lecture 13- prokaryotes Flashcards

1
Q

what are the traits that archae has in common with bacteria

A

lack of nuclear envelope
lack of membrane bound organelles
circular chromosome

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2
Q

what traits that archae has in common with eukaryotes

A

peptidoglycan in cell wall
histones used to unravel genes

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3
Q

what are traits that are specific to archae

A

ability to grow at temperatures above 100 celsius (extremophiles)
cell membranes have membrane lipids

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4
Q

what are characteristics of bacteria and archae (prokaryotes)

A

unicellular
no nucleus
one circular chromosome
most have cell wall
asexual reproduction
ribosome structure is different than eukaryotes

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5
Q

what is the size of prokaryotes

A

0.5 to 5.0 um

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6
Q

what is a chemotroph

A

organism that gets its energy from chemical bonds
organic compounds or inorganic substrates

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7
Q

what is a phototroph

A

organism that gets its energy from the sun

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8
Q

what is an autotroph

A

organism that gets its carbon from the air

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9
Q

what is a heterotroph

A

organism that gets its carbon from organic compounds (existing molecules that it breaks down)

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10
Q

what is an obligate aerobe

A

they need oxygen for cellular respiration

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11
Q

what is a facultative anaerobe

A

will use oxygen if present but can also grow without it (fermentation)

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12
Q

what is an obligate anaerobe

A

cant grow with oxygen
will die

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13
Q

how do prokaryotes reproduce

A

by binary fission

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14
Q

why dont prokaryotes take over the earth since they divide so fast

A

competition between themselves
lack of ressources

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15
Q

what are endospores

A

dormant cell/spore that can survive harsh conditions and will revive when the conditions get better

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16
Q

what are methanogens

A

release methane as byproduct of cellular respiration
anaerobic environments (bottom of lakes/swamps or intestine tracts)

17
Q

what are extreme halophiles

A

archae that can live in extremely saline environments (dead sea)
salt dehydrates cells so not many organisms can survive these conditions

18
Q

what are extreme thermophiles

A

grow in hot environments 45-104 celsius
(hot springs and deep sea vents)

19
Q

what are archae’s cell wall made of

A

proteins, glycoprotein (sugar and protein) or carbohydrates

20
Q

what are the arrangements of strepto, staphylo and spirilla colony shape

A

strepto: chains
staphylo: clumps
spirilla: spiral/squiggly

21
Q

where is the circular dna of prokaryotes located

A

in the nucleoid region

22
Q

what do plasmids contain

A

genes that are useful in special circumstances

23
Q

how are plasmids transmitted

A

bacterial conjugation/sex

24
Q

how does bacterial conjugation happen

A

happens when two bacterial cells are temporarily joined
via sex pilus

25
Q

characteristics of plasmids

A

circular
self replicating

26
Q

why dont antibiotics cause resistance

A

they create an environment where bacterias containing antibiotic resistant plasmids/genes have no competition by eliminating non-resistant bacteria

27
Q

what are the ecological roles of bacteria on earth

A

decomposers (major role)
mutualistic symbionts
producers
pathogens

28
Q

what are the benefits of symbionts in humans

A

produce essential vitamins (e. coli)
prevent pathogens from invading (produce chemicals that are toxic to other bacterias)
prevent infections (skin and mucous symbionts)

29
Q

how do bacteria help plants

A

they “fix” nitrogen (into ammonium or nitrate ions) so that the plants can use it for growth (nitrogen gas is unusable)
bacteria benefits from the good environment and plant can grow

30
Q

what are the specialized cells in cyanobacteria where nitrogen fixation happens called

A

heterocysts

31
Q

what organisms produce antibiotics

A

fungi, bacteria

32
Q

why do fungi and bacteria produce antibiotics

A

because they cant move so they compete with the organisms around them, they release antibiotics to kill the others to get all the ressources to themselves