Symbiosis

Question 1

Lichens

Answer 1

• Mutualism
• Fungus, Alga, Cyanobacteria
• Fungus: anchor, protection, minerals
• Alga: sugars and biomass
• Cyanobacteria: sugar and nitrogen fixing

Question 2

Choral

Answer 2

• Mutualism
• Coral + dinoflagellate
• dinoflagellate: photosynthesize and provide sugar
• coral: provide shelter

Question 3

3 Bacterial endosymbionts of tsetse fly

Answer 3

1. wolbachia: increase germ cell production and HGT
2. wigglesworthia: provide vitamins
3. soldalis: might increase suseptibility to trypanosome infection

Question 4

Termites

Answer 4

• mutualism
• termites: provide shelter
• protists in termite gut that take in cellulose
• bacterium in protist gut ferment cellulose into acetic acid which termites can use to eat more wood

Question 5

Hydrothermal vents with tube worm

Answer 5

• mutualism
• tubeworm trophosome and endosymbiont
• endosymbiont takes sulfer from environment to produce sugar for tubeworm
• tubeworm provides shelter

Question 6

Aphid

Answer 6

• mutualism
• aphid and buchnera
• buchnera: digests amino acids

Question 7

Mosquitos

Answer 7

• mutualism
• wolbachia and mosquito
• wolbachia: protects mosquito from viruses

Question 8

Ectomycorrhyzae

Answer 8

• fungi on plant root surface
• fungi: absorb nutrients for plant
• plant: provides sugar to fungi
• mutualism
• lots of plants and fungi can do this

Question 9

Endomycorrhyzae

Answer 9

• fungi is inside plant
• plant and fungi specificity

Question 10

Endophytes

Answer 10

• grow inside plant tissue
• found on all plants

Question 11

Nitrogen fixation methods (human versus microbe)

Answer 11

• haber rxn (humans): requires metal catalyst and high temp and pressure
• microbes: requires nitrogenase enzyme and occurs at normal temp and atmosphere

Question 12

What structures on legumes hold nitrogen-fixing rhizobia

Answer 12

• nodules
• nitrogen-fixing helps plants grow better
• there is plant to bacteria specificity = only rhizobia bacteria and only legumes

Question 13

How do rhizobia attach and form nodules

Answer 13

1. Recognition
2. Attachment
3. Invasion which causes root hair curling and bacterial release in plant cell
4. Differentiation: plant cells differentiate

Question 14

What is the 2-way communication model between legums and rhizobium?

Answer 14

• plant secretes flavonoid which induces rhizobium differentiation
• rhizobium secretes nod factor (lipopolysaccharide) which induces plant differentiation
• both flavonoid and nod factor are species specific

Question 15

What are other plant pathogens

Answer 15

1. Viral = tulips
2. Bacterial = rose stem
3. Fungal = white oak leaf
4. Phytopthora = Potato (irish potato famine