Environmental Microbiology & Microbial Branches

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10 Questions

What is the term used to describe a group of microorganisms belonging to the same species or sharing a metabolic function?


Define the term 'Consortium' in the context of microbial ecology.

A group of microbial populations sharing the same habitat and connected by metabolic pathways.

How can an ecosystem be defined in the context of microbial ecology?

All microorganisms and their interactions with macroorganisms and the physical environment.

Explain the concept of a rank-abundance curve in a microbial community.

It represents different species in a community ordered by abundance, from most abundant to least abundant.

What happens to cells during the STATIONARY phase in microbial growth?

The number of cells neither increases nor decreases, some cells are active, some are dying, and some are being generated.

When do cells begin to die in a microbial population?

When the nutrient in the system is exhausted.

How do microorganisms interact in a consortium?

By sharing the same habitat and being connected through metabolic pathways.

Differentiate between an organism and a population in microbial ecology.

An organism is usually a single cell, while a population is a group of microorganisms belonging to the same species or sharing a metabolic function.

What is the primary difference between a prokaryote and a eukaryote?

Prokaryotes lack a nucleus and membrane-bound organelles, while eukaryotes have a nucleus and organelles.

How do microorganisms adapt to different sizes in the marine environment?

They can exhibit size variation to optimize their survival and function in diverse marine habitats.

Study Notes

Environmental Microbiology

  • Environmental microbiology is the study of microbial diversity and processes mediated by microorganisms.
  • There are three branches of microbiology: environmental microbiology, microbial ecology, and applied microbiology.

Microbial Diversity

  • Microorganisms were the only inhabitants of Earth for most of its history.
  • They belong to three domains: bacteria, archaea, and eukarya.

Prokaryotes vs Eukaryotes

  • Prokaryotes are smaller in size and are included in the picoplankton, while viruses are categorized as femtoplankton.
  • Marine microorganisms are small due to the lack of nutrients in seawater and diffusion problems.
  • The ratio of surface area to volume changes as the size of the organism increases.

Characteristics of Archaea

  • Archaea are similar in size to bacteria (1-10 μm), with marine prokaryotes at the lower limit of this range or even smaller (< 0.3-0.6 μm).

Biofilm Formation

  • Biofilms are formed by prokaryotes to obtain and retain nutrients, and to protect themselves from adverse environmental conditions, grazers, and toxic compounds.
  • Biofilms have various functions, including:
    • Retaining nutrients and humidity
    • Protecting from desiccation
    • Enhancing extracellular digestion of complex molecules
    • Facilitating close association of prokaryotes from different species to form consortia
    • Promoting horizontal gene transfer (HGT) in aerobic environments
    • Protecting anaerobes from oxygen by a layer of aerobes
    • Resisting penetration of antibiotics, biocides, and other toxic compounds
  • 40-80% of prokaryotes on Earth live in biofilms, which is the preferred mode of growth everywhere except in the open ocean, where planktonic growth is the norm.

Explore the field of environmental microbiology, microbial diversity, microbial ecology, and applied microbiology. Learn about the processes mediated by microorganisms and the interactions among different microorganisms.

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