Microbiology UNH BMS 503 Final

In which of the following domains do we not find microorganisms?

A. Eukarya

B. Bacteria

C. Archaea

D. Microorganisms are found in all of the above domains

Microorganisms are found in all of the above domains

identify the proper nomenclature for the following microbe.

Streptococcus Pyogenes

S. Pyogenes

Streptococcus pyogenes

Streptococcus p.

Streptococcus pyogenes

Metabolism is:

All of the biochemical reactions taking place in an organism

The antibiotic Penicillin binds to the active site of one of the enzymes involved in the synthesis of the cell wall and permanently inactivates the enzyme. How would you define this type of inhibitor?

Competitive inhibitor

You are studying a bacterium that grows in very low nutrient aqueous environments. The microbe expresses a periplasmic binding protein to bind specific nutrients, which delivers them to a transport protein. Then hydrolyzes ATP in order to move the nutrients into the cell. Which type of transport is described here?

ABC transport system

The peptidoglycan layer of the bacterial cell wall is made up of

chains of alternating sugars with peptide linkages

In Gram-Negative bacteria, the extracellular composition consists of

a plasma membrane, a periplasmic space with a small peptidoglycan layer, and an outer membrane containing Lipopolysaccharide

the bacterial pilus can carry out all of the following functions, except

A. aid in attachment to surface

B. detect the presence of endospores

C. A type of movement described as twitching motility

D. mediate the transfer of genetic material

B. detect the presence of endospores

Exergonic vs endergonic

exergonic releases energy= -G (reactant > products)

endergonic gains energy= +G (reactants< products)

What would happen to the reaction in the energy diagram (exergonic) if an enzyme were added?

the reaction would progress faster

You have isolated a bacterium that you believe to be the causative agent of a new disease in frogs. How would you test the second of Koch's postulates?

grow a pure culture of the bacterium outside the frog

What type of microscopy is utilized to observe the cytoplasmic structure within a bacterial cell?

transmission electron microscope

bacterial cell wall synthesis occurs during the ____ of the bacterial cell cycle

B period

A bacterial capsule of polysaccharides that form a slippery mucous layer, this may inhibit

phagocytic killing by host cells

Which one of the following reinforces and stiffens membranes in bacteria and is analogous to cholesterol in a eukaryotic membrane?

Hopanoids

Staphylococcus aureus is known to cause both skin and upper respiratory tract infections. What does its name imply about its cellular morphology?

a spherical shape that grows in clusters

Which of the following is NOT common to all microbial cells?

Cell wall

You have disovered a new spiral shaped microorganism approximately 1um in diameter, with a single circular chromosome and chemically complex cell wall

most likely a prokaryote

During the process of Binary Fission, what is the purpose of FtsZ protein?

to find the center of the parent cell and split it into two daughter cells

You are studying the motility of Vibrio cholera. using flagellar stain, you observe bent-rod shaped cells with a single flagellum. The type of flagella arrangement is termed:

Monotrichous

gram positive cell wall

peptidoglycan layer, cell membrane, Lipoteichoic acid in periplasmic space

gram negative cell wall

Single, thin sheet of peptidoglycan, 1 - 3 nm thick.

Somewhat rigid structure

Thinness gives gram-negative bacteria greater flexibility and sensitivity to lysis

Blood agar plates (BAP) are enriched with sheep red blood cells. Both gram positive and gram negative organisms will grow on BAP and those that have the capacity to lyse RBCs will have a halo of clearing around the colonies. BAP is an example of:

differential media

Cyanide is a poison which prevents ATP production via aerobic respiration, leading to eventual death. Cyanide binds to an allosteric site on cytochrome c oxidase changing the shape of its active site and preventing cytochrome c oxidase from binding its substrate. Cyanide is an example of:

a non competitive inhibitor

In E coli, the LacY membrane channel uses the proton motive force to move a molecule of Lactose and one H+ into the cell from the environment. How would you describe this type of transport?

Symporter using simple transport

Which of the following is not a function of the cell membrane?

A. the cell membrane acts as a permeability barrier

B. the cell membrane acts as anchor for proteins involved in cellular processes

C. the cell membrane allows for the production of a proton gradient (H+)

D. the cell membrane drives protein synthesis

D. the cell membrane drives protein synthesis

Which of the following is true of anabolic reactions in a cell?

A. they may release energy form fuel sources to drive ATP synthesis

B. they may require energy to drive ATP synthesis

C. they may require energy in the form of ATP

D. they may release energy in the form of ATP

C. they may require energy in the form of ATP

Which mechanism(s) allow the bacterial chromosome to fit within the confines of the cell?

the bacterial chromosome is bound by looping proteins and supercoiled

What is the biological function of endospores?

Endospores allow for bacteria to survive starvation and/or harsh environments

During the decline/death phase of a batch culture the number of viable cells is _____ the number of non viable cells

less than

Which of the following features is not common to all bacterial cells?

