question

anoxygenic photosynthesis

answer

occurs under anaerobic conditions
oxygen is not an end product
Hydrogen sulfide serves as a source of ruducing power and is converted by these organisms (i.e. Chromatium) to elemental sulfur, which is stored inside of the cells as elemental sulfur

question

Name a phototrophic purple sulfer bacteria species.

answer

Chromatium

question

What is meant by chemoautotrophy in bacterial species?

answer

bacteria that fix carbon dioxide for their carbon needs and obtain energy for cell growth by oxidizing inorganic ions.

question

Name a sulfate-reducing bacteria.

answer

Desulfovibrio desulfuricans

question

What is sulfate respiration?

answer

Cellular respiration whereby sulfate is reduced to H₂S by sulfate-reducing bacteria such as Desulfovibrio desulfuicans.
A pocess in which sulfate serves as a terminal electon acceptor and its reduction is interfaced with electron transport to produce ATP
for some organisms the H₂S reacts with various metals in the mud and forms a black precipitate

question

What is bacteriochlorophyll and carotenoids?

answer

Pigments produced by bacteria that, in the case of phototrophic purple sulfur bacteria, impart colors as purple, red, or brown in areas where this bacteria is growing.

question

What are the characteristics of phototropic green sulfur bacteria?

answer

anoxygenic photosynthesis
converts H₂S to elemental sulfur
stores the sulfur outside the cells
Aquires carbon by fixing carbon dioxide into intermediates in the Krebs cycle
grow green in the anaerobic areas due to the presence of the pigment, bacteriochlorophyll

question

Name a species of phototrophic green sulfur bacteria.

answer

Chlorobium

question

Name two species of purple nonsulfur bacteria.

answer

Rhodospirillum
Rhodobacter

question

What are the characteristics of purple nonsulfur bacteria?

answer

normally grow photoheterotrophically using various organic compounds as a carbon source (i.e. succinate, glutamate)
obtain energy from anoxygenic photosythesis
can grow photoautotorphically using carbon dioxide for a carbon source and hydrogen gas or low concetrations of sulfide as reducing power
can completely switch metabolic gears and grow by heterotrophic eans on organic acids using respiration if light becomes very limited
found in microaerphilic areas
are brown to reddish in color

question

Name three chemolithotrophic bacteria species and their characteristics.

answer

Thiobacillus: aerobic; gram-negative, rod-shaped cells; some species are motile; all species fix carbon dioxide by the Calvin-Benson cycle
Beggiatoa: aerobic; colorless cells; occur in filaments with constant width; cells may contain sulfur granules when grown in the presence of H₂S
Thiobacillus: fixes carbon dioxide for its carbon requirements and obtains energy by oxidizing reduced forms of sulfur to produce sulfate or sulfuric acid

question

In the Winogradsy column, for what do the cyanobacteria and algae provide, and where would the be found?

answer

they grow on the surface water of the column where they produce oxygen which keeps the upper portion of the column aerobic

question

What are cellulose digesters?

answer

organisms which degrade and ferment the products of cellulose
Cellulomonas degrades cellulose
Clostridium and other bacteria then ferment the monaccharides derived from the cellulose to podroduce organic acids such as lactate and acetate

question

What advantages does the streak-plate method have over the pour-plate method?

answer

streak-plate requires fewer materials
gives as good isolation as needed, when properly done

question

What advantages does the pour-plate have over the streak-plate method?

answer

produces a good isolation
requires less skill

question

Why is the loop flamed before it is placed in the culture and why is it flamed after completing inoculation?

answer

loop is flamed before it is used to gather a culture in order to prevent contamination from any organisms that may be on the loop
loop is flamed after completing inoculation in order to kill any organisms on the loop to prevent contamination for future use

question

Before inoculating and pouring molten nutrient agar into a place, why must the agar first be cooled to 50°C?

answer

to prevent condensation which could cause moisture on the agar surface allowing for the organisms to spread over the surface resulting in a faulty isolation process

question

Why should plates be inverted during incubation?

answer

in order to reduce possible condensation on the surface of the agar
condensation could cause the organisms to spread and conjoin making it difficult to study colonies

question

In what ways do the macroscopic features of bacterial colonies differ from that of molds?

answer

molds branch outwards in non-circular groups that have a fuzzy appearance
bacteria grow in circular patterns and do not branch out

question

Why is the level of contamination measured as number of colonies rather thatn size of colonies?

answer

different colonies tell how many bacteria are in an area
size of colonies tells the rate of bacterial growth

question

Should one be concerned to find bacteria or molds on the skin?

answer

bacteria and on the skin is of no concern as they are a natural occurance
many are non-pathogenic and protect against pathogens
abnormal amounts could be cause for concern

question

How can microbial levels be controlled on the skin?

