15

Question 1

Phylogeny

Answer 1

evolutionary history of species and how they’re related.

Question 2

Three-Domain System

Answer 2

classification dividing life into Bacteria, Archaea, Eukarya.

Question 3

Metagenomics

Answer 3

sequencing DNA from environmental samples to identify unculturable microbes.

Question 4

Bacteria

Answer 4

prokaryotes with peptidoglycan cell walls and huge metabolic diversity.

Question 5

Archaea

Answer 5

prokaryotes without peptidoglycan; often extremophiles; no known pathogens.

Question 6

Proteobacteria

Answer 6

major Gram-negative group including photoautotrophs, heterotrophs, and many pathogens.

Question 7

Alphaproteobacteria

Answer 7

subgroup containing ancestors of mitochondria.

Question 8

Betaproteobacteria

Answer 8

subgroup including soil nitrifying bacteria.

Question 9

Gammaproteobacteria

Answer 9

includes E. coli, Salmonella, Vibrio, Yersinia pestis.

Question 10

Deltaproteobacteria

Answer 10

includes predatory Bdellovibrio.

Question 11

Epsilonproteobacteria

Answer 11

includes ulcer-causing Helicobacter pylori.

Question 12

Neisseria gonorrhoeae

Answer 12

Gram-negative pathogen causing gonorrhea.

Question 13

Helicobacter pylori

Answer 13

bacteria causing stomach ulcers.

Question 14

Bdellovibrio

Answer 14

bacteria that drill into and kill other bacteria.

Question 15

Chlamydias

Answer 15

obligate intracellular parasites lacking peptidoglycan walls (e.g., Chlamydia trachomatis).

Question 16

Spirochetes

Answer 16

spiral bacteria moving by internal filaments (e.g., Borrelia causing Lyme disease).

Question 17

Cyanobacteria

Answer 17

photoautotrophs producing oxygen; ancestors of chloroplasts.

Question 18

Great Oxygenation Event

Answer 18

atmosphere-changing oxygen rise caused by cyanobacteria.

Question 19

Deinococcus radiodurans

Answer 19

extremely radiation-resistant bacterium.

Question 20

Gram-positive bacteria

Answer 20

large group including soil decomposers and pathogens; many produce antibiotics. (Bacillus, Clostridium, Streptomyces, Actinomycetes, Mycoplasmas)

Question 21

Actinomycetes

Answer 21

soil bacteria forming colonies; major source of antibiotics.

Question 22

Streptomyces

Answer 22

soil bacteria producing natural antibiotics.

Question 23

Bacillus anthracis

Answer 23

Gram-positive pathogen forming endospores; causes anthrax.

Question 24

Clostridium

Answer 24

Gram-positive anaerobes forming endospores (botulism, tetanus, C. diff).

Question 25

Mycoplasmas

Answer 25

smallest known cells; lack cell walls.

Question 26

Archaeal extremophiles

Answer 26

archaea thriving in extreme heat, salt, acidity, or anaerobic conditions.

Question 27

Halophiles

Answer 27

archaea living in extremely salty environments.

Question 28

Thermophiles

Answer 28

archaea living in very hot environments.

Question 29

Methanogens

Answer 29

archaea producing methane in oxygen-free environments.

Question 30

Asgard archaea

Answer 30

archaeal group closely related to eukaryotes (eukaryotic ancestor).

Question 31

Lokiarchaeotes

Answer 31

subgroup within Asgard archaea linked to origin of eukaryotes.

Question 32

Symbiosis

Answer 32

close long-term relationship between two species.

Question 33

Host

Answer 33

larger organism in a symbiosis.

Question 34

Symbiont

Answer 34

smaller organism living in or on the host.

Question 35

Mutualism

Answer 35

both partners benefit.

Question 36

Parasitism

Answer 36

symbiont benefits and host is harmed.

Question 37

Rhizobia

Answer 37

nitrogen-fixing bacteria forming root nodules in legumes.

Question 38

Nitrogen fixation

Answer 38

converting N₂ gas into usable ammonia for plants.

Question 39

Root nodule

Answer 39

plant structure housing nitrogen-fixing bacteria.

Question 40

Crown gall disease

Answer 40

plant tumors caused by DNA-inserting Agrobacterium.

Question 41

Ti plasmid

Answer 41

plasmid enabling Agrobacterium to insert DNA into plants.

Question 42

Microbiota

Answer 42

community of microbes living on and inside the human body.

Question 43

Competitive exclusion

Answer 43

Normal “good” bacteria in your body take up space and nutrients, leaving no room for pathogens to grow.

Question 44

Probiotics

Answer 44

beneficial microbes that support gut health.

Question 45

Fermentation (food)

Answer 45

bacterial metabolism used to make yogurt, cheese, pickles, soy products.