Unit 1 Review

Question 1

Which of the following statements is FALSE?
-Microbial cells can exist as single cells.
-Microbial cells carry out their life processes of
growth independently.
-Microbial cells include both bacteria and viruses.
-Microbial cells are surrounded by a cytoplasmic
membrane.

Answer 1

-microbial cells include both bacteria and viruses

Question 2

In what/which domain(s) of life is/are
microorganisms represented?

Answer 2

Archaea, Bacteria, and Eukarya

Question 3

The person who described the “wee
animalcules” was _______

Answer 3

Antoni van Leeuenhoek

Question 4

Louis Pasteur developed the
vaccine(s) for:

Answer 4

anthrax, fowl cholera, and rabies

Question 5

Transparent double-sided dishes used
for growing microbes are most
commonly called _________

Answer 5

Petri dishes.

Question 6

What are the
accomplishments of Louis Pasteur?

Answer 6

-Determined that the alcohol-making process was
mediated by microbial fermentation and thus
refuted the theory of spontaneous generation
-Developed heat sterilization techniques that
involved the creation of a specialized swannecked flask
-Developed the first rabies vaccine and treated
thousands of individuals

Question 7

What is a pure culture?

Answer 7

a population of identical cells

Question 8

Robert Koch contributed to the field of microbiology by:

Answer 8

develop the tuberculin test, formulate four postulates for
definitively linking a specific microorganism to a specific
disease, and use agar as a solidifying agent in growth
media.

Question 9

The structure that confers structural
strength on the cell is known as the __________

Answer 9

cell wall.

Question 10

Cyanobacteria and purple sulfur
bacteria both obtain energy from light.
However, only the ________ are capable
of releasing ________.

Answer 10

cyanobacteria / oxygen

Question 11

________ was the first to describe
microorganisms, while ________ was the first person
to see bacteria.

Answer 11

Robert Hooke / Antoni van Leeuwenhoek

Question 12

Archaea and Bacteria are unified as prokaryotes in lacking ________ which Eukarya contain, such as mitochondria.

Answer 12

nuclei and membrane-enclosed organelles

Question 13

Electron microscopy has greater
________ than light microscopy, because the wavelength of visible light is much larger than the wavelength of electrons.

Answer 13

resolution

Question 14

An organism of the genus
Staphylococcus is ________, while an organism of the genus Spirochaeta is ________.

Answer 14

spherical / coiled

Question 15

The cytoplasmic membrane could best be described as:

Answer 15

a highly selective permeability barrier

Question 16

The use of the Gram stain in microbiology is important because it differentiates:

Answer 16

Bacterial cells with different types of cell walls

Question 17

Cells move polar molecules across the cell membrane against a concentration gradient using:

Answer 17

energy and transport proteins

Question 18

Bacteria stain as gram-positive or gram-negative because of differences in the cell ____

Answer 18

wall

Question 19

You are given an electron micrograph of a bacterial cell. In the micrograph, you can clearly see 3 thin layers of different densities surrounding the cell. Based on the micrograph, you can infer that this cell is _________ and would appear __________ after application of the Gram stain procedure.

Answer 19

-gram negative
-pink

Question 20

A major function of prokaryotic gas vesicles is to :

Answer 20

confer buoyancy on cells by decreasing their density

Question 21

What is the biological function of endospores?

Answer 21

They enable organisms to endure extremes of temperature, drying and nutrient depletion.

Question 22

Although the inner leaflet of the gram-negative outer membrane is composed mainly of phospholipids, the outer leaflet of the outer membrane contains:

Answer 22

Lipopolysaccharides (LPS)

Question 23

When does endospore formation commence?

Answer 23

When bacterial growth ceases due to limitation of an essential nutrient

Question 24

You find endospores of a particular species. What is most likely true of this species?

Answer 24

It is a gram-positive bacterium

Question 25

The time interval required for the formation of two cells from one is called ________

Answer 25

generation time

Question 26

Turbidity measurements are commonly utilized for monitoring ___________.

Answer 26

planktonic cultures

Question 27

When attempting to determine viable cell counts of a heat-sensitive bacterial isolate, which cell counting method should be avoided?

Answer 27

Pour-plate method

Question 28

An agar plate for counting colonies and maximizing statistical validity should ideally contain ___________

Answer 28

25-250 colonies

Question 29

What temperature is most commonly used in autoclaves to sterilize growth media and other devices prior to experimentation?

Answer 29

121 degrees C

Question 30

Most mesophilic organisms can grow in a temperature range of _________

Answer 30

20-45 degrees C

Question 31

A bacterium possessing ____________ will produce O2 bubbles when placed in the presence of hydrogen peroxide.

Answer 31

catalase

Question 32

What form/s of oxygen is/are generally toxic to living organisms?

Answer 32

Superoxide, hydrogen peroxide, and hydroxyl radicals are all toxic

Question 33

How are serial dilutions generally made?

Answer 33

• when the appropriate viable count is unknown.
• based on powers of 10, although other serial dilutions factors are possible.
• to reach a suitable dilution while minimizing error.

Question 34

A medium containing known substances in precise amounts is known as a ____________ media.

Answer 34

defined

Question 35

The use of chemical agents directly on exposed body surfaces to destroy or inhibit vegetative pathogens is __________.

Answer 35

antisepsis

Question 36

A _______ agent is a chemical that inhibits bacteria from reproducing, but does NOT necessarily kill them.

Answer 36

bacteriostatic

Question 37

All microorganisms require ______________________________.

Answer 37

phosphorus, nitrogen, and sulfur