A. growth

B. metabolism

C. motility

D. evolution

C. Motility

Isolucene binds an allosteric site on enzyme 1 in the pathway, inhibiting its activity and ultimately reducing the amount of Isolucene the cell produces. Isolucene is _____ in this biosynthetic pathway.

feedback inhibitor

Which of these groups are considered tp be microbes, but NOT considered to be cells?

Viruses

Some species of Synechocystis will use twitching motility to oritent themselves toward red and green light, but away from blue light. This is an example of:

phototaxis

Flagella allow bacterial cells to achieve directed movement using rotational motor proteins embedded in the cellular envelope. What drives the motor proteins?

proton motive force

When growing bacterial organisms in culture, which of the following may influence growth rate?

A. availability of nutrients

B. build up of waste products

C. temperature

D. any of these can influence growth rate

D. any of these can influence growth rate

What is the purpose of Bactoprenol?

to serve as a carrier to transport the new cell wall components across the membrane

The germ theory of disease refers to:

the theory that some human diseases are caused by microorganisms that have gained access to the human body

Why is it possible for E coli cells to have a doubling time less than 20 minutes?

they begin synthesizing DNA for the next generation prior to completing the first round of replication

Which of the following indicates how bacteria and viruses typically compare in size?

bacteria are much larger than viruses

Being small has its advantages, which of the following is true of prokaryotic cells?

A. they have a greater surface to volume ration than larger cells

B. they support greater nutrient exchange per unit volume than larger cells

C. they grow faster than larger cells

D. all of the above

D. all of the above

Griffith's experiment from 1928 determined that nonvirulent cells could be mixed with heat-killed virulent cells and be transformed into virulent cells that generated a capsule. how is this transformation explained?

the nonvirulent cells acquired the DNA that encoded for the enzymes necessary to generate a capsule from the heat killed cells

Which term refers to proteins that extend across the plasma membrane from one side to the other?

transmembrane proteins

the reaction that breaks down ATP to form ADP and inorganic phosphate is classified as:

exergonic

microbes with flagella are motile, how is their movement described?

runs in a straight line and tumbles to change direction

Chemotrophs obtain their energy from which of the following?

organic and inorganic chemical reactions

which groups of microbes contain the highest percentage of pathogens?

Viruses

The proton motive force, generated by the pumping of protons from the cytoplasm to the periplasmic space creates:

both an electrical gradient and a chemical gradient

_____ destroys all viable organisms, including viruses and endospores

sterilization

if a chemical is reduced in a chemical reaction that chemical ____ electrons

gains

filtrations is used to sterilize air and liquids that might be destroyed by heat. What determines the organisms removed by filtrations?

the size of the pores in the filter

ATP is a high energy molecule. In which parts of the molecule is the energy held?

in the triphosphate tail

What is the role of DnaA during bacterial chromosome replication?

Binding of DnaA allows DNA strand separation at oriC initiating DNA replication

chromosome replication in bacteria does not require which of the following:

Dna polymerase I

Dna polymerase III

Hexokinase

Helicase

hexokinase

the gene dnaE is an essential gene in E coli that encodes the alpha subunit of DNA polymerase III. Where would you expect to see the dnaE gene in E coli?

the chromosome

DNA replication, transcription, and translation all share the following three steps:

initiation, elongation, termination

Bacteria can generate a proton gradient and use it to power all of the following except

flagellar rotation

membrane transport

ATP synthesis

fermentation

fermentation

Which of the following components of Cellular Respiration harnesses the greatest amount of energy directly from the fuel source?

Citric Acid Cycle

Weak acids, like vinegar, inhibit bacterial growth and can be used to preserve foods because they:

collapse the electro-chemical gradient of H+

Glycolysis has an energy investment phase that uses ______ and an energy generation phase that synthesizes a total of ______

2 ATP; 4 ATP and 2 NADH

Which of the following would not be used as a fuel source for anaerobic respiration?

Fe3+

NH4+

NaCl

H2S

NaCl

A _____ electrochemical gradient is used to power ATP synthase in some bacteria, in lieu of protons

Na+

You are studying Bacillus subtilis, a chemoorganotroph. This bacterium:

generates ATP using oxidation or organic compounds

segments of DNA that can move from one molecule of DNA to a different DNA molecule are called:

transposable elements

you are testing a new antibiotic Slayericillin, you treat three separate cultures of E coli with either distilled water (control), tetracycline, or Slayericillin. The results of your experiment are shown. Slayericillin is a:

bactericidal drug

In the absence of a terminal electron acceptor, chemoorganotrophic bacteria will:

utilize fermentation to generate ATP via glycolysis

A photosynthetic microbe that contains PSI, but not PSII, would be expected to generate which of the following products from the light-dependent reactions of photosynthesis?

NADPH

DNA replication requires PriA, also known as primase, to create a _____ primer for _____

RNA; DNA

Bacterial cultures in ____ media can be quantified by Optical Density measurements at 600nm.

