Midterm 2-Feeding and trophy Flashcards
Trophic strategies
What 6 things does all cellular life need to take from the environment?
- Water 2. Energy 3. Sources of Carbon 4. Reducing power (e donor) 5. Electron acceptor 6. Sources of other elements (n/p/s/fe)
Trophic strategies
Define 2 Sources of energy
Chemotrophs: use chemical bonds in molecules Phototrophs: use light/photons
ex. animals/plants
Trophic strategies
Define 2 sources of reducing power?
Electron donor/oxidations
Organotrophs: use organic molecules Lithotrophs: use inorganic molecules
ex. Glucose&lipids/ water in photosynthesis
Trophic strategies
Define 2 sources of electron acceptors
Not referred to as food
Aerobes: use oxygen Anerobes: use anything else
ex. humans/ Co2 in photosynthesis
Trophic strategies
Define 2 sources of Carbon
Heterotrophs: use organic molecules Autotrophs: Use inorganic molecules
ex. Sugars/photosynthesis uses CO2 (inorganic C)
Trophic strategies
Define sources of other elements
*Nitrogen/Phosphorus/Sulfur/Iron
Variable- can get N from proteins in organic molecules (us) or from inorganic in soil (ammonia/nitrate in plants)
Trophic strategies
Define photosynthesis
oxygenic
The process of fixing Co2 into organic compounds (autotrophy) by using energy obtained from photons (phototrophy)
Trophic strategies
What is anyoxygenic photosynthesis?
An unrelated process developed by some bacteria that does not produce oxygen
E- donor is not water
Trophic strategies
What 2 classes do all eukaryotes fall into?
Chemoorganoheterotrophs or photolithoautotrophs
heterotrophs (organic)/phototrophs (inorganic)
Can be aerobic or anaerobic
Feeding in Protists- Heterotrophs
What groups can do osmotrophy?
Bacteria/Archae are great at this, the only eukaryote is FUNGI
fungi use Hyphae for surface area
Feeding in Protists- Heterotrophs
What is osmotrophy?
Digestive enzymes are excreted outside cell –> broken down into smaller molecules that are then actively transported in
Feeding in Protists- Heterotrophs
Name 2 reasons why Eukaryotes are not great at osmotrophy
- Less metabolically diverse: fewer and less effective digestive enzymes 2. ** Surface to volume ratio**: Eukaryotes tend to be bigger than bacteria
Feeding in Protists- Heterotrophs
What are Oomycetes
Stramenopiles
POTATO BLIGHT
Efficient parasites, have hyphae- Unrelated (but not totally independant) from Fungi
convergent evolution- genes from horizontal gene transfer from FUNGI
Feeding in Protists- Heterotrophs
What is phagotrophy?
First cells to eat another- evolution game changer
The entire particle is engulfed by membrane through vacuoles
Feeding in Protists- Heterotrophs
What are the 3 types of phagotrophy?
Define
- Raptorial: Search and move towards prey 2. Diffusion: prey bumps/falls into it 3. Filter: filters prey from surrounding water (may generate current)
Feeding in Protists- Heterotrophs
How do protist predators find prey?
Raptorial feeding
NOT SIGHT, maybe hearing YES smell /CHEMICALS
Feeding in Protists- Heterotrophs
Define Extrusomes
Raptorial feeding
Organelles that are just below the plasma membrane, function to do exocytosis and release content
Feeding in Protists- Heterotrophs
What does Acantharian feeding use?
Radiolarian
Diffusion feeding- Prey touches axopods which triggers kinetocysts to release content (sticky glue) then retracts to centre of cell where it will feed
Feeding in Protists- Heterotrophs
How do ciliates feed?
2 ways
Raptorial feeding- Have toxicysts to inject poison to stop from swimming, then injests it ALSO filter feeding
Apex predators of protists
Feeding in Protists- Heterotrophs
How do lobose ameobas feed?
Raptorial: overwhelm with size and trap
Feeding in Protists- Heterotrophs
How do Choanoflagellates feed?
Opisthokonta
Filter feeding: Use flagella to generate water current and filter to find prey of right size, feeds at “collar”
Use “Stock” or “Colonies” to anchor to something
Feeding in Protists- Heterotrophs
How do Excavata feed?
Filter: Have a feeding grove surrounded by flagella that beat to generate water current
Feeding in Protists- Heterotrophs
What is the main difference between filter and raptorial feeding?
Filter feeding can only be eat things SMALLER than them
Feeding in Protists- Heterotrophs
What is a cytosome?