answer

hand washing

question

How can microbial levels be controlled on surfaces in the environment?

answer

antibacterial cleansers
bleach

question

How can microbial levels be controlled in the air?

answer

air purifiers

question

Compare bacteria to eukaryotic cells.

answer

bacteria much smaller 0.2-2.0 µm (euk. 10-100µm)
bacteria have a circular free-floating DNA ring (euk. compressed DNA in a membrane bound nucleus that forms chromosomes)
Bacteria have free floating ribosome subunits 30S and 50S which make a 70S compound (euk. ribosomes are mostly on the RER, are composed of subunit 40S and 60S making a 80S compound
bacteria have respiration and photosynthesis occurring within a cell wall. (euk. takes place within the cell in specialized compartments)
bacteria have flagella that facilitate movement by rotating around the base, and have two different types of motility: runs and tumbles. In eukaryotic cells, there are both flagella and cilia, and the flagella facilitate movement by a wave motion.

question

Define the term colony with regards to bacterial growth on a solid media.

answer

a grouping of individuals of the same species rising from a single bacteria cell. Colonies are genetically identical as they are formed from a single cell that replicates and grows outward

question

What colony characteristics can be used for differentiation of bacterial species? Compare Serratia marcescens and Micrococcus luteus

answer

differentiation by color, shape, gram-stain, and grouping as observed under the microscope.
M. luteus: gram-positive (purple), form tetrads
S. Marcescens: gram-negative, do not group in any clusters.

question

Why is dilution a necessary part of pure culture preparation?

answer

When diluted, the individual cells are spread far apart from one another and have the space and resources to expand outward.

question

Define the term 'pure colony'.

answer

An isolated group of bacteria cell of all the same species.

question

What does 'oxygenic photosynthesis' mean?

answer

That oxygen is an end product of photosynthesis.

question

Do gram-positive bacteria have an outer membrane?

answer

No, gram-positive bacteria have a thick layer peptidoglycan that comprises the cell wall. It is this layer that retains the purple color of the crystal violet that was used in the gram-staining procedure.

question

Do gram-negative bacteria have a thick peptidoglycan layer?

answer

No, gram-negative bacteria have a thin layer of peptidoglycan that is covered by a thin membrane. The crystal violet runs out of the cell during the decolorization stage of the gram-staining procedure and takes on the pink color of the counter stain, safranin.

question

Why do you have to sterilize the loop in between streaks when you perform a quadrant streak?

answer

The first sterilization is to remove any microbes that can contaminate the culture. Sterilization between each streak is to kill the microbe on the loop so that isolated cultures can be streaked from the already streaked area

question

Name the groups of bacteria that you want to enrich with the Winogradsky column. (7)

answer

Beggiatoa
Thiobacillus
Rhodospirillum
Chromatium
Chlorobium
Clostridium
Desulfovibrio

question

What is the purpose of the Winogradsky column?

answer

to study a variety of diverse bacteria such as the sulfate reducers, photosynthetic bacteria, and chemolithotrophs

question

What does 'anoxygenic photosynthesis' mean?

answer

That oxygen is not an end product of photosynthesis.

question

For most bacteria, the cell is surrounded by a cell wall composed of a unique molecule called........?

answer

peptidoglycan

question

Which objective on the light microscope is being used with 'immersion oil'?

answer

The 100x high power immersion

question

do Rotifers belong to the prokaryotes?

answer

No.

question

What can you do to increase the contrast when you use the microscope?

answer

close the diaphragm in the condensor.

question

What are pseudohyphae, and what organism produces them?

answer

Pseudohyphae ae filaments that are budding fungi that stretch out to appear similar to hyphae. They are produced by yeasts.

question

Are diatoms eukaryotes?

answer

yes

question

Which objective on teh light microscope is considered teh 'high dry'?

answer

40x

question

In which processes are microorganisms involved?

answer

infection
decomposition of organic material
O2 production
food production

question

Who developed the formal system for classifying and naming organisms?

answer

Carolus Linnaeus

question

What is Biogenesis?

answer

The theory that development of life forms from pre-existing life forms.

question

What would be essential to the experiment when setting up an experiment to disprove spontaneaous generation in a liquid medium?

answer

using a sterile liquid and eliminating exposure to microorganisms

question

What were the components regarding Louis Pasteur's experiments with the S-neck flask?

answer

air exchange was involved
a food source was provided
the possibility of contamination was removed
all; pre-existing microorganisms wer killed

question

Who proved that a microbe could cause disease?

answer

Koch

question

Of what is mycology a study?

answer

molds, yeast, and mushrooms

question

In which situation would Koch's postulates be utilized?

answer

In the determination of the cause of a patient's illness in a hospital microbiology lab

question

What was essential for Edward Jenner's vaccination process?

