1

Question 1

bacteria vs archaea

Answer 1

• bac: cell walls made of the polysaccharide peptidoglycan; some dont have cell walls
• arch: cell walls r other chemicals; none known to cause disease

Question 2

molds

Answer 2

• microscopic
• multicellular organisms that grow as long filaments
  that intertwine to make up the body of the mold. Molds reproduce
  by sexual and asexual spores, which are cells that produce
  a new individual without fusing with another cell. The cottony growths on cheese, bread, and jams are molds.

Question 3

yeasts

Answer 3

Yeasts are unicellular and typically oval to round. They reproduce
asexually by budding, a process in which a daughter cell grows off the mother cell. Some yeasts also produce sexual
spores. An example of a useful yeast is Saccharomyces cerevisiae, which causes bread to
rise and produces alcohol from sugar

Question 4

protozoa

Answer 4

Protozoa are single-celled eukaryotes that are similar to animals
in their nutritional needs and cellular structure. Most protozoa
are capable of locomotion, and one way scientists categorize
protozoa is according to their locomotive structures: pseudopods,
cilia,
or flagella.
- Some protozoa, such as the malariacausing
Plasmodium, are nonmotile in their
mature forms.
- Protozoa typically live freely in water, but some live inside
animal hosts, where they can cause disease. Most protozoa reproduce
asexually, though some are sexual as well.

Question 5

pseudopods

Answer 5

extensions of a cell that

flow in the direction of travel

Question 6

cilia

Answer 6

numerous,
short protrusions of a cell that beat rhythmically to propel the
protozoan through its environment

Question 7

flagella

Answer 7

also extensions of a cell but are fewer, longer, and more whiplike
than cilia

Question 8

algae

Answer 8

unicellular or multicellular photosynthetic eukaryotes;
that is, like plants, they make their own food from carbon
dioxide and water using energy from sunlight. They differ from
plants in the relative simplicity of their reproductive structures.
Algae are categorized on the basis of their pigmentation and the
composition of their cell walls.

Question 9

large algae

Answer 9

Large algae, commonly called seaweeds and kelps, are common
in the world’s oceans. Chemicals from their gelatinous cell
walls are used as thickeners and emulsifiers in many food and
cosmetic products as well as in a hardening agent called agar in
microbiological laboratory media.

Question 10

unicellular algae

Answer 10

common in freshwater
ponds, streams, and lakes and in the oceans as well. They are
the major food of small aquatic and marine animals and provide
most of the world’s oxygen as a by-product of photosynthesis.
The glasslike cell walls of diatoms provide grit for many
polishing compounds.

Question 11

parasitic worms

Answer 11

range in size
from microscopic forms to adult tapeworms over
7 meters (approximately 23 feet) in length. Even though most of
these worms are not microscopic as adults, many of them cause
diseases that were studied by early microbiologists. Further,
laboratory technicians diagnose infections of parasitic worms
by finding microscopic eggs and immature stages in blood,
fecal, urine, and lymph specimens.

Question 12

redi

Answer 12

When the flask remained unsealed,
maggots covered the meat within a few days. When the flask
was sealed, flies were kept away, and no maggots appeared on the
meat. When the flask opening was covered with gauze, flies were kept
away, and no maggots appeared on the meat, although a few maggots
appeared on top of the gauze.
- began to doubt aristotle’s theory of spontaneous generation

Question 13

needham

Answer 13

He boiled beef gravy and infusions of plant material
in vials, which he then tightly sealed with corks. Some
days later, Needham observed that the vials were cloudy, and
examination revealed an abundance of “microscopical animals
of most dimensions.” As he explained it, there must be a “life
force” that causes inanimate matter to spontaneously come to
life because he had heated the vials sufficiently to kill everything.

Question 14

spallanzani

Answer 14

Spallanzani boiled infusions for almost an
hour and sealed the vials by melting their slender necks closed.
His infusions remained clear unless he broke the seal and exposed
the infusion to air, after which they became cloudy with
microorganisms. He concluded three things:
• Needham either had failed to heat his vials sufficiently
to kill all microbes or had not sealed them tightly
enough.
• Microorganisms exist in air, can contaminate
experiments.
• Spontaneous generation doesnt occur

Question 15

pasteur’s experiments

Answer 15

• swan necked flasks
• Pasteur followed this experiment with demonstrations
  that microbes in the air were the “parents” of Needham’s microorganisms.
  He broke the necks off some flasks, exposing the
  liquid in them directly to the air, and he carefully tilted others
  so that the liquid touched the dust that had accumulated in
  their necks. The next day, all of these flasks were cloudy with
  microbes. He concluded that the microbes in the liquid were
  the progeny of microbes that had been on the dust particles in
  the air.

