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Microbiology > Chapter 1 - Introduction to Microbiology > Flashcards

Chapter 1 - Introduction to Microbiology Flashcards

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1
Q

In what year did the CDC begin recording flu deaths for children?

A

2003

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2
Q

What are two reasons this year’s flu season is “odd”?

A
  1. The flu started earlier and does not seem to have reached its peak
  2. The flu is dominated by influenza B, which usually occurs later and at lower rates; this version is known to be deadlier for children and adolescents
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3
Q

Who received the Nobel Prize for discovering pencillin and even warned about antibiotic resistance?

A

Alexander Fleming

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4
Q

What is a microbe or microorganism?

A

An organism that is too small to visualize with the naked eye

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5
Q

Most microorganism are ____________________ and include all life forms other than plants and animals.

A

Microscopic

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6
Q

What is the average size of a microorganism?

A

Approximately 0.2 mm

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7
Q

True or false: all microbes are unicellular.

A

False. Most microbes are unicellular, but they can be multicellular; however, when multicellular, they lack highly differentiated tissues

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8
Q

What seems to have been an evolutionary invention of plants and animals alone?

A

Tissue differentation and organ specialization

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9
Q

When did microbal life originate?

A

Shortly after the formation of earth

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10
Q

How old do cosmologists believe earth to be?

A

Approximately 4.5 bilion years old

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11
Q

When did the earth become habitable for life?

A

Approximately 4.0 billion years ago once the earth cooled to temperatures less than 100 degrees celsius

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12
Q

How old are the oldest rocks?

A

3.8 billion years old

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13
Q

How old are the earliest known microbial fossils?

A

Approximately 3.4 to 3.5 billion years ago

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14
Q

What is the study of microscopic fossils called?

A

Micropaleontology

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15
Q

In Western Australia, rocks as old as ___________ billion years old were found, and it was believed that fossilized microbes were present in the rock; however, more recently, in the _________ ___________ _________ in Western Australia, it is believed that earliest life arose around 3.43 billion years ago.

A

3.46 billion years ago

Strelley Pool Formation

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16
Q

Why did researchers believe that the earliest signs of microbial life arose earlier than previously thought (i.e., the Strelley Pool Formation in Western Australia)?

A

Researchers outlined in “Microfossils of sulphur-metabolizing cells in 3.4-billion-year-old rocks of Western Australia” that microbial cells had been found based on “indicators of biological affinity,” including hollow cell lumens, carbonaceous cell walls enriched in nitrogen, taphonomic degradation, organization into chains and clusters, and δ13C values of −33 to −46‰ Vienna PeeDee Belemnite (VPDB).

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17
Q

Currently, research suggests that the earliest evidence of microbial life is _____________ billion years ago.

A

3.43 billion years ago

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18
Q

There are two fundamentally different types of cells: prokaryotic and eukaryotic. How does one distinguish them?

A

Eukaryotic cells have a membrane-bound nucleus whereas prokaryotic cell; it is the absence or presene of a membrane-bound nucleus is the only true defining feature

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19
Q

Which group of cells are generally specialized for rapid growth and maximal use of nutrients for increasing biomass? Prokaryotes and eukaryotes?

A

Prokaryotes

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20
Q

Which cell types are generally and intially specialized for predation on existing biomass? Prokaryotes or eukaryotes?

A

Eukaryotes

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21
Q

Although there are many exceptions, it is probably fair to think of the ____________________ as specialists at rapid growth at the expense of nutrients dissolved in the water that surrounds them. This has entailed the evolution of small, relatively simple cells with highly effective permease systems to take nutrients from a dilute solution, and a highly effiecient, tightly regulated _______________ to make the most of them.

A

Prokaryotes

Metabolism

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22
Q

What likely drove the multicellularity and complexity of eukaryotes?

A

Predartion of smaller, simpler prokaryotes

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23
Q

Are microbes rare or ubiquitous?

A

Ubiquitous

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24
Q

There are approximately 10__ human cells on the human body but approximately 10__ microbial cells!

A

1013 human cells

1014 microbial cells

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25
Q

What is the difference between a microbiota and a microbiome?

A

A microbiome is the collection of genomes from all the microorganisms found in a particular environment. Humans, plants, and other animals all have microbiomes; these can be generalised to their entire organism, or broken down into specific microbiomes for different locations on them. Microbiota, on the other hand, usually refers to specific microorganisms that are found within a specific environment. Microbiota can refer to all the microorganisms found in an environment, including bacteria, viruses, and fungi. This means that there are localised differences in the microbiota of each person, depending on where in the body the microbiota is collected from. In each person, their gut microbiota can be radically different to their skin microbiota – care needs to be taken when talking about where microbiota come from.

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26
Q

Collectively the microbal biomass is greater than or lesser than the macroscopic biomass by mass on earth.

A

Greather than

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27
Q

Bacteria, fungi, and viruses outnumber human cells in the body by a factor of ___ to ___.

A

10 to 1

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28
Q

In the human lungs, there are ____+ microbial species; in the gastrointestinal tract, there are _____ microbial species; and in the urogenital tract, there are ____ species of microbial species.

A

600

1,000

60

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29
Q

The tree of life is almost entirely ______________.

A

Microbial

30
Q

There are three major lineages of life on earth. What are they?

A

Eubacteria

Archaea

Eukarya

31
Q

Eukarya are most biochemically similar to Eubacteria or Archaea?