answer

The idea that exposure to a milder disease form may produce immunity

question

What structure does light pass through after leaving the condenser in a compound light microscope?

answer

specimen

question

What is the purpose of a mordant in the Gram stain?

answer

to prevent the crystal violet from leaving the cells

question

A microorganism measures 5 µm. What is its length in mm?

answer

0.005 mm

question

You are performing a Gram stain on gram-negative bacteria and you stop after the addition of teh mordant. What is the appearance of teh bacteria at theis point?

answer

purple

question

You are performing a Gram stain on gram-negative bacteria and you stop after the decolorizer step. What is the appearance of the bacteria at this point?

answer

colorless

question

Asume you stain Bacillus by applying malachite green with heat and the counterstaining with safranin. Though the microscope, the green structures are.....

answer

endospores

question

Which of the following statements is incorrect regarding prokaryotic cells?

a) their DNA is not enclosed within a
membrane
b) they lack membrane-enclosed organelles
c) they typically have a circular chromosome
d) they reproduce by binary fission
e) they lack a plasma membrane

answer

e) they lack a plasma membrane

question

What happens to a bacterial cell when it is placed into a solutioncontaining 5% NaCl?

answer

water will move out of the cell

question

Which of the following pairs are mismatched?

a) ER - internal transport
b) Golgi - secretion
c) mitochondria - ATP
d) centrosome - food storage
e) lysosome - digestive enzymes

answer

d) centrosome - food storage

question

Which organelle most closely resembles a prokaryotic cell?

answer

mitochondria

question

for what are the terms "run" and "tumble" generally associated?

answer

taxic movements of the cell

question

Does anaerobic respiration involve the reduction of an organic final electron acceptor?

answer

no

question

How would a noncompetitive inhibitor interfere with a reaction involving enzymes

answer

It would attach to the cell at a place other that the active site. This attachment will cause the shape of the active site to change thus inhibiting the enzyme to react with its specific substrate.

question

What is fermentation?

answer

The partial oxidation of glucose with organic molecules serving as electron acceptors

question

What do you call an organism which uses CO2 for its carbon source and H2 for its energy source?

answer

chemoautotroph

question

Cyanobacteria are a type of

a) chemoautotroph
b) chemoheterotroph
c) photoautotroph
d) photoheterotroph

answer

c) photoautotroph

question

A sample of milk is tested for its bacterial content in a plate count assay. A one-milliliter sample of the milk is diluted in a 1:10 dilution series. One milliliter of teh third dilution tube is plated in a pour plate. After incubation, the plate has 54 colonies. How many cells did the original milk sample contain?

answer

54,000 cells

question

How do most bacteria reproduce?

answer

binary fission

question

In which pH do most human associated bacteria grow best?

answer

pH 7

question

Three cells with generation times of 60 minutes are inoculated into a culture medium. How many cells are there afer 5 hours?

answer

96

question

Which structures of a mold colony are important to identify its genus?

answer

sporangia
hyphae septated
hyphae non-septated

question

Whe you perform a quadrant streak, but the bacterial colonies are not separated in the 4th quadrant, what mistake have you most likely made?

answer

You forgot to sterilize the loop in between streaks

question

Whould the Gram stain show Gram negative and Gram positive cells correctly if you would start with safranin and counterstain with crystal violet? Which color would teh Gram-negarive and Gram-positive cells have at the end of teh staining procedure?

answer

No. All cells would be purple

question

Why is the decolorization step important in Gram staining?

answer

It washes the crystal violet out of the Gram-negative organism so that the counterstain can be seen

question

Do gram-negative bacteria have a thick peptidoglycan layer?

answer

NO

question

For what are microorganisms responsible?

answer

infection
decomposition of organic material
oxygen production
food production

question

Who developed the formal system for the classification and naming of organisms?

answer

Carolus Linnaeus

question

To what does biogenesis refer?

answer

to the development of life forms from preexisting life forms

question

If you were setting up an experiment to disprove spontaneous generation in a liquid medium, what would be essential to the experiment?

answer

using a sterile liquid and eliminating exposure to microorganisms.

question

In Louis Pasteur's experiments with the S-flasks, what were the conditions?

answer

air exchange was involved
a food source was provided
the possibility of contamination was removed
all pre-existing microorganisms were killed

question

Who proved that a microbe could cause disease?

answer

Koch

question

Of what is mycology the study?

answer

molds,yeast, and mushrooms

question

What are Koch's postulates?

answer

the microorganism must be found in all organisms suffering from the disease, but not in healthy organisms
the microorganism must be isolated from a diseased organism and grown in pure culture
the cultured microorganism should cause disease when introduced into a healthy organism
the microorganism must be re-isolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent

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