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Bacteria & Enzyme Inhibitor - Microbiology
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Bacteria & Enzyme Inhibitor – Microbiology

This capter covers bacteria and enzyme inhibitor of microbiology.

What is microbiology?

Microbiology is the study of:

living things that are too small to see without a microscope  – correct




What kind of organism would a microbiologist NOT study?

none of these  – correct




What is the standard metric unit for 10-3m ?

millimeter (mm)  – correct

micrometer (um)

nanometer (nm)

centimeter (cm)

About what size are most bacteria?

1 um (micrometer)  – correct

0.5 nanometer (nm)

1.5 millimeter (mm)

2 Angstrom

To whom do we attribute the invention of the microscope?

Anton van Leeuwenhoek  – correct

Louis Pasteur

John Snow

Fransesco Redi

The theory of spontaneous generations holds that

life can arise from non-living material – correct

life can only arise from living things

viruses are not alive

bacteria are not alive

What is objective of Koch’s postulates?

Identify the specific bacterium that causes a specific disease  – correct

isolate bacteria

refute spontaneous generation

aseptic surgery

Which of these are contributions of Louis Pasteur to the field of microbiology?

all of these  – correct

rabies vaccine

refutation of spontaneous generation

invention of the autoclave

What was John Snow’s major contribution to microbiology?

he was the first epidemiologist – correct

Snow invented the microscope

he invented Pasteurization

invented the autoclave

What concept did Ignaz Semmelweis contribute to health care?

sanitation; washing hands  – correct

he discovered penicillin

father of epidemiology

he founded the red cross

Which of these structures is NOT present in both prokaryotes and eukaryotes?


plasma membrane

nucleus  – correct

nucleic acids

What is taxonomy?

evolutionary descent

the science of classification  – correct

the study of taxes

making stuffed animals

What is phylogeny?

evolutionary descent  – correct

the study of phyla

binomial nomenclature


What is a heterotroph?

a unicellular organism

a eukaryote

a sexually reproducing organism

an organism that requires organic carbon for energy and as a source of carbon  – correct

What species is Pseudomonas aeriginosa?




aeriginosa  – correct

Why are bacteria hard to classify?

all of these   – correct

most cannot be cultured in the laboratory

they lack morphological diversity

there is a high degree of lateral gene transfer among bacteria

How can DNA be used to classify bacteria?


DNA sequencing

determine G+C ratio

all of these   – correct

Classifying a bacterium is different than identifying a bacterium.



What range of number of colonies on a standard Petri plate is considered countable?

30 to 300   – correct

20 to 200

1 to 500

up to 1000

If I took 1 ml of a culture containing 7,000 cells per ml and added it to a tube containing 9 ml of sterile water, the concentration of cells in the second tube would be about

700 cells per ml   – correct

7,000 cells

7,000 cells per ml

70 cells per ml

If I took 2 ml of a culture containing 4000 cells/ml and added that to a tube containing 2 ml of sterile water, the concentration of cells in the second tube would be

4000 cells/ml  – correct

8000 cells

2000 cells/ml

none of these

should be 2000 cells/ml

I collect a volume of 0.1 ml of a culture. What volume of sterile water should I add to achieve a 1:10 dilution?

0.9 ml   – correct

1 ml

0.1 ml

10 ml

I have a culture estimated to contain 106 colony forming units (CFU)/ml. How many 1:10 dilutions do I need to reduce the concentration to about 102 CFU/ml?

4   – correct




If I plate 0.1 ml of a culture is counts as a 1:10 dilution.

True   – correct


What do we call the set of lenses nearest our eyes?

Oculars   – correct



iris diaphragm

If I am looking through a 10X ocular and 10X objective, what is the total magnification?

100X   – correct




What is contrast?

differences in light intensity   – correct

increase in apparent size


depth of field

What is resolution?

ability to distinguish two closely spaced points   – correct

increase in apparent size

differences in light intensity


Which of these types of microscope can increase the contrast of a specimen without staining it?

all of these  – correct

dark field

phase contrast


Which of these types of microscopes will give me the best resolution of a thick specimen?

con focal  – correct

phase contrast


transmission electron

The limit of useful magnification of a microscope using white light to iluminate the specimen is about

1000X  – correct



there is no limt

Which of these is an advantage of epifluorescence microscopy?

multiple staining   – correct

resolution of thick specimens

do not need to stain specimen

very inexpensive

The principle advantage of electron microscopes over light microscopes is

Much higher useful magnification   – correct

ease of sample preparation

better resolution of thick specimens

specimens do not have to be stained

What is the standard metric unit for 1 x 10-9m?