A

Archaea

32
Q

A ______________ __________ is a diagram that represents evolutionary relationships among organisms. They are hypotheses, not definitive facts.

A

Phylogenetic tree

33
Q

In a phylogenetic tree, more closely related species are closer or farther away from each other?

A

Closer

34
Q

Is Chlamydia more closely related to Escherichia or Clostridium?

A

Clostridium

35
Q

How are most phylogenetic trees constructed via modern technology?

A

Genome sequencing

36
Q

__________ is most often found in the human mouth; it is the primary colonizer of teeth, creating a biofilm that recruits more bacteria and ultimately leads to cavities.

A

Streptococcus

37
Q

What is “next generation” or “next gen” sequencing?

A

Next-generation sequencing (NGS), also known as high-throughput sequencing, is the catch-all term used to describe a number of different modern sequencing technologies. These technologies allow for sequencing of DNA and RNA much more quickly and cheaply than the previously used Sanger sequencing, and as such revolutionised the study of genomics and molecular biology

38
Q

Different areas of the body have different microbiomes, and it is believed that disruptions to these microbiomes can lead to ______________.

A

Illness

39
Q

Do the microbes in the gut of a premature infant change radically from day to day?

A

Yes, the microbes in the gut of a premature infant change radically from day 10 to days 16 through 21

40
Q

Prokaryotes inhabit a wide range of habitats. In what temperature and pH ranges can they be found?

A

Temperature range: -10 degrees to 120 degrees celsius

pH range: less than 1 to more than 10

41
Q

What probably defines the limits of life based on the kind of chemistry that characterizes life on earth?

A

The range in which prokaryotes can survive

42
Q

What is one of the biggest - if not the biggest - driving force for diversity among the microbes?

A

The immense range of the habitats in which they reside; ultimately this has resulted in evolutionary changes where prokaryotes have genes that lead to their ability to live in such environments

43
Q

Would removing all plants and animals destroy life on earth?

A

No; although the ecosystem would be affected, microbes are sufficient to maintain a sustainable global ecosystem as they did for several billion years

44
Q

Why are prokaryotes essential to all life on earth?

A

Because some catalyze transformations of chemical compounds essential to the sustainability of life

45
Q

What two specific reactions can prokaryotes accomplish that most eukaryotes are unable to do?

A

Fixation of inorganic nitrogen into organic nitrogen and denitrification of nitrate (organic nitrogen) into nitrogen gas (inorganic nitrogen)

46
Q

Briefly explain the nitrogen cycle.

A
47
Q

____________ ____________ is the process in which N2 in the atmosphere breaks and combines with other compounds to form organic molecules.

A

Nitrogen fixation

48
Q

_________________________ is the process in which organic nitrogen (e.g., nitrate) is broken down into nitrogen gas.

A

Denitrification

49
Q

Like all cells, microbes are mostly ____________.

A

Water

50
Q

Approximately how much water makes up microbes?

A

70%

51
Q

The dry weight of microbial cells consists mainly of _______________________ and ______________.

A

Macromolecules

Lipids

52
Q

What are macromolecules?

A

They are very large molecules with molecular weights above 10,000 Daltons with a polymeric structure

53
Q

What are lipids?

A

Lipids are smaller molecules with molecular weights under 1,000 Daltons; they are not polymeric in structure, and they are highly hydrophobic

54
Q

What are the three macromolecules?

A

Carbohydrates

Proteins

Nucleic Acids

55
Q

Macromolecules constitue more than ____% of the dry weight of microbial cells.

A

85

56
Q

Lipids constitute about ___% of the dry weiight of microbial cells.

A

10%

57
Q

Among the macromolecules, _________________ are the largest and most diiverse category.

A

Proteins

58
Q

There is something wrong with this figure. What is it?

A

The composition of a microbial cell is 70% water and 30% dry weight

59
Q

According to the textbook, there are four major macromolecule categories. What are they?

A

Proteins

Nucleic acids

Polysaccharides

Heteropolymers

60
Q

What are heteropolymers?

A

Macromolecules in which two different types of monomers are covalently combined

61
Q

What is the principle heteropolymer in E. coli?

A

Murein

62
Q

What is murein?

A

A heteropolymeric structure found in the cell wall of bacteria like E. coli that is composed of many short peptides and a polysaccharide core

63
Q

Another complex macromolecule or heteropolymer found in the cell walls of E. coli combines a polysaccharide with a lipid to form a ___________________________________.

A

Lipopolysaccharide

64
Q

The cytoplasm is a dense suspension of ______________________.

A

Ribosomes

65
Q

Why are there so many ribosomes in the prokaryotic cell?

A
  1. Because about 54% of the dry mass of the cell is protein
  2. Protein synthesis is slower than that of other macromolecules
66
Q

Approximately how many ribosomes are present in the average E. coli cell?

A

18,000

67
Q

The average E. coli cell has approximately ___ million proteins.

A

2 million

68
Q

What are most of the small molecules of a microbial cell?

A

Intermediates in biochemical pathways or monomeric precursors of macromolecules

69
Q

Why are small molecules so abundant if they make up only 5% of the dry weight of microbial cells?

A

Because they are so much smaller than the macromolecules, a very small mass of them consists of a very large number of molecules

70
Q
A

Microbiology (15 decks)

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