Bacterial Diversity

Lithotroph

inorganic energy source

Sulfur Reducer

sulfate

Sulfur Oxidizer

H2S

Iron Oxidizer

Fe+2

Autotroph

CO2

Heterotroph

Glucose

Denitrification

N2

Phototroph

Light energy

Which is most primitive organism?

Which is the most evolved organism?

What is the closest relative to EM 17?

Aquifex pyrophilus

Which of the outgroup organisms has the closest evolutionary relationship to the monophyletic bacterial group?

Escherichia coli

Which of the following domains of life include organisms commonly referred to as “prokaryotes”?

Bacteria and Archaea

Which microbial group is responsible for the production of the majority of Earth’s atmospheric oxygen?

Cyanobacteria

Which of the following processes is the most commonly used by chemolithoautotrophic bacteria to fix carbon?

Calvin-Benson-Bassham Cycle

Methanogens are Archaea that produce methane gas as a metabolic byproduct. In what type of environment are they commonly found?

Anaerobic

The 12 essential biomass precursors include all of the following except:

glucose

What is the significance of the “Great Oxygenation Event” in Earth’s history?

it resulted in the accumulation of oxygen in the atmosphere

What is the key difference between eukaryotic and bacteria or archaea cells?

Eukaryotic cells have a nucleus, while bacteria and archaea cells do not

Archaea are often found in extreme environments such as hot springs and salt flats due to their:

unique cell membrane composition

The tree of life is a visual representation of:

the history of life on Earth

Which of the following is a characteristic feature of bacteria?

cell wall made of peptidoglycan

Which group of microorganisms is responsible for the majority of nitrogen fixation on Earth?

Bacteria

The domain Archaea is more closely related to which domain of life?

Eukarya

What is the primary purpose of 16S microbial profiling?

identifying bacterial species

Which component of the bacterial cell is targeted for analysis in 16S microbial profiling?

Ribosomal RNA

What is the length of the 16S rRNA gene typically used in microbial profiling studies?

roughly 1000 base pairs

What is the primary difference between aerobic and anaerobic respiration?

the terminal electron acceptor

What is the significance of the hypervariable regions in 16s rRNA gene sequencing?

they are used for microbe identification

The endosymbiotic theory suggests that mitochondria in eukaryotic cells are derived from:

Bacteria

Which hypothesis proposes that eukaryotic cells originated through the relationship between a hydrogen oxidizer and a hydrogen reducer?

Hydrogen hypothesis

What is the main piece of evidence supporting the endosymbiotic theory for the origin of mitochondria and chloroplasts?

Similarities between the genetic material of the organelles and bacteria

Which of the following is a key event in eukaryogenesis?

Acquisition of nucleus

The reduction of nitrate to nitrogen gas during denitrification occurs under what environmental condition?

Anaearobic

Which enzyme complex catalyzes the reduction of atmospheric N2, to NH in diazotrophs?

Nitrogenase

In stable isotope probing experiments, how do researchers differentiate between labeled and unlabeled microbial cells?

By analyzing the stable isotope composition of biomolecules

The heterodisulfide reductase reaction in methanogens involves:

Recycling of coenzyme M and coenzyme B from their heterodisulfide

In FISH, what is used as probes to hybridize with target microbial nucleic acid sequences?

Short DNA or RNA molecules labeled with fluorescent dyesrev

Reverse electron transport is necessary in purple sulfur and nonsulfur bacteria primarily because:

Their reaction centers generate electrons at too high a potential to reduce NAD(P)+ directly

Why are methanotrophs considered obligate aerobes?

Oxygen is required to oxidize methane