Nanometer  – correct




The hydrolysis of starch into glucose and maltose molecules is an example of;

dehydration synthesis

catabolism   – correct

cheap starch


What is an enzyme?

a catalyst  – correct

a substrate

a lipid

none of these

How do enzymes speed up reactions?

Enzymes increase the temperature of the solution

Enzymes add protons to the system

They lower the energy of activation   – correct

Enzymes add energy to the reaction

What is an enzyme’s substrate?

the produt of the reaction

the molecule upon which it acts   – correct

the amino acid composition of the enzyme

all of these

What is an enzyme’s active site

the area where it moves atoms up a concentration gradient

its substrate

none of these

the place on the enzyme where it interacts with its substrate   – correct

I am measuring the rate at which the product of an enzyme catalyzed reaction accumulates in a solution. When I add an inhibitor, the rate goes down, and adding more substrate does not change the rate. What kind of inhibitor is this?


non-competitive   – correct

temperature sensitive

protein denaturant

You are studying a biosynthetic pathway and you discover that the final product of the pathway is a non-competitive inhibitor of the first enzyme in the pathway. This phenomenon is called

product cycling

protein denaturation

all of these

feed back inhibition   – correct

What do we know about the enzymes produced by bacteria living in 95oC water?

they are stable and active at 95o   – correct

these will be denatured

these must be constructed of novel amino acids

nothing can live at 95o

What are the energy and carbon sources of a photoheterotroph?

light, inorganic carbon

light, organic carbon   – correct

organic carbon

reduced inorganic molecules, inorganic carbon

What is a psychrophile?

organism that lives in high salt environments

organism that lives at low pH

people that love horror movies

organism that lives at low temperatures  – correct

Quiz Score: 6 out of 10

Score for this quiz: 6 out of 10

Submitted Sep 27 at 10:19pm

This attempt took 11 minutes.

Which of these catabolic ‘styles’ is most  efficient at extracting energy from organic carbon compounds?

aerobic respiration   – correct

anaerobiosis and fermentation

anaerobic respiration

they are all the same

What is the objective of cellular respiration?

convert energy stored in carbon -carbon bonds into ATP   – correct

acquiring oxygen

making water


Two ATPs per glucose are generated in fermentation


False  – correct

Humans are obligate aerobes. Therefore our cells never do fermentation.


False  – correct

Which of these is a product of the transition reaction?

all of these  – correct




Some ATP’s are generated directly in the Krebs cycle.

True   – correct


In cellular respiration, when carbon-carbon bonds are broken, hydrogens are released and these are stored on co-enzymes like NAD.

True   – correct


what is chemiosmosis?

using energy to establis a proton gradient across a membrane   – correct

the osmosis of chemicals

the movement of water across a membrane

none of these

What is the role of oxygen in aerobic cellular respiration?

it is the terminal electron acceptor  – correct

it is to burn carbon

to make water

oxidize NAD

Some bacteria use a molecule other than oxygen at the terminal electron acceptor.

True  – correct


In what phase of the bacteria growth curve does the number of cells increase exponentially?

none of these

log phase  – correct

stationary phase

lag phase

What factor is likely to cause a broth culture to transition from log phase to stationary phase?

running out of physical room

running out of water

all of these

running out of a particular nutrient  – correct

What factor is likely to cause a broth culture to transition from stationary phase to death phase?

the accumulation of toxic wastes  – correct

to run out of room

running out of energy

to run out of a particular nutrient

What are complex media?

growth media that contain ingredients that are not fully characterized   – correct

media whose exact composition is know

media that repress the growth of certain types of bacteria

none of these

What are differential media?

differential media suppress the growth of some bacteria

contain ingredients to encourage the growth of certain types of bacteria

they allow us to distinguish types of bacteria based on an observable biochemical reaction  – correct

all of these

What is the objective of streaking for isolation?

determining the concentration of bacteria in a broth culture

identifying a bacterium

preventing contamination

obtaining pure cultures   – correct

What is the purpose of a chemostat?

maintain cultures in log phase  – correct

maintain cultures in stationary phase

prevent contamination

determine the concentration of cells in a broth culture

Which of these is a techniques for determining the concentration of cells in a broth cuture?

serial dilution and plating

all of these  – correct

most probable number

optical density

I counte 67 colonies on a plate made by spreading 100ul of a 10-7 dilution of  a culture. What was the original cell denisty of the culture?