Question 16

pasteur fermentation conclusions

Answer 16

• yeast cells arise only frm other yeast cells
• yeasts r facultative anaerobes
• (anaerobic) bacteria ferment grape juice to produce acids; yeast cells ferment to produce alcohol

Question 17

pasteur 4 hypothesis

Answer 17

1. spontaneous fermentation occurs (rj)
2. air ferments grape juice (swan flask; rj)
3. bacteria ferment grape juice into alcohol (juice inoculated w/ bacteria n sealed; rj, acids)
4. yeasts ferment gj into alcohol

Question 18

germ theory of disease

Answer 18

Pasteur’s discovery that bacteria are responsible for spoiling
wine led naturally to his hypothesis in 1857 that microorganisms
are also responsible for diseases. This idea came to be known as
the germ theory of disease. Because a particular disease is typically
accompanied by the same symptoms in all affected individuals,
early investigators suspected that diseases such as cholera,
tuberculosis, and anthrax are each caused by a specific germ,
called a pathogen.14 Today we know that some diseases are genetic
and that allergic reactions and environmental toxins cause
others, so the germ theory applies only to infectious diseases.

Question 19

buchner

Answer 19

Studies on fermentation began with the idea that fermentation
reactions were strictly chemical and did not involve living organisms.
This idea was supplanted by Pasteur’s work showing
that fermentation proceeded only when living cells were present
and that different types of microorganisms growing under
varied conditions produced different end products.
In 1897, the German scientist Eduard Buchner (1860–1917)
resurrected the chemical explanation by showing that fermentation
does not require living cells. Buchner’s experiments demonstrated
the presence of enzymes, which are cell-produced
proteins that promote chemical reactions. Buchner’s work
began the field of biochemistry and the study of metabolism.

Question 20

etiology

Answer 20

study of causation of disease

Question 21

anthrax

Answer 21

potentially fatal disease, primarily of animals, in which toxins
produce ulceration of the skin. Anthrax, which can spread to
humans, caused untold financial losses to farmers and ranchers
in the 1800s.

Question 22

koch and anthrax

Answer 22

Koch carefully examined the blood of infected animals,
and in every case he identified a rod-shaped bacterium that
formed chains. He observed the formation of resting stages (endospores)
within the bacterial cells and showed that the endospores
always produced anthrax when they were injected into
mice. This was the first time that a bacterium was proven to
cause a disease. He had been fortunate when he chose anthrax
for his initial investigations, because anthrax bacteria are quite
large and easily identified with the microscopes of that time.

Question 23

how did koch solve his problem

Answer 23

However, most bacteria are very small, and different types exhibit
few or no visible differences. Koch puzzled how he was to
distinguish among these bacteria.
He solved the problem by taking specimens (e.g., blood,
pus, or sputum) from disease victims and then smearing the
specimens onto a solid surface such as a slice of potato or a
gelatin medium. He then waited for bacteria and fungi present
in the specimen to multiply and form distinct colonies. Koch hypothesized that each colony consisted
of the progeny of a single cell. He then inoculated samples
from each colony into laboratory animals to see which caused
disease.

Question 24

koch’s postulates

Answer 24

series
of steps that must be taken to prove the cause of any infectious
disease.
1. The suspected causative agent must be found in every case
of the disease and be absent from healthy hosts.
2. The agent must be isolated and grown outside the host.
3. When the agent is introduced to a healthy, susceptible host,
the host must get the disease.
4. The same agent must be found in the diseased experimental
host.

Question 25

gram stain

Answer 25

involves the application of a series of dyes, leaves
some microbes purple and others pink. We now label the first
group of cells as Gram positive and the second as Gram negative

Question 26

nosocomial infections

Answer 26

infections acquired in a

health care setting

Question 27

lister

Answer 27

modified and advanced the
idea of antisepsis in health care settings. As a surgeon, Lister
was aware of the dreadful consequences that resulted from the
infection of wounds. Therefore, he began spraying wounds,
surgical incisions, and dressings with carbolic acid (phenol),
a chemical that had previously proven effective in reducing
odor and decay in sewage.

Question 28

snow

Answer 28

Snow had been studying
the propagation of cholera and suspected that the disease was
spread by a contaminating agent in water. In 1854, he mapped
the occurrence of cholera cases during an epidemic in London
and showed that they centered around a public water supply
on Broad Street.
Though Snow did not know the cause of cholera, his careful
documentation of the epidemic highlighted the critical need
for adequate sewage treatment and a pure water supply

Question 29

immunology

Answer 29

Jenner began the field of immunology—

the study of the body’s specific defenses against pathogens. (also kitasato n von behring)

Question 30

jenner

Answer 30

tested the hypothesis that a mild disease called cowpox provided
protection against potentially fatal smallpox. After
he intentionally inoculated a boy with pus collected from a
milkmaid’s cowpox lesion, the boy developed cowpox and
survived. When Jenner then infected the boy with smallpox
pus, he found that the boy had become immune to smallpox. In 1798, Jenner
reported similar results from additional experiments, demonstrating
the validity of the procedure he named vaccination
after Vaccinia virus,24 the virus that causes cowpox

Question 31

immunization

Answer 31

Because
vaccination stimulates a long-lasting response by the body’s
protective immune system, the term immunization is often used
synonymously today.

