Modes of Nutrition and Nutrition in Archaea

What are the two main modes of nutrition?

1. Autotrophs

2. Heterotrophs

What does an autotroph do?

synthesizes or produces its own organic molecules from simple inorganic compounds

What are the two types of autotrophs based on their energy source?

• photoautotrophs use light energy

• chemoautotrophs use energy from the oxidation of chemicals.

How do photosynthetic organisms obtain energy and produce organic molecules?

autotrophs = use light energy to convert carbon dioxide from the air into organic molecules like carbohydrates

What are some examples of photosynthetic organisms?

plants, algae, some bacteria (cyanobacteria)

What does a heterotroph do?

gain organic molecules from tissues of other organisms

What is holozoic nutrition?

a type of heterotrophic nutrition where organisms gain organic molecules by ingesting, digesting, absorbing, and assimilating molecules

How do single-celled organisms like Amoeba perform holozoic nutrition?

They engulf food particles through endocytosis and digest them in specialized vesicles, despite lacking a multi-organ digestive system.

What are saprotrophs?

heterotrophs that ingest the tissues of dead organisms and waste material

How do saprotrophs digest dead organisms/waste materials?

by secreting enzymes onto their food and digesting it externally before absorbing the products of this digestion

Example of saprotrophs

fungi and bacteria (generally described as decomposers)

What is a mixotroph?

an organism that can use a mix of different sources of energy/carbon

What are mixotrophs in marine plankton?

Unicellular eukaryotic protists

What are the two types of mixotrophs?

• Facultative mixotrophs

• Obligate mixotrophs

What are facultative mixotrophs?

can be entirely autotrophic, heterotrophic or use both modes

What are obligate mixotrophs?

these must use both modes of nutrition

What are the three categories living things can be categorized into?

• Archaea

• Bacteria

• Eukaryotes

Where are archaea often found?

in extreme conditions such as hot springs, salt lakes, or volcanic craters.

What are the three archeaic domains?

• Phototrophic

• Chemotrophic

• Heterotrophic

What do phototrophic archaea do?

using light as an energy source to produce sugars

What do chemotrophic archaea do?

use inorganic chemicals such as iron by oxidizing to produce sugars.

What do heterotrophic archaea do?

oxidizing organic compounds obtained from other organisms and digesting them.