Liquid

Human pahtogens are

mesophilic

You are growing a culture of Streptococcus pneumoniae in Nutrient broth. You begin by inoculating the nutrient broth with 250 bacteria. You allow the bacteria to grow for 3 hours. The generation time for S. pneumoniae in nutrient broth is 60 minutes. How many bacteria will you have in this culture at the end of the experiment?

n0= 250

t=180

g=n/t

n=t/g

=180/60=3

Nt=No x 2^n

Nt= 250 x 2^3

Nt= 2000

All of the following are true about microbes and temperature, except

A. Microbes have mechanisms to control their temperature

B. Changes in temperature affect membrane fluidity

C. Changes in temperature affect enzymatic function

D. All of these are important

A. Microbes have mechanisms to control their temperature

When making serial dilutions of a culture to determine the CFUs, it is important to

generate 10-fold dilutions of the culture

E coli has wide growth ranges for pH, temperature, and oxygen. It will grow in both the presence or absence of molecular oxygen. Which category best describes E coli?

Facultative anaerobe

Why is PCR a useful molecular technique to quantify bacterial organisms?

it can detect one copy of a gene from a single cell

You are growing a laboratory strain of E coli in MacConkey Broth. You've inoculated the culture broth with 50 bacteria. After 4 hours of growth, you use a plate Colony Unit Assay and determine the culture now has 15000 bacteria, what is the approximate generation time?

Nt= 15000

N0= 50

t= 240 min

n=log(Nt/N0)/0.301

n= log (15000/50)/0.301

n= 8.23

g=t/n

g= 240/8.23

g= 30

Aerobic respiration culminates at a membrane embedded electron transport chain that generates a proton across the membrane. This process utilizes _____ to generate ATP from ADP and phosphate.

oxidative phosphorylation

how would you categorize the following nucleotide strand 5'- AGCTGCAA-3'?

DNA only

Which of the following is true about Sanitization:

Sanitization reduces the number of pathogenic microbes or discourages their growth

UV irridation kills bacteria by:

damaging chromosomal DNA

An antiseptic is distinguished from other chemical disinfectants by:

being able to be used on living tissues without harm

You are studying Thiobacillus thioxidans, a chemolithotroph. This bacterium:

generates ATP using oxidation of inorganic compounds

DNA replication is ______ meaning ________

semi conservative; each new piece of double stranded DNA is composed of a template strand and a newly synthesized strand of DNA

the process of pasteurization flash heats liquids in a controlled environment, The purpose of pasteurization is to ______

sanitize the liquid

During DNA replication of Okasaki fragments, RNA primers are removed, ______ synthesizes DNA to fill the gaps and _______ connects the DNA fragments.

DNA polymerase I; DNA ligase

______ is the tendency of a biological system to maintain internal stability, owing to the coordinated response to a situation or stimulus that would disturb its normal condition of function

homeostasis

You have isolated a new strain of Natronomonas pharaonis from the water of Lake Basaka in Ethiopia. The water of Lake Basaka has a pH of 9.6, thus, N.p. is best described as a:

Alkaliphile

A bacterium that uses glucose as an energy source has been isolated from an anaerobic environment. After incubation of the bacterium in liquid culture and using a cnadle jar to create an oxygen free environment, you conduct chemical analysis of the growth media. You find the production of Sulfates and H2S. Which of the following metabolic processes is the bacteria utilizing?

Anaerobic repiration

bacteria can rarely colonize and contaminate food with high sugar content, such as syrup, honey, or bags of sugar, even if these products are left open in warm temperatures. The reason they do not become contaminated is because bacteria that encounter these foods:

have a high sugar content which disrupts bacterial osmolarity

Autoclaving is a _____ procedure that utilizes _____ to kill microorganisms.

high level disinfectant, heat of 121 C and pressure of 15 psi

Phototrophic microbes can remove electrons from a source and transform photons of light to excite those electrons. What is/are the resulting molecules from Oxygenic Photosynthesis?

NADPH and ATP

Fermentation converts pyruvate to:

NAD+ and a waste product

Supercoiling is important for the DNA structure of the chromosome, because

it condenses the DNA so that it can fit inside the cell

The carbon fixing reactions of the Calvin Cycle require which of the following molecules?

CO2

Which statement about plasmids is incorrect?

Plasmids replicate independently of the chromosome

Plasmids carry genes that are essential for prokaryotic survival

Plasmids carry fewer genes than the chromosome

Plasmids are composed of circular DNA

Plasmids carry genes that are essential for prokaryotic survival

During anabolism, intermediates from _____ can be used to generate amino acids

the citric acid cycle and glycolysis

enveloped viral membranes are generally _____ studded with virus specific ______

lipid bilayers; proteins

If an operon can be regulated, one might say that GalR inhibits expression of galE. What does this mean?

galE refers to a gene

In a two component signal transduction pathway. the sensor kinase must first

bind to the external signaling molecule

identify the correct order of steps in the viral life cycle

Adsorption, Uncoating, Replication, Assembly, Release