Metabolism Flashcards
Holding electrons and hydrogens etc means that you’re _____.
Reduced
Losing electrons and hydrogens etc means that you’re _____.
Oxidized
Photosynthesis
CO2 + H2O –> CH2O
What are the ways that organisms obtain energy?
(1) Light, CO2 –> Photosynthetic autotrophs
(2) Inorganic molecules –> Chemosynthetic autotrophs
(4) Organic molecules –> Heterotrophs
Photo-autotrophs
Light is used to “pump up” low energy electrons from H2O or H2S and store energy into sugar
Chemo-autotrophs
Uses reduced inorganic compounds, requires less energy to remove than H-O bonds and store energy into sugar
What are the different methods of photosynthesis?
C3, C4, CAM
C3 Photosynthesis
- Light reaction (C fixation) and Calvin cycle in same chloroplast
- Trade-off between CO2 gain and water loss via stomata (CO2 gradient < water gradient)
- thrives where sunlight and temperatures are moderate, abundant CO2 and water
- RuBisCo, breaks RuBP (6C) into 3C sugar (3-Phosphoglycerate)
C4
- Two chloroplasts - Light reaction in mesophyll and Calvin cycle in bundle sheath cell
- Uses a 4C acid to separate fixation from synthesis
- Specialized bundle sheaths deep in tissue
CAM
- Photosynthetic steps are separated in time (day vs night)
- Light reaction occurs at night, stores 4C acid in vacuole, Calvin cycle use in daytime
Heterotrophs
Uses organic molecules created by other organisms as their source of carbon and energy
Omnivore
Varied diet
Insectivore
Eats insects
Piscivore
Eats fish
Herbivore
Eats plants
Carnivore
Eats animals/meat
Detritivore
Eats dead matter
Size selective predation
Selection of prey is usually dictated by size
For carnivores, prey is usually of similar/dissimilar nutritional value.
similar. Carnivores can typically vary their diet and eat what is available.
Challenges of carnivores
(1) Physical
(2) Aposematism (Mullerian/Batesian mimicry)
(3) Evasion
(4) Camouflage
Aposematism
Warning coloration/anti-predator adaptations
Mullerian mimicry
Poisonous animals look similar
Batesian mimicry
Non-poisonous animals look like poisonous species
What limits animal energy intake?
(1) Time spent searching for food
(2) Time spent handling/processing food
What are the types of animal functional responses?
(1) Type I–linear rise, abruptly levels off at the maximum feeding rate (spiders)
(2) Type II – linear rise, slowing at middle, gradual leveling off at the maximum feeding rate (most animals)
(2) Type III – S-shape, slow increase at low densities, rapid intake at middle, leveling off at high densities (snails)
Optimal foraging theory
If organisms have limited access to energy, natural selection will favor the most effective foragers.
Assuming energy is limited, an organism must trade-off or allocate resources to optimize some functions at the cost of others.
