BIS 2C > Microbes > Flashcards

Microbes Flashcards

(44 cards)

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1
Q

Archaea

A

Definition: A domain of single celled organisms

Cell membranes:
fatty acids linked to glycerol by ether linkages, no peptidoglycan

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2
Q

Asexual reproduction

A

offspring arise from a single organism

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3
Q

Autoinducer

A
  • bacteria and archaea communicate with chemical signals (autoinducers) that are species specific or universal
  • initiate group behavior genes once concentration is high enough
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4
Q

Bacteria

A

Definition: A large domain of prokaryotic microorganisms

Cell membrane: They have a peptidoglycan layer in their cell walls (gram+ or gram-)

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5
Q

Binary Fission

A

1) asexual, rapid division
2) no cell cycle
3) no membrane-bound organelles

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6
Q

Biofilm

A

communities of organisms that are irreversibly bound to a substrate; they secrete extracellular polymers (slime)

It works as a means of communication between prokaryotic cells; enables them to function like a multicellular organism

Key features:

  1. Extracellular polysaccharide matrix
  2. Surface attachment
    - solid surface OR
    - soft tissues in living organisms
  3. Structural heterogeneity AND diversity (bacteria, archaea, protists, fungi, algae, etc.)
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7
Q

Chloroplast

A

An organelle bounded by a double membrane containing the enzymes and pigments that perform photosynthesis. Chloroplasts occur only in eukaryotes.

Also, organelles that work to convert light energy of the sun into sugars that can be used by cells

Origin: derived from endosymbiotic cyanobacteria

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8
Q

Conjugation

A

Bacteria and Archaea can directly exchange parts of their genome through a conjugation pilus (like a bridge). The transferred DNA is a plasmid.

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9
Q

Cyanobacteria

A
  • Photolithoautotrophic
  • Many can fix nitrogen
  • contain internal membrane system
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10
Q

Diploid

A

2n; 2 sets of chromosomes

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11
Q

Endosymbiosis

A

Explains the origins of eukaryotic cell organelles such as mitochondria and chloroplasts

evidence:

  1. mitochondrial/chloroplast size
  2. mitochondrial/chloroplast structure and presence of DNA; their DNA is similar in structure, size and shape to bacterial DNA
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12
Q

Eukarya

A

Nucleus present, linear DNA, haploid or diploid or more, membrane-enclosed organelles present, cytoskeleton, mitosis
features: metabolically limited,

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13
Q

Extremophile

A

organisms that can live in extreme conditions. freezing/boiling temperatures, acidic environments
also called halophiles, thermophiles, acidophiles

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14
Q

Gram Stain

A

reveals the complexity of bacterial cell walls & separates bacteria into two distinct groups.
gram negative= thin cell walls and an outer membrane
gram positive= have dense cell wall consisting of primarily peptoglycan

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15
Q

Halophile

A

a microorganism that grows in or can tolerate high salty conditions.

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16
Q

Haploid

A

n; has a single set of chromosomes

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17
Q

Heterotrophy

A

Carbon source is organic

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18
Q

Lateral Gene Transfer LGT

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A
  1. Conjugation - Bacteria and Archaea can directly exchange parts of their genome
  2. Transformation - Bacteria and Archaea can pick up DNA from their environment
  3. Transduction - Viruses can transmit DNA between hosts.

Similarities:

  • both create new genetic combinations
  • both may involve recombination

Differences (LGT):

  • only involves small part of genome
  • not reproduction
  • multiple mechanisms
  • can occur across large phylogenetic differences
19
Q

Mitochondria

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A

Facilitates aerobic cellular respiration in the cell.

Mitochondria arose from alpha-proteobacterium; all these bacteria are gram-

20
Q

Meiosis

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A

cell division that results in a reduction of ploidy

21
Q

Nitrogen Fixation

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A

Some cyanobacteria are able to fix atmospheric nitrogen and can convert it into a molecule to make available to other living organisms.

22
Q

Mitosis

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A

cell division that results in no reduction of ploidy

23
Q

Peptidoglycan

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A

bacteria membrane, cell wall; a special polymer of amino sugars

  • gram+: peptidoglycan is outside of cell wall
  • gram-: peptidoglycan is between plasma membrane and outer membrane of cell wall

only bacteria have peptidoglycan

24
Q

Phagocytosis

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A

The ingestion of bacteria or other material by phagocytes and amoeboid protozoans.

25
Photoautotroph
Organisms that carry out photosynthesis
26
Pathogenicity
• Pathogens are infectious agents that cause a disease (can be considered a subclass of parasites) • Pathogenicity = ability to enter a host and cause disease • Virulence = degree of pathogenicity • Note - not all parasites are pathogens but all pathogens are parasites Pathogenicity in Bacteria has evolved multiple times independently.
27
Photosynthesis
process where organisms use sunlight to synthesize foods from carbon dioxide and water. - generally involves green pigment chlorophyll and generates oxygen and carbohydrates as byproducts
28
Plasmid
a small DNA molecule that can replicate independently; and it is a small, circular chromosome distinct from main chromosome of a bacteria
29
Prokaryote
a microscopic single-celled organism that does not have a distinct nucleus with a membrane or membrane-bound organelles. Prokaryotes include bacteria and cyanobacteria.
30
Quorum Sensing
expression of group behavior genes as a result of density dependent interactions - seen in biofilms Group Behavior Genes: - Virulence - Antibiotics Production - Sporulation - Conjugation
31
Ribosomes
organelle that synthesizes proteins - ribosomes are conserved across life
32
rRNA
ribosomal RNA, used for protein synthesis in organisms. used to analyze microbes; all have RNA, LGT occurs, slowly evolve; links the amino acids together on the ribosome
33
Positive-sense RNA
- Single-stranded RNA ready for immediate translation into proteins - Polio, hepatitis, covid-19
34
Symbiosis
Symbiosis is an association between at least two different organisms in which at least one of them benefits 1. Mutualism: both benefit 2. Commensalism: one benefits, one does not gain or lose 3. Parasitism: one benefits, one suffers Eukaryotes - metabolically limited in their capabilities relative to archaea and bacteria - less able to "acquire" metabolic processes from other species via lateral gene transfer - eukaryotes can "acquire" more capabilities by engaging in symbiosis with archaea and bacteria
35
Spirochetes
- gram- bacteria - Motile - Axial filaments (modified flagella) - Many are pathogens
36
Thermophile
A type of extremophile that thrives at relatively high temperatures
37
Transduction
Viruses can transmit DNA between hosts
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SARS-CoV-2
name of the coronavirus that causes COVID-19. It is a positive sense RNA.
39
Universal Homology
shared features of all life that are evidence for a single origin
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Vertical Transmission
transmission from parent to child
41
Vibrio Fischeri
bioluminescence; glow because they have genes for producing light using a simple chemical redox reaction (one substrate is reduced and one is oxidized). (Fatty Acid Reductase and Flavin Oxido-reductase is recycled and when added with Liciferase and O2, gives light!)
42
Virion
``` A virion has a nucleic acid genome A protective protein coat (capsid) Some viruses contain a lipid envelope The virion is the form that can exist extracellularly and transfer to new hosts. ```
43
Virulence
how much damage you cause when you enter a host
44
Virus
Viruses are noncellular infectious agents that can replicate only inside the living cells of organisms using the existing cellular machinery and cause the synthesis of specialized elements (virions, virus particles) which can transfer the infection to new cells
BIS 2C
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