A specialized part of the cell that does phagocytosis with no rigid structures below the surface
Ameobas are an exception
Feeding in Protists- Heterotrophs
How do dinoflagalletes feed: palium feeding?
(half photosynthetic half heterotrophic)
Alveolata
Palium feeding: A large veil extension of the cytoplasm that envelops and digests LARGE prey outside of the cell then transports nutrients in
Extensions are classified as psudopodia
Feeding in Protists- Heterotrophs
How do dinoflagalletes feed: Myzocytosis
Half photosynthetic half heterotrophic
Alveolata
Pierce plasma membrane of prey and “suck in” nutrients
Feeding in Protists- Heterotrophs
How does Vampyrellids feed?
Rhizaria- weird example
Fillose ameoba that pierce holes through thick cellulose algae walls and ingest the whole cell
Myzocytosis
Feeding in Protists- Heterotrophs
How does pseudomicrothorax feed?
CIliate- weird example
Eats cyanobacteria (forms long filamentous colonies) cytosome is reinforced by Mts for specialized feeding of long prey
Feeding in Protists- Heterotrophs
Steps of digestion
5
- Food vacuole detaches from cytosome to become Digesive vacuole (DV) 2. Acidosomes fuse with Dv and lower pH 3. Lysosomes fuse with DV and release lytic enzymes 4. Digested contents + enzymes pinch off in vesicles 5. Undigested content/waste is defecated when DV fuses with Cytoproct
Feeding in Protists- Heterotrophs
What is Cyclosis
The digestive vacuole moves slowly in a pre-defined path within cytoplasm
Feeding in Protists- Heterotrophs
Prey fighting back: shapeshifting
Euplotes- Ciliate
Senses predators and flattens to become harder to eat
Euplotes- Ciliate
Feeding in Protists- Heterotrophs
Prey fighting back: defensive extrusomes
Paramecium
Uses trichocysts to stun predators
Feeding in Protists- Heterotrophs
Prey fighting back: Defensive symbionts
Euplotidium- ciliate
band of spherical balls (symbiotic bacteria) OUTSIDE cell that stun prey
Not extrusomes- outside cell
Feeding in Protists- Heterotrophs
Parasites: intra vs extra cellular
Apicomplexans
Intra: surrounded by food, can do osmotrophy (toxoplasma/plasmodium) Extra: mostly phagotrophic (gregarians)
Feeding in Protists- Heterotrophs
How do Microsporidians feed?
Opisthokonts
Energy parasites- steal ATP from host
Microsporidian - Opisthokonts
Feeding in Protists- Mixotrophs
What is a Mixotroph?
An organism that can do both heterotroph and autotroph strategies
Feeding in Protists- Mixotrophs
3 Mixotroph strategies
- Algae- photosynthetic dinoflagalletes or unicellular green algae 2. Heterotrophs with algal symbionts 3. Kleptoplastidy
Feeding in Protists- Mixotrophs
What is a Haptonema?
Haptophytes
A specialized feeding structure in Haptophytes that moves food to opposite side of cell
Feeding in Protists- Mixotrophs
Micromonas feeding strategy
Green algae
Mixotroph- does photosynthesis and eats bacteria (phagocytosis)
Feeding in Protists- Mixotrophs
Why does an Algal symbiont not count as an organelle?
The Algae are not dependant on the host, can still live on its own
NO PROTEIN TARGETING
Feeding in Protists- Mixotrophs
Why are kleptoplastids often lost quickly?
The host is missing essential genetic information to keep plastid alive
Feeding in Protists- Mixotrophs
List groups that do Kleptoplastidy?
Foraminiferan, Euglenid, Dinoflagallete and SOME animals!
Feeding in Protists- Mixotrophs
Who does Mesodinium steal plastids from?
Heterotrophic ciliate
Cryptophyte (secondary red algae, 4 membranes)
Feeding in Protists- Mixotrophs
Why is Mesodinium rubrum so good at keeping plastids alive?
Not only steals the plastid, also steals the nucleus from DIFFERENT cryptophytes
Feeding in Protists- Mixotrophs
How does Dinophysis get its plastid (cryptophyte)
Dinoflagallete- heterotrophic
By eating mesodinium and keeping ONLY plastid- no nucleus
Feeding in Protists- Mixotrophs
How can Dinophysis keep its plastid alive if it does not steal nucleus as well?
Dinoflagallete- heterotrophic
Ancestor of dinophysis used to have plastid- still has plastid derived genes (red algae 3 mem)
Digests everything but 3 membraned plastid- same as ancestors
