls

to keep membrane flexible at low temps

a molecule composed of carbon and hydrogen is a compound. True or false

true

formation of a biofilm may contribute to bacteria's ability to cause disease. true or false

true

one of the products of dehydration synthesis reactions is water. true or false

true

All of the following are direct methods of measuring microbial growth EXCEPT __________. a Coulter counter membrane filtration viable plate counts turbidity

turbidity

in a hypotonic environment, the vacuole of the plant cell enlarges and pushes the cytoplasm against the cell wall. Which organelles are most likely able to store the extra water?

vacuoles

the presence of a cell (wall/membrane) enables bacterial and plant cells to resist the effects of hypotonic solutions

wall

Water is important for life for all of the following reasons EXCEPT that __________. water can participate in many cellular reactions water does not absorb heat energy water remains a liquid over a wide range of temperatures water has enough surface tension to form a layer on the surface of cells

water does not absorb heat energy