Question 1

The use of agar as the gelling agent in solid media was suggested by:

Accepted Answer

Angelina Hesse, the wife of a fellow microbiologist, suggested using agar as a gelling agent when she noticed that agar was being used to firm up jellies in her kitchen. This discovery revolutionized microbiology and allowed for the growth of bacteria on solid media. While scientists like Robert Koch and Louis Pasteur were instrumental in the development of microbiology, they did not specifically suggest using agar as a gelling agent in solid media. Ignaz Semmelweis was a physician who championed handwashing in medical settings. Richard Petri was a microbiologist who developed the petri dish.

Question 2

The first person to visualize individual microbes was:

Accepted Answer

Antoni van Leeuwenhoek was the first person to actually visualize individual microbes through the use of a microscope that he developed himself. Hooke also made observations of microorganisms, but he did not observe individual microbes, rather he observed the cellular structures or patterns of microorganisms. Pasteur, Lady Montagu, and Edward Jenner were all notable figures in the history of microbiology, but they did not visualize individual microbes for the first time.

Question 3

The presence of __________ on Mars today would increase the chance that microbial life exists there.

Accepted Answer

Liquid water is essential for life as we know it. If liquid water exists on Mars, it could potentially support microbial life. While there is evidence of water on Mars in the past, recent discoveries suggest that there may still be pockets of liquid water beneath the surface.

Question 4

How is most sterilization performed for the controlled study of microbes?

Accepted Answer

Autoclaving is the most commonly used method for sterilization in the controlled study of microbes. It uses high-pressure steam to kill microorganisms, including spores, and is effective for a wide range of materials and equipment. Boiling, pasteurization, filter sterilization, and irradiation may not achieve complete sterilization or may damage some materials.

Question 5

What type of gas do cyanobacteria produce for planet Earth?

Accepted Answer

Cyanobacteria are known to produce oxygen through photosynthesis, which is a major contributor to the Earth's atmosphere and supports most forms of life on Earth.

Question 6

Robert Koch's greatest accomplishment in the field of medical bacteriology was with:

Accepted Answer

Robert Koch's greatest accomplishment in the field of medical bacteriology was his discovery of the causative agent of tuberculosis, Mycobacterium tuberculosis. This discovery led to the development of effective treatments for the disease and contributed greatly to the field of microbiology.

Question 7

Which technique was developed to distinguish bacteria from human cells?

Accepted Answer

The Gram stain technique was developed to distinguish bacteria from human cells. This technique relies on the differences in bacterial cell walls, which can be stained and classified as either gram-positive or gram-negative, while human cells do not possess a cell wall and do not take up the stain. The other techniques listed are not specifically used to distinguish bacteria from human cells.

Question 8

What are the primary producers of major food webs?

Accepted Answer

The answer of What are the primary producers of major...

Question 9

Which century is known as the golden age of microbiology?

Accepted Answer

The nineteenth century is known as the golden age of microbiology because many significant discoveries were made during this time, including the discovery of microorganisms, the establishment of basic principles of bacteriology, and the development of techniques for culturing and identifying bacteria. Notable microbiologists from this era include Louis Pasteur, Robert Koch, and Ignaz Semmelweis.

Question 10

The first genomes to be sequenced were those of:

Accepted Answer

The first complete genome to be sequenced was that of a virus, specifically bacteriophage MS2, in 1976.

Question 11

A human body contains __________ times as many microbes as it does human cells.

Accepted Answer

The human body contains approximately 10 times as many microbial cells as human cells, primarily bacteria in the gut.

Question 12

Who developed the concept of medical statistics?

Accepted Answer

Florence Nightingale is credited with developing the concept of medical statistics during her work as a nurse during the Crimean War. She used statistical analysis to show the importance of sanitation in preventing disease and improving public health.

Question 13

Bacteria that produce enzymes used in the polymerase chain reaction were isolated from:

Accepted Answer

Bacteria that produce enzymes used in PCR are often found in extreme environments such as hot springs, where they have evolved to survive in high temperatures.

Question 14

What percentage of microbes in our biosphere can be cultured in the laboratory?

Accepted Answer

Only a small fraction of microbes in our biosphere can be cultured in the laboratory, estimated to be less than 1%. This is due to the fact that many microbes have specific growth requirements that cannot be easily replicated in laboratory conditions, or they may have symbiotic relationships with other organisms that are difficult to mimic.

Question 15

The eukaryotic predators of the microscopic world are:

Accepted Answer

Protists, which are single-celled eukaryotes, are known to be predators in the microscopic world. They can feed on bacteria, algae, and other protists. Viruses are not considered predators as they cannot actively consume or digest other cells. Bacteria, cyanobacteria, and algae are prokaryotes and therefore cannot be considered eukaryotic predators.

Question 16

How did European invaders to North America kill much of the native population?

Accepted Answer

European invaders brought with them diseases, such as smallpox, that the native population had no immunity to. This led to devastating epidemics that killed between 50% - 90% of native populations in various regions.

Question 17

All of the following have been found in mummies and tomb art EXCEPT:

Accepted Answer

Prions, which are infectious proteins responsible for diseases such as Creutzfeldt-Jakob disease, have not been found in mummies or tomb art. On the other hand, archaeological evidence has shown the presence of tuberculosis, leprosy, polio, and smallpox in ancient civilizations.

Question 18

Suppose Pasteur's swan-necked flasks containing boiled broth became cloudy 24 hours after boiling. Which choice could best explain the turbidity or cloudiness in the broth without supporting spontaneous generation?

Accepted Answer

Endospores are highly resistant structures that can survive boiling and only begin growing when the conditions are suitable. This explanation is supported by the fact that the swan-necked flasks would have prevented new organisms from entering the broth, thus eliminating the possibility of spontaneous generation.

Question 19

Which of these is currently the number one cause of human mortality?

Accepted Answer

The answer of Which of these is currently the number...

Question 20

Which of these groups are considered to be microbes but NOT considered to be cells?

Accepted Answer

The answer of Which of these groups are considered to...

Quiz 1: Microbial Life: Origin and Discovery