同化作用Assimilation
根據生物體在同化作用過程中能不能利用無機物製造有機物，新陳代謝可以分為自養型和異養型兩種。
自養型綠色植物直接從外界環境攝取無機物，通過光合作用，將無機物製造成複雜的有機物，並且儲存能量，來維持自身生命活動的進行，這樣的新陳代謝類型屬於自養型。少數種類的細菌，不能夠進行光合作用，而能夠利用體外環境中的某些無機物氧化時所釋放出的能量來製造有機物，並且依靠這些有機物氧化分解時所釋放出的能量來維持自身的生命活動，這種合成作用叫做化能合成作用。例如，硝化細菌能夠將土壤中的氨(NH3)轉化成亞硝酸(HNO2)和硝酸(HNO3)，並且利用這個氧化過程所釋放出的能量來合成有機物。總之，生物體在同化作用的過程中，能夠把從外界環境中攝取的無機物轉變成為自身的組成物質，並且儲存能量，這種新陳代謝類型叫做自養型。
According to whether an organism can use inorganic substances to produce organic substances during the assimilation process, metabolism can be classified into two types: autotrophic and heterotrophic.
In autotrophic metabolism, green plants directly absorb inorganic substances from the external environment and, through photosynthesis, convert these inorganic materials into complex organic compounds, storing energy to sustain their life activities.
This type of metabolism is classified as autotrophic.
A few types of bacteria, which cannot perform photosynthesis, instead use the energy released from the oxidation of certain inorganic substances in the external environment to synthesize organic compounds.
They then rely on the energy released from the oxidation and breakdown of these organic compounds to maintain their life functions.
This synthesis process is called chemosynthesis.
For example, nitrifying bacteria can convert ammonia (NH₃) in the soil into nitrite (HNO₂) and nitrate (HNO₃), using the energy released during this oxidation process to synthesize organic substances.
In summary, during assimilation, organisms can convert inorganic substances absorbed from the external environment into components of their own bodies and store energy.
This type of metabolism is referred to as autotrophic metabolism.