BIOL1006 Lecture Notes - Lecture 19: Chemotroph, Heterotroph, Extremophile
24 Jul 2018
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Document Summary
Why cells are small : constrains on cellular energy production. Fungi obtain energy by absorption (heterotrophs) (live off decaying stuff) Plants obtain energy from the sunlight (autotrophs) Chemoheterotrophs metabolise organic substances for both carbon and energy. Chemoautotrophs reduce dioxide to organic carbon using water or hydrogen gas as a reductant (also called lithoautotrophs living on rocks") Photoheterotrophs rely on sunlight for energy but use organic compounds as ready- made metabolic building blocks. Photoautotrophs capture and store sunlight in the chemical bonds of atp and carbs. Heterotrophs obtain their energy from ingesting autotrophs and heterotrophs. Heterotrophs recycle energy present in their food ( rst law of thermodynamics : energy can only be transferred or transformed not created) Ultimately all energy is based on captured sunlight. A process will only happen spontaneously (without added energy) if it increases the temperature of the universe as a whole. A measure of the amount of usable energy (energy that can do work) in that system.