6.7 x 107 CFU/ml

67 x 107 CFU/ml

6.7 x 109 CFU/ml  – correct

unable to determine from the information supplied

What does CFU stand for when expressing the concentration of bacteria in a broth culture?

colony forming units  – correct

none of these

cell forming units

citizens for unity

DNA replication is semi-conservative. That means that daughter molecules

both daughter molecules contain a mixture of old and new DNA in both strands

are iddferent in that one caontains the old strands and one contains the newly synthesized strands

contains one oreiginal and one newly synthesized strand  – correct

none of these

DNA polymerase will synthesize a new strand of DNA in one direction only; 5′ to 3′.

True  – correct


At each replication fork, one new strand gets synthesized faster than the other.

True  – correct


What is the function of DNA?

deliver amino acids to the ribosome

carry information from the nucleus to the ribosom

to carry information, usually recipes for the primary structure of proteins   – correct

none of these

How do DNA and RNA molecules differ?

number of strands; 1 or 2

base pairing


all of these   – correct

What is the function of the promoter region of a gene or operon?

the start of translation

the start of transcription

site where RNA polymerase can bind to the DNA   – correct

regulates rate of transcription

What is an intron?


the coding regions within a gene

a none coding region within a gene  – correct


What is the function of tRNA?

to deliver amino acids to the ribosome  – correct

transfer information from the nucleus to the ribosome

part of the ribosome structure

store the recipes for proteins

What kind of molecule carries anticodons?


tRNA  – correct



What is the function of RNA polymerase?

synthesize a strand of DNA following an RNA template

synthesize a molecule of RNA using DNA template  – correct

make a protein

replicate RNA molecules

What is an operon?

a cluster of gene with related function that are co-regulated  – correct

site of protein synthesis

non-coding regions in genes

site where RNA polymerase can bind to the DNA

Gene that are normally ‘on’ but can be turned ‘off’ are


none of these


repressible  – correct

How does the presence of lactose induce expression of the Lac operon?

allolactose binds to and inactivates Lac I, the inhibitor protein   – correct

lactose blocks transport of tryptophan

lactose binds to the Lac operator region

it binds to the Lac promoter region

If both glucose and lactose are present in the growth medium, transcription of the Lac operon will not be induced. This is called

cheap lactose


catabolite repression  – correct

catabolite induction

Why is it to the cell’s advantage for tryptophan to suppress transcription of the Trp operon?

so that it can utilize lactose

to stimulate the synthesis of other amino acids

so the cell won’t waste energy overproducing the amino acid  – correct

all of these

A gene suffers a single base substitution mutation, and the resulting protein has the same length but a different primary structure than the original protein. What kind of mutation was it?

frame shift


missense  – correct


What is a mutation?

an inversion

an alteration in the mRNA

an alteration of the primary structure of a protein

a random change in DNA base sequence  – correct

In prokaryotes, which are haploid, all phenotypic variation is due to mutation.


False   – correct

Genes that are always expressed are called

Constitutive  – correct




What do restriction endonucleases do?

repair DNA

copy DNA

cut DNA  – correct

prime DNA replication

What does agarose gel electrophoresis do?

separates DNA fragments by sequence

cuts DNA

transfers DNA to another bacterium

separates DNA fragments by size  – correct

Why do some cloning vectors (plasmids) contain antibiotic resistance genes?

to select for successful clones  – correct

prevent contamination

make the clones stronger

all of these

What is biotechnology?

genetically modified organisms

cutting DNA

genetic recombination

using living things to make a product  – correct

What is transduction?

horizontal DNA transfer via phage  – correct

taking up DNA from the environment

when bacteriophage infect a bacterium

horizontal DNA transfer via pili

What is vertical transfer of genetic information?

transfer of genetic information between cells of the same generation

transfer of DNA via pili

When offspring receive genetic information from their parents – correct

transfer of DNA via phage

What is conjugation?

slecting plasmids that contain the gene of interest

transfer of DNA via phage

abosorbing DNA from the environment

the horizontal transfer of DNA via a pillus  – correct

What is reverse transcriptase?

RNA polymerase

an enzyme that uses an RNA template to make DNA  – correct

DNA polymerase


What is polymerase chain reaction (PCR) used for?

PCR seal nicks in the DNA backbone

make a strand of DNA using an RNA template

PCR transfer DNA into eukaryotic cells

to make many copies of a specific portion of a DNA template  – correct