MCB Chapter 1 study guide Flashcards

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1. What are microbes (microorganisms) small lifeforms? Or: what sets a microbe apart from other organisms?

-Tiny living things that are found all around us and are too small to be seen by the naked eye: they live in water, soil, and in the air. The human body is million of these microbes too.

- Microbes are the oldest form of life, and although they are very small in size. Together they form the largest living mass on earth .


Aristotle (382-322) BCE

He came up with the Theory of Spontaneous generation. This theory proposed that: Life can start from non-living sources

-In a flask: dirty clothes, grains, legumes

- Wait for 21 days... and you could produce a mice.


Jenifer Doudna (1964-

The work of her has greatly improved the precision of editing genomes by adapting pathway that occurs in bacteria to use in the laboratory .


Rosalind Franklin (1920-1958)

was the first to generate an x-ray crystallography image to show DNA, the genetic material of all living organisms, consist of the intertwined helices.



used focusing devices to make both microscopes and telescopes. He is not only pointed the lens construction toward the sky but also downward


Robert Hooke (1635-1703)

was a microscopist - is the first one who looks at the microorganism and describes cells, the smallest units of microorganism. And was a microscopist who published the first book on really small things called "Micrographia"(1665)


Hans and Zacharias Jansen (1590-1632)

Lenses in tube can enlarge things


Edward Jenner (1749-1823)

-Father of immunization

-Discovered that milkmaids who had contracted cowpox didn’t catch the much more dangerous smallpox, and he experimented by taking the pus from the blisters of cowpox-infected milkmaids and scratching them on the skin of his gardener’s son. He then exposed the boy to a smallpox patient a while later and reported that the boy appeared immune to the deadly disease.


Robert Koch (1843–1910)

was a strong proponent of the “germ theory of disease”. He formulated what’s now known as “Koch’s Postulates”: a set of steps to be followed to show that a particulate microorganism causes a disease.

Koch’s postulates:

  1. The suspected pathogen must be present in every organism (plant, animal, human) that has the disease, and absent from healthy ones.
  2. The pathogen must be isolated in pure culture.
  3. The pathogen thus isolated, must cause the disease upon introduction into a healthy animal.
  4. The pathogen must then be re-isolated in pure culture and shown to be the same as the original.

Antonie van Leeuwenhoek (1632–1732)

A new method for preparing lenses and he developed the first real microscope, he then discovered microorganism can sometimes move " wee animacules" that he use to describe small animals.

-Came up with a new method of preparing lenses, and he became the first to notice that some of these little things were alive. He called the microorganisms he saw “wee animalcules”.


Joseph Lister (1827–1912)

As a result of the fact that diseases could be proven to cause disease, Joseph Lister (1827-1912) starting using a chemical to disinfect wounds and surgical incisions, dramatically lowering the rate of infections and death.


Lynn Margulis (1938–2011)

As it turns out, there is significant evidence that supports the endosymbiotic theory formulated by Lynn Margulis (1938-2011) which proposes that certain eukaryotic structures are derived from engulfed prokaryotes


Louis Pasteur (1822–1895)

finally dispelled the theory of spontaneous generation by using special flasks that allowed air in, but no dust and associated microbes. He did carefully controlled experiments using “the scientific method” (explained below) that once and for all showed that life did not come from nothing


Francesco Redi (1626–1697)

Performed experiments with meat in containers that were left open and exposed to flies, closed, or covered with gauze. He showed that maggots only developed on the meat if the flies had gotten to it. This was a refutation of the theory, but it was considered an exception


Lazzaro Spallanzani (1729–1799)

was an Italian biologist who challenged the idea of spontaneous generation. In 1765 he published a rebuttal of the idea that microbes could self-generate. He showed that if a container with microbes was boiled for an hour, no re-growth occurred in the container, as long as it remained sealed


5. What are two reasons that helminths (worms are studied in Microbiology) even though they are microscopically large?

Ex of helminths: flatworms and round, multicellular

Because they can cause disease in people, and they have microscopic life stages (it is contact with the microscopic life stages that may result in the transmission of disease).


6. How can you distinguish a protozoan from a fungus?

Fungi are eukaryotic organisms (this means that they *do* have a nucleus) and can occur as single-celled organisms (yeasts) or multicellular organisms (mushrooms and molds).

Protozoa are single-celled eukaryotic organisms that live either freely in the environment or as parasites of other organisms.


a. Why are viruses not considered alive?

Viruses are not alive because they lack some of the key characteristics of living organisms, such as a cytoplasm of organelles. They cannot carry out cellular functions such as metabolism and homeostasis. ... Viruses are included in the study of biology because they are active inside living cells.


What characteristics of life do viruses have, and which do they not?

Viruses are lifeforms that do not have cells, means have no cytoplasm or cellular organelles, do not have their own metabolism or enzymes to make their own proteins.

They are obligate parasites, which means that they can only replicate inside other cells.

Living characteristics of viruses include the ability to reproduce – but only in living host cells – and the ability to mutate.



-Prokaryotic, unicellular

-Size: small

Cell wall what type: Have cell wall

-Major characteristics: Often found in extreme environments, not known to cause disease in people



-prokaryotic, unicellular

Size: small

Cell wall what type: peptidoglycan

Major characteristics: can cause disease in people, grow through binary fission, nutritionally diverse



eukaryotic, unicellular -or multicellular

size: second-largest, because
they can be multicellular

Cell wall what type: chitin and

Major characteristics: are plant pathogen, absorb
organic material from the



eukaryotic, multicellualar

Size: largest

Cell wall what type: No cell wall

Major characteristics: Eggs/cysts are unicellular and
microscopic. Some can cause
disease in people.



eukaryotic, unicellular

Size:third-largest because they are always unicellular

Cell wall type: No Cell wall

Major Characteristics: Most can move, some cause disease in people, can be parasitic or independent- living




Not prokaryotic/eukaryotic, acellular ( No cell )

Size: smallest

Cell wall what type: No cell wall

Major characteristic: Obligate parasites (they must grow
inside cells), they cannot make their
own ATP, and they do not have
ribosomes to make proteins.