Ubiquity of Bacteria

Question 1

_____________ are the most widely distributed organisms in the biosphere

Answer 1

Bacteria

Question 2

occur as part of the normal flora of humans and animals, where they occupy sites on surfaces such as the skin and intestinal tract.

Answer 2

Bacteria

Question 3

In humans it is estimated that the normal flora outnumber our own cells by approximately _____________

Answer 3

tenfold

Question 4

In plants they are found on ______________and in __________ on roots, where they form a symbiotic partnership with the plant to fix nitrogen from the atmosphere.

Answer 4

leaf surfaces; nodules

Question 5

We depend on _________________ to break down our sewage and waste

Answer 5

bacteria

Question 6

When ___________________ first studied bacteria in his laboratory, one of the first challenges was to devise a method to grow bacteria in culture so that populations could be separated into individual species.

Answer 6

Robert Koch

Question 7

It was found that bacterial cells would grow as visible, discrete ______________ on a ________________

Answer 7

colonies; solid medium

Question 8

A ________________ is a visible mass of cells usually resulting from the division of a single cell, and the number of cells in a single colony can exceed _____________.

Answer 8

colony; one billion

Question 9

a ______________ can arise from more than one cell, for example when a chain of cells such as _________________ grow on a _______________.

Answer 9

colony; streptococci; nutrient medium

Question 10

The cultivation of bacterial cells was vastly improved in Koch’s laboratory when ________________, the wife of an early coworker of Koch, suggested the use of ___________ as a ___________________.

Answer 10

Frau Hesse; agar-agar; solidifying agent

Question 11

could be added to rich broths to form a solid
medium on which isolated colonies would develop after
inoculation

Answer 11

agar

Question 12

The purity of cultures was further improved when __________________, a worker in Koch’s lab, introduced a
covered dish that protected the nutrient surface of media
from contamination by bacteria in the environment, especially the air.

Answer 12

R. J. Petri

Question 13

These methods were extremely important in the accomplishments of Koch’s lab because they provided a means for separating and culturing the pathogens
that they were studying, including anthrax caused by
____________________.

Answer 13

Bacillus anthracis

Question 14

Any bacterial cells that occur in the environment and are deposited on the agar medium or in the broth will subsequently undergo ____________________ to produce colonies or cause the broth to become turbid

Answer 14

cell division

Question 15

Bacteria form colorful blooms in sulfur hot
springs found in places such as ____________________

Answer 15

Yellowstone National Park

Question 16

When Robert Koch first studied bacteria in his laboratory, one of the first challenges was to ______________________________________________________________

Answer 16

devise a method
to grow bacteria in culture so that populations could be
separated into individual species.

Question 17

When Robert Koch first studied bacteria in his laboratory, one of the first challenges was to devise a method
to grow bacteria in culture so that populations could be
separated into individual species.

Initial approaches used _____________________________________________

Answer 17

pieces of vegetables such as potatoes and carrots, or the
addition of gelatin to meat broths.