prokaryotes Flashcards

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1
Q

tree of life

A

bacteria, archaea, then eucarya branched off of archaea

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2
Q

prokaryotes lack membrane bound nucleus and organelles but have a

A

cell wall

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3
Q

cell wall contains

A

peptidoglycan

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4
Q

function of cell wall

A

maintains shape, provides protection, prevents osmotic bursting

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5
Q

2 types of cell walls

A

gram negative: thin peptidoglycan, lipopolysaccharide (endotoxin) and bilayered membrane, red

gram positive: thick peptidoglycan, single cell (plasma) membrane, purple

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6
Q

cell membrane/ plasma membrane

A

infolds for respiration/ photosynthesis

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7
Q

cell membrane function

A

selectively permeable; regulates movement in/out of cell
synthesis of cell wall components
assists w DNA replication
secretes proteins
contains flagella

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8
Q

what is cell membrane composed of

A

phospholipid bilayer, carbohydrates and proteins

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9
Q

capsule

A

coating of molecules external to the cell wall, made of sugars and/or proteins

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10
Q

capsule function

A

adhesion to substrate, cohesion, biofilms, protection against host immune system, camouflage from WBCs

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11
Q

centre of cell membrane is ____ and outer is ____

A

hydrophobic, hydrophilic

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12
Q

pili and fimbriae

A

when they are short an abundant the function is adhesion
when they are long and sparse the function is conjugation (joins one bacterium to another)

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13
Q

flagellum

A

allow bacteria to move, can rotate clockwise or anticlockwise, can be outside or inside the cell and when cell flexes moves in corkscrew motion

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14
Q

nucleoid

A

bacterial chromosome, single ring of DNA (haploid)

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15
Q

what exists in the cytoplasm

A

Ribosomal DNA

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16
Q

DNA on plasmids

A

-small circles of DNA, not essential for survival but advantageous in stressful conditions

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17
Q

bacillus shape

A

rods

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18
Q

coccus shape

A

balls

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19
Q

coccobacillus shape

A

ovals, somewhere inbetween coccus and bacillus

20
Q

spriochaete shape

A

squiggles

21
Q

endospores

A

large gram positive rods, thermostable and destroyed only by moist heat at 121 degrees for 15 mins, basis of sterilization standards

22
Q

why is mycoplasma an unusual bacteria

A

-lacks cell well
-smallest autonomous growing organism
-simple
-pleomorphic: resistant to lysis
-found on mucosal surfaces

23
Q

why is chlamydia an unusual bacteria

A

-energy parasite, stripped down genome, hijacks host metabolism

24
Q

rickettsia

A

bacteria, obligate intracellular parasites (requires a host to fulfil life cycle)
usually vector borne

25
Q

biofilms

A

mixed communities, embedded in a matrix, metabolic cooperation, resistance to removal

26
Q

ways biofilms communicate

A

homoserine lactones (quorum sensing)
electrical signals
genetic exchange

27
Q

two types of autotrophs

A

photoautotroph and chemoautotroph

28
Q

two types of heterotophs

A

photoheterotroph and chemoheterotroph

29
Q

photoautotroph energy source and carbon source

A

energy source: light
carbon source: CO2

30
Q

chemoautotroph energy source and carbon source

A

inorganic chemicals, CO2

31
Q

photoheterotroph energy source and carbon source

A

light, organic compounds

32
Q

chemoheyerotroph energy source and carbon source

A

organic compounds, organic compounds

33
Q

obligate aerobes

A

require O2 for respiration, growth

34
Q

facultative anaerobes

A

-can survive with or without oxygen, prefer O2 but can ferment organic molecules for ATP

35
Q

obligate anaerobes

A

poisoned by oxygen, use inorganic molecules or fermentation (organic molecules)

36
Q

aerotolerant anaerobes

A

grow anaerobically, but don’t die in presence of O2

37
Q

whats average generation time for prokaryotes (doubling time)

A

20 mins

38
Q

conjugation

A

plasmid gene transfer

38
Q

how do bacteria reproduce

A

asexual binary fission
one cell splits into two daughter cells

38
Q

what are some ways genetic variation occurs in bacteria

A

mutation, transformation, conjugation and transduction

39
Q

transformation

A

take up foreign DNA from environment

40
Q

transduction

A

gene transfer between cells by viruses (phages)

41
Q

extremophiles:

A

thermophiles; high temp
psychrophile; low temp
acidophile; acid
barophile; pressure
xerophile; dry
halophile; salt

42
Q

name some human applications

A

microbial leaching/ mining, fuel production, bioremediation, biotechnology

43
Q

first cellular life

A

cyanobacteria
utilized atmospheric elements to produce O2 which allowed for greater diversity of life

44
Q

compare prokaryote cell wall to fungi’s and plant cell’s

A

prokaryote cell wall; peptidoglycan, gram pos or neg
fungi cell wall; chitin
plant cell wall; cellulose

45
Q

general cell structure from out to in

A

surface filaments (pili and fimbriae, flagellum)
capsule
cell wall
plasma membrane
genetic material in cytoplasm (nucleoid; bacterial chromosome single ring of DNA (haploid), ribsomal DNA in cytoplasm, DNA on plasmids (not essential for survival))