Unit 4 Flashcards

(32 cards)

1
Q

Comparative Genomics

A

Using genomics to understand how organisms are related

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2
Q

Core genome

A

All of the genes shared by all of the strains of a species

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3
Q

Flexible genome

A

The genes that are not shared by all of the strains

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4
Q

Pan genome

A

All of the genes in the strains of a species

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5
Q

Endosymbiotic theory

A

Eukaryotic cells arose from the engulfment of prokaryotic cells by a larger cell - mitochondria and chloroplast

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6
Q

Evidence for the endosymbiotic theory

A

Both have outer and inner membranes, both contain ribosomes that resemble those of bacteria, both contain circular chromosomes

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7
Q

What is the last universal common ancestor

A

LUCA

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8
Q

Phylogeny

A

Evolutionary history of organisms - inferred based on genetic relatedness

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9
Q

Molecular clocks

A

Molecules that are used to measure the time of divergence of multiple organisms - molecules must have similar functions in all the organisms

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10
Q

Strain

A

Population of organisms that have descended from a single organism

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11
Q

The criteria in determining if two strains are the same in bacterial species:

A
  1. 16S rRNA sequence similarity: 16S rRNA sequences share 97%+ sequence similarity
  2. DNA hybridization: if >70% of their genomic sequences hybridize
  3. Average nucleotide identity: if their orthologous gene share 95%+ sequence similarity
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12
Q

Taxon

A

A set of microbes sharing a set of threshold similarity

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13
Q

When strains are found to define a new species, they must

A
  1. New name and characteristics must be published
  2. Strains must be saved in at least two culture collections
  3. A strain is designated as a Type Strain
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14
Q

Candidatus

A

If a new microbe discovered based on sequence data but no strains have been grown in pure culture

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15
Q

Microbial ecology

A

Microbes interact with other organisms and microbes interact with the environment

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16
Q

Population

A

Assemblages of similar organisms living in a common location

17
Q

Communities

A

Assemblage of populations living in a common location - support a variety of relationships among the members

18
Q

Symbioses

A

Interactions among organisms that involve a full range of positive and negative relationships

19
Q

Commensalism

A

A relationship in which one organism benefits from the association while the other is neither harmed nor helped - most common relationship among organisms

20
Q

Mutualism

A

Both partners gain from the association

21
Q

Parasitism

A

One organism adversely affects the other

22
Q

Obligate mutualist

A

Organism cannot survive separately - involves vertical transmission

23
Q

Primary symbionts

A

Relationship is obligate for both partners (one host needs the other) - microbe is present in all hosts

24
Q

Secondary symbionts

A

Relationship is obligate only for the microbe-microbe is only present in some hosts

25
What parts of the body are usally free of microbes? Where should microbes be?
Organs, blood, and muscles - microbes should be outside the epidermal layers
26
How does the GI tract stay free from microbes?
- Produces mucin (layer of glycoproteins) to keep the membrane moist to inhibit microbial attachment - High pH kills most microbes
27
What harbors largest microbial community in body?
Colon in large intestine
28
Does the gut microbome influences obesity
Yes, found through a mice expierment
29
Clostridium difficile
A pathogen that is a normal member of the gut microbiome
30
Gut microbiome helps prevent colonization by ....
pathogens but is in a delicate state of equilibrium
31
Why do microbes like the human oral cavity? How do you limit them?
Its lined with mucous which is an ideal enviornemnt. To help limit this saliva is rich in antibacterial enzymes, continuous mechanical flushing, continuous shedding of epithelial cells
32
What is dental plaque
multi-species of biofilm on teeth - fluoride makes calcium phosphate more resistant to decalcification