L13 Bacteria & Archaea pt 2

Question 1

how are prokaryotes classified

Answer 1

by dividing them into classes, and further into species

Question 2

what are 6 groups of bacteria

Answer 2

• proteobacteria
• green bacteria
• cyanobacteria
• gram-positive bacteria
• spirochetes
• chlamydia

Question 3

what is the key distinguishing feature of the different groups of bacteria

Answer 3

composition of the cell wall

Question 4

what is the most diverse group of bacteria

Answer 4

proteobacteria

Question 5

describe gram-negative bacteria

Answer 5

-purple sulfur bacteria (their colour is caused by a specific type of chlorophyll)
-photoautotrophic or photoheterotrophic

Question 6

describe free-living gram-negative proteobacteria

Answer 6

• chemoheterotrophs
• includes intestinal bacteria
• some of these cause diseases (bubonic plague, gonorrhea, gastroenteritis, dysentery)

Question 7

What is a type of green bacteria? describe this

Answer 7

• gram-negative photosynthetic bacteria
• photoautotrophic are found in hot springs
• photoheterotrophic are found in marine and high salt environments
• distinctive chlorophyll compared to plants
• don’t release oxygen during photosynthesis

Question 8

describe cyanobacteria

Answer 8

• include blue-green algae and gram-negative aerobic photosynthetic prokaryotes
• responsible for oxygen-based life on earth
• some make colonies, have specialized cell types (heterocysts for nitrogen fixation)

Question 9

what is the most morphologically diverse group of bacteria

Answer 9

cyanobacteria

Question 10

describe gram-positive bacteria

Answer 10

• give positive result on gram stain test
• thicker peptidoglycan on outside
• mainly chemoheterotrophs
• has many pathogenic species
• some species are beneficial

Question 11

bacillus anthracis

Answer 11

rod-shaped bacteria causing anthrax

Question 12

staphylococcus

Answer 12

sphere shaped bacteria causing:

• food poisoning
• toxic shock syndrome
• pneumonia
• bacterial meningitis

Question 13

streptococcus

Answer 13

• sphere-shaped bacteria causing:
• strep throat
• pneumonia
• necrotizing fasciitis

Question 14

lactobacillus

Answer 14

Rod shaped bacteria using lactic acid fermentation to make pickles, kimchi, sauerkraut, yogurt

Question 15

describe spirochetes, what type of bacteria are they?

Answer 15

• +/- species
• propelled by rotation of flagella (movement in thick mud or sewage)
• found in human mouth, termite intestines that digest cellulose
• some pathogenic species (e.g. syphilis)
• type of gram-negative bacteria

Question 16

describe chlamydias, what type of bacteria are they?

Answer 16

• obligate intracellular pathogens of humans and animals
• type of gram-negative bacteria
• cause STIs and respiratory infections
• cell walls lack peptidoglycan
• significantly reduced genome size compared to other bacteria

Question 17

why are deinococcus radiodurans unique

Answer 17

• tolerant to radiation
• can break down radioactive waste

Question 18

why are thermus aquaticus unique

Answer 18

• tolerant to high temperatures
• DNA polymerase is very heat stable
• PCR techniques to make copies of DNA sequences for genetic engineering

Question 19

why are archaea unique

Answer 19

• features similar to bacteria (prokaryote, chromosomes, ribosomes) and eukaryotes (histones, enzymes)
• unique features (membranes and protein synthesis)

Question 20

what are the main phyla of archaea

Answer 20

euryarchaeota, crenarchaeota, korarchaeota, thaumarchaeota

Question 21

what are similarities between archaea and bacteria

Answer 21

• do not contain nucleus or membrane-bound organelles
• circular DNA
• same ribosome size (70S)
• can grow at temperatures of 80C +
• operons in DNA, introns in most genes
• fixate nitrogen, complete chemoautotrophy

Question 22

what are differences between bacteria and archaea

Answer 22

• membranes of bacteria are ester-linked
• bacteria completes photosynthesis with chlorophyll
• bacteria are sensitive to antibiotics
• histone proteins are in archaea cells
• archaea can complete methanogenesis

Question 23

what are 3 types of euryarchaeota

Answer 23

methanogens, halophiles, extreme thermophiles

Question 24

describe methanogens

Answer 24

• methane producing
• living in low oxygen environments
• anaerobic in organs of animals (stomachs, rumen)
• swamps, lakes, marshes, sewage works

Question 25

describe halophiles

Answer 25

- live in highly salted environments - are aerobic chemotrophs - get energy from sugars, alcohols, amino acids, or light as secondary energy source

Question 26

describe thermophiles

Answer 26

- live in extremely hot environments like hydrothermal vents and hot springs - tolerate temps between 70C and 95C

Question 27

what are 3 types of crenarchaeota

Answer 27

extreme thermophiles, psychrophiles, mesophiles

Question 28

describe extreme thermophiles (cren.)

Answer 28

- higher optimal temp range than euryarchaeota - sulfur dependent

Question 29

describe psychrophiles

Answer 29

- love cold - thrive at temp between -10C to -20C - found in arctic and antarctic oceans

Question 30

describe mesophiles

Answer 30

marine plankton in cool waters

Question 31

describe korarchaeota

Answer 31

- Recognized only by sequences in DNA samples - Found in hydrothermal environments but have never been isolated and cultivated in lab - Nothing known about their physiology

Question 32

describe thaumarchaeota

Answer 32

- initially known as mesophilic crenarchaeotes - likely most abundant cells in oceans - chemoautotrophs using ammonia

Question 33

what is the TACK acronym

Answer 33

Thaumarchaeota Aigarcheota Crenarchaeota Korarchaeota

Question 34

what is the human microbiome

Answer 34

- prokaryotes that live on and within human body - estimated that bacterial and archaeal cells outnumber human cells by 10 to 1 ratio but new research suggests ~1 to 1 ratio - bacterial and archaeal genes outnumber human genes by 100 to 1

Question 35

when are intestinal bacteria beneficial

Answer 35

- break down food - secrete vitamins, biomolecules into colon for nutrient absorption - makes molecules that signal other systems such as immune and nervous system

Question 36

compare african microbiome to western microbiome

Answer 36

- plant-based vs. sugar and fat based - dominated by bacteroidetes vs firmicutes - african microbiome can digest plant fiber

Question 37

what are prokaryotes important to study

Answer 37

- medicine - ecosystem processes - talents - biotechnology, bioprocessing, biomimicry - research into human microbiome and human interactions

Question 38

describe the evolutionary history of prokaryotes

Answer 38

- TACK - network as opposed to tree - evolution of bacteria and archaea seen as important part of evolution of eukarya