bacteria & archaea

prokaryote structure

• no nuclear membrane

• no membrane bound organelles

• almost all prokaryotes have a cell wall

three major cell shapes

• rods (bacillus)

• spheres (coccus)

• spiral (spirilla)

diplococci

pairs (cocci)

streptococci

chains (cocci)

staphylococci

grape clusters (cocci)

vibrio

curved rod (bacilli)

cell wall

• lies outside plasma membrane

• protects & prevents cell lysis (rupture)

• bacteria: w/ peptidoglycan (protein with a sugar on it)

• archaea: w/ other structural polysaccharides

gram + stain

purple

gram + structure

cell membrane → periplasmic space → thick cell wall (peptidoglycan)

cell wall gram +

contains techoic acid

gram - stain

pink or red

gram - structure

cell membrane → periplasmic space → thin cell wall (peptidoglycan) → periplasmic space → outer membrane (lipopolysaccharide)

cell wall gram -

does not contain techoic acid

capsule or slime layer

resists attack from immune system

fimbriae

hairlike protein that help cells stick to surface & each other

motility

many capable of movement

chemotaxis

move towards chemicals

phototaxis

move towards light

geotaxis (magnetotaxis)

moves towards magnetism

quoran sensing

bacteria can talk to each other

movement produced by

rotating flagellum protein fibers

invagination

in-folded plasma membranes

• used for aerobic cellular respiration or for O₂-producing photosynthesis

• compared to OUR mitochondria

under stress, some produce ____

dormant cells

• need heat and pressure to kill these

• endospores survive heat, drought for years

prokaryote DNA

one chromosome: circular DNA molecule w/ binding proteins (no histones for most)

histones

keeps DNA organizes, responsible for keeping the genes wrapped around the histone OFF

binary fission

• yields 2 identical cells

• short generation time if ideal & temp.

• logarithmic/exponential growth in #s

mechanisms for sexual reproduction in bacteria

1. conjugation

2. transformation

3. transduction

conjugation

a plasmis is moved by a pilus

transformation

the uptake by some of the bacteria of naked DNA

risk of transformation

could be viral

transduction

when a virus takes DNA from one bacteria to another

plasmids

extra tiny DNA rings w/ few genes

what do a lot of genes in plasmids code for?

antibiotic resistance

Griffith’s experiment

mixing heat-killed S cells and living R cells still killed. the mouse → rough cells uptook naked DNA that made a capsule

what carries DNA for transduction

bacteriophage virus

what does conjugation require

presence of F factor

what do F factor genes build

sex pilus (mating bridge)

where is F factor on chromosome

F-plasmid

F+

has plasmid w/ presence of F factor

R plasmids

genes for antibiotic resistance → can be transferred rapidly in this way

photoautotroph

energy source: light

carbon source: fixation from the air

chemoautotroph

energy source: inorganic compounds

carbon source: fixation from the air

photoheterotroph

energy source: light

carbon source: eating to get organic carbon

chemoheterotroph

energy source: organic compounds

carbon source: eating to get organic carbon