Question 32

vaccine

Answer 32

Pasteur later capitalized on Jenner’s work by producing
weakened strains of various pathogens for use in preventing
the serious diseases they cause. In honor of Jenner’s work
with cowpox, Pasteur used the term vaccine to refer to all
weakened, protective strains of pathogens. He subsequently
developed successful vaccines against fowl cholera, anthrax,
and rabies.

Question 33

ehrlich

Answer 33

chemotherapy. Gram’s discovery that stained bacteria could be differentiated
into two types suggested to the German microbiologist Paul
Ehrlich (1854–1915) that chemicals could be used to kill microorganisms
differentially. To investigate this idea, Ehrlich undertook
an exhaustive survey of chemicals to find a “magic bullet”
that would destroy pathogens while remaining nontoxic to humans.
By 1908, he had discovered a chemical active against the
causative agent of syphilis, though the arsenic-based drug was
toxic to humans.

Question 34

golden age of micro

Answer 34

a time
when researchers proved that living things come from other
living things, that microorganisms can cause fermentation and
disease, and that certain procedures and chemicals can limit,
prevent, and cure infectious diseases.

Question 35

Avery-MacLeod-McCarty

Answer 35

Avery wanted to find the transforming substance (transformation: a change in genotype and
phenotype due to the assimilation of external DNA by a cell)
- Avery focused on three main candidates: DNA, RNA, and protein. Avery broke open the heat-killed pathogenic bacteria and extracted the cellular contents. He treated each of three samples with an agent that inactivated one type of molecule, then tested the sample for its ability to transform live nonpathogenic bacteria. Only when DNA was allowed to remain active did transformation occur.

Question 36

beadle n tatum

Answer 36

working with the bread mold Neurospora crassa, established that a gene’s activity is related to the func ˘ -
tion of the specific protein coded by that gene.

Question 37

pauling

Answer 37

proposed that gene sequences could provide a
means of understanding evolutionary relationships and processes,
establishing taxonomic categories that more closely
reflect these relationships, and identifying the existence of microbes
that have never been cultured in a laboratory.

Question 38

woese

Answer 38

discovered that significant
differences in nucleic acid sequences among organisms
clearly reveal that cells belong to one of three major
groups—bacteria, archaea, or eukaryotes—and not merely
two groups (prokaryotes and eukaryotes), as previously
thought.

Question 39

cat scratch disease

Answer 39

Scientists showed in 1990 that cat scratch disease is caused
by a bacterium that had not been cultured. The bacterium
was discovered by recognizing the sequence of a portion of
its ribonucleic acid that differs from all other known ribonucleic
acid sequences.

Question 40

gene therapy

Answer 40

An exciting new area of study is the use of recombinant DNA
technology for gene therapy, a process that involves inserting
a missing gene or repairing a defective one in human cells. In
such procedures, researchers insert a desired gene into host
cells, where it is incorporated into a chromosome and begins to
function normally.

Question 41

winogradsky

Answer 41

elucidated the role of microorganisms in the recycling of sulfur.

Question 42

beijerinck

Answer 42

discovered
bacteria capable of converting nitrogen gas (N2) from the
air into nitrate (NO3), the form of nitrogen used by plants

Question 43

The work of Jenner and Pasteur on vaccines showed that

Answer 43

the body can protect itself from repeated diseases by the

same organism.

Question 44

von behring, kitasato

Answer 44

working in Koch’s laboratory, reported
the existence in the blood of chemicals and cells that fight
infection. Their studies developed into the fields of serology n immunology

Question 45

serology

Answer 45

the study of blood serum—specifically, the chemicals in the

liquid portion of blood that fight disease

Question 46

mad cow disease

Answer 46

“mad cow disease” because most
humans with the condition acquired the pathogen from eating
infected beef). Because vCJD affects the brain by slowly
eroding nervous tissue and leaving the brain full of sponge-like
holes, the signs and symptoms of vCJD are neurological.
Ellen’s disease started with insomnia, depression,
and confusion, but eventually it
led to uncontrollable emotional and verbal
outbursts, inability to coordinate movements,
coma, and death. Typically the disease lasts
about a year, and there is no treatment.
Variant Creutzfeldt-Jakob disease is an
emerging disease, that is, a disease arising
in the past two decades either because it is new to a
population or because it is newly recognized.

Question 47

nightingale

Answer 47

One of her first requisitions in
the military hospital was for 200 scrubbing brushes, which she
and her assistants used diligently in the squalid wards. She
next arranged for each patient’s filthy clothes and dressings to
be replaced or cleaned at a different location, thus removing
many sources of infection. She thoroughly documented statistical
comparisons to show that poor food and unsanitary conditions
in the hospitals were responsible for the deaths of many
soldiers