9/18 Prokaryotes Flashcards

1
Q

Prokaryotes:
* Exist almost everywhere, including places where _____________________
* Biomass outweighs all eukaryotes combined by at least __________

A
  1. eukaryotes cannot
  2. 10x
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2
Q

Prokaryotes:
Functions:
* Break down organic material in dead plants and animals
* Release ________ used by plants
* Make ________________ available to most life forms
* O2 in atmosphere came from photosynthetic __________

A
  1. CO2
  2. Nitrogen(N)
  3. bacteria
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3
Q

Prokaryotes:
Both __________________________ to humans
* Important to produce some _____________
* Chemical reactions in industry
* Used for pharmaceutical products
* Bioremediation of _______________ sites

A
  1. beneficial and harmful
  2. foods
  3. polluted
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4
Q

3 Domains of LIFE:
1. _________
2. _________
3. _________

A
  1. Bacteria
  2. Archaea
  3. Eukarya
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5
Q

Shared Characteristics of the 3 domains:
1st tick:
1. _________
2. _________
3. _________

A

1.DNA
2.Ribosomes
3.Plasma membrane

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6
Q

Shared Characteristics of the 3 domains:
2nd tick:
1. _________
2. _________
Prokaryotes lack these

A

1.Nucleus
2.Membrane bound organelles

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7
Q

Prokaryotic genomes:
* Prokaryotes genomes ________, simpler than eukaryotes
* 1/1,000 as much DNA as a eukaryote
* 5,000 genes vs. 50,000 in eukaryotes
* DNA condensed in nucleoid region of cytoplasm
* Similar to nucleus but _________________________
* Single, circular, double-stranded DNA chromosome

A
  1. are smaller
  2. no membrane
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8
Q

Prokaryote Reproduction:
* Prokaryotes grow and adapt ____________________
* Reproduce ________________ via binary fission
* No ______________________
* A single cell in favorable conditions will produce a
colony of offspring (1012 cells in 24 hrs!)

A
  1. rapidly
  2. asexually
  3. meiosis
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9
Q

Binary Fission steps:
1. Circular chromosome ________
2. Copies of ____ separate as cell enlarges
3. Plasma membrane and cell wall _________ into two cells

A
  1. replicates
  2. DNA
  3. separate
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10
Q

When conditions unfavorable, some bacteria form endospores
(____________ condition)

Cytoplasm and chromosome dehydrate Encased by 3 layers

Resistant to
1. _____________
2. Drying
3. _____________
4. Antibiotics
5. Various chemical
disinfectants

Can survive for _________________
years in this dormant state!

A
  1. dormant
  2. heat
  3. radiation
  4. thousands
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11
Q

Genetic Diversity?

  • ___________________________ but…
  • Several mechanisms to combine genes between
    individuals
  • These are called horizontal gene exchange
  • Allows genetic transfer between prokaryotes
A
  1. lack meiosis
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12
Q

Genetic Diversity:
1. Transformation: a cell absorbs and integrates
fragments of _________ from the _________________
2. Conjugation: one cell directly transfers genes to
_________________________
3. Transduction: ____________ transfer genes between
prokaryotes

A
  1. DNA from the Environment
  2. another cell
  3. viruses
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13
Q

Domain Bacteria:

Bacteria differentiated with Gram stain
* Gram-positive
– Retain dyes (purple and red)
– Appear _____________
– ___________ cell wall
* Gram-negative
– Only retain red dye
– Appear _____________
– ________ cell wall

A
  1. purple
  2. thick
  3. pink/red
  4. thin
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14
Q

Gram-positive (Gram+) bacteria – ______________, thicker
cell walls, large amounts of peptidoglycan in a thick cell wall

A
  1. simpler
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15
Q

ram-negative (Gram-) bacteria – __________________,
less peptidoglycan, thinner cell wall
* Outer membrane ______________ cell wall
* Contains lipopolysaccharides (carbohydrates
bonded to lipids)

A
  1. more complex
  2. outside
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16
Q

Among pathogenic bacteria:
* Gram- more ____________________ than Gram+
* Outer membrane protects ____________ pathogens from
defenses (immune system) of their hosts
* Gram- bacteria more ____________ than Gram+ to antibiotics
* Outer membrane impedes entry of antibiotics

A
  1. threatening
  2. Gram-
  3. resistant
17
Q

Bacteria also differentiated by three basic shapes
1. _______– round
2. ________- rod
3. ________- spiral

A
  1. Cocci –
  2. Bacilli
  3. Spirilli
18
Q

Domain Bacteria
* Outnumber all other organisms on Earth
* _________________ species identified
* Habitats range from land, aquatic, to parasitic
* Remarkable metabolic diversity allows them to live almost anywhere
* Biomass outweighs all eukaryotes combined by at least ________

A

1.10,000
2. 10x

19
Q

Significance to Humans
* Some cause __________________________
– MRSA
– Bacterial meningitis

A
  1. disease
20
Q

Significance to Humans
* Provide ___________, chemicals and _______________
– Fermented meats (salami)
– Lactobacillus and Streptococcus (both bacteria) produce yogurt
* Geochemical processes (carbon and nitrogen
cycles)
– Nitrogen fixation
– Photosynthesis

A
  1. food and medicines
21
Q

Cyanobacteria
* _______________ bacteria
* _________________________
* Called “blue-green algae”
* May be responsible for _________________________ into the
primitive atmosphere (3.5bya)
* Photosynthetic and unicellular or colonial
* Common in freshwater, moist soils, oceans, bare rock

A
  1. Gram-
  2. Photosynthesize
  3. introducing oxygen
22
Q

Cyanobacteria
* Produce hepatotoxins and neurotoxins
* Neurotoxins are highly toxic
* Hepatotoxins damage ___________
* Low, chronic exposures may
cause liver cancer

A
  1. liver
23
Q

Domain Archaea
Formerly considered _____________________
* Unique rRNA base sequences
* More closely related to ________________________
* _________________________ environments

A
  1. bacteria
  2. eukarya than bacteria
  3. extreme environments
24
Q

Archaea Structure and Function
* Plasma membranes have unusual lipids
* Diverse cell wall types (polysacharride, protein, or absent)
* Some are methanogenic (make methane)
* Anaerobic areas (swamps and marshes)
* Intestinal tracts of animals
* Most are chemoautotrophs
* Inorganic compounds (no carbon) to produce
energy
* None are _________________________
_____________________ to cause infectious disease

A
  1. photosyntheic
  2. not known
25
Q

Types of Archaea:
Methanogens
* Anaerobic environments
(without ________________)
* Produce methane from hydrogen
gas and carbon dioxide

A
  1. oxygen
26
Q

Types of Archaea
Halophiles
* Require ____________
concentrations for growth (12-15%)
* Great Salt Lake, Dead Sea,
hypersaline soils
Thermoacidophiles
* Reduce sulfides and survive best at
temperatures above 80oC
* pH of 1 or 2

A
  1. high salt
27
Q

Viruses (not a __________________)
* Segments of DNA or RNA
wrapped in protein coat
* Not considered __________
1. Cannot ___________on their own
(hijack host’s cells to replicate)
2. ______________ (no cells ,
organelles, or cytoplasm)
3. Do not grow
4. No _____________(requires a host)
* Viruses come from host genes
that somehow ____________
host & acquired a protein coat
* Parasitic chemica

A
  1. prokaryote
  2. alive
  3. reproduce
  4. acellular
  5. metabolism
  6. escaped