Assessment 4: CH17-20

What type of metabolism do eukaryotes conduct?

• heterotrophy only

• oxygenic photosynthesis, heterotrophy, or both

• oxygenic photosynthesis only

oxygenic photosynthesis, heterotrophy, or both

“Incompletely described,” emerging organisms are on their way to be established as new species. In the meantime, they can be designated as all of the following EXCEPT a(n)

• candidate species.

• type species.

• unclassified organism.

type species

The following is correct about a probabilistic indicator for bacterial identification, EXCEPT that

• it is based on yes/no choices that successively narrow down the identification of a taxon.

• it requires a predefined database of known bacteria.

• numerous strains of each species in well-studied habitats must be isolated in pure culture and tested for a defined number of traits.

it is based on yes/no choices that successively narrow down the identification of a taxon.

Horizontal gene transfer can occur by all of the following EXCEPT

• plasmid acquisition.

• transformation processes.

• parent to offspring.

parent to offspring.

An ancient ________ is assumed to be in the same lineage as mitochondria.

• Rickettsia

• Mycoplasma

• Rhizobium

Rickettsia

A clade could best be described as a

• hypothesis that early evolution happened faster than later evolution.

• group of related organisms producing a monophyletic group.

• random but neutral DNA mutation.

hypothesis that early evolution happened faster than later evolution.

Organisms in the ________ clade have lost their mitochondria through the process of reductive (degenerative) evolution.

• Heterokonta

• Alveolata

• Metamonada

Metamonada

Molecular clocks use genes that

• are found primarily on plasmid DNA.

• are involved in transcription and translation.

• code for TCA cycle enzymes.

are involved in transcription and translation.

Which of the following is NOT used as a criterion to define a prokaryotic species?

• Members of different species cannot interbreed.

• Phylogenetic relatedness is not a criterion.

• The average nucleotide identity (ANI) of orthologs ≥ 95%.

Members of different species cannot interbreed.

Members of order ________ in the human gut may couple with methanogens to provide the hydrogen gas for methanogenesis.

• Desulfurococcales

• Thermococcales

• Clostridiales

Desulfurococcales

A trait that differentiates all Firmicutes from Actinobacteria is

• GC content.

• pathogenicity.

• Gram stain character.

GC content

Based on small subunit rRNA phylogeny studies, the current view is that there are ________ domains of life.

five

three

two

Three

One of the smallest eukaryotes recently discovered, the green alga Ostreococcus tauri, measures less than ________ across and its genome (8 Mb) is ________ the size of that of Escherichia coli.

• 500 nm; half

• 2 µm; barely twice

• 1 µm; three times

2 µm; barely twice

The protozoa were considered to be microscopic animals because

• they are bigger than bacteria.

• of their ability to move.

• of their capacity to cause disease.

of their ability to move.

A bacterial phylum is a group of organisms that share a common ancestor that diverged early from other bacteria, based on

• small-subunit (16S) rRNA sequences.

• having 70S or 80S ribosomes.

• the presence of certain plasmids.

small-subunit (16S) rRNA sequences.

Which of the following is NOT correct about microorganisms in the phylum Thermotogae?

• Archaeal genes have been transferred horizontally to them.

• They are bacterial thermophiles.

• They are aerobic heterotrophs.

They are aerobic heterotrophs.

The term “protist” describes single-cell and colonial eukaryotic organisms other than _____________

• paramecia.

• fungi.

• diatoms.

Fungi

Which of the following is the organizing body that sets the rules for naming a new prokaryotic species or taxa?

• the International Journal of Systematic and Evolutionary Microbiology

• Bergey’s Manual of Determinative Bacteriology

• the International Committee on Systematics of Prokaryotes

the International Journal of Systematic and Evolutionary Microbiology

Which of the following is unique to archaea?

• pseudopeptidoglycan

• supercoiled DNA

• S-layers

pseudopeptidoglycan

The following are examples of challenges for classification of eukaryotes, EXCEPT

• genome size and complexity has delayed completion of genomic sequences.

• eukaryotes have experienced multiple endosymbiotic events.

• eukaryotic chromosomes are located inside the nucleus.

eukaryotic chromosomes are located inside the nucleus.

Which group has the widest range of form but the least diversity in terms of metabolism?

• eukaryotes

• archaea

• viruses

eukaryotes

A dichotomous key is a

• series of yes/no choices that successively narrows down a possible taxonomic category

• detailed description of a taxon with diagnostic purposes.

• battery of biochemical tests used to identify organisms in a particular taxon.

series of yes/no choices that successively narrows down a possible taxonomic category

All of the following are characteristics of eukaryotic organisms EXCEPT

• all types of eukaryotic cells are surrounded by a cell wall.

• their cells possess a nucleus.

• they are highly compartmentalized and have an endomembrane system.

all types of eukaryotic cells are surrounded by a cell wall.

Bacteria are widely diverse in their cell structure, metabolism, and ecological adaptations, but share some major common traits. Which of the following statements is NOT true?

• Bacterial gene expression mechanisms differ from those of the eukaryotes, which underlies the selective activity of many antibiotics.

• They share common features in central apparatus for gene expression and translation.

• Mycoplasmas contain abnormal peptidoglycans and are thus not susceptible to antibiotics.

Mycoplasmas contain abnormal peptidoglycans and are thus not susceptible to antibiotics.

________-branched chains increase membrane stability.

• Diether

• Ester

• Isoprenoid

Isoprenoid

Which branch of taxonomy deals with the sorting of life-forms into bins (categories) based on genetic relatedness and traits of the organisms?

• biogeography

• classification

• identification

classification

In the domains of life, archaea and eukarya differ from each other in that archaea ________ and eukarya ________.

• do not contain membrane-bound organelles; do

• contain membrane-bound organelles; do not

• do not undergo methanogenesis; do

do not contain membrane-bound organelles; do

Spikes in ________ content often indicate that a horizontal gene transfer has occurred in the genome.

AT

AC

GC

GC

The loss of genes encoding for unselected traits is known as

• natural selection.

• random mutation.

• reductive evolution.

reductive evolution

Taxonomy can be defined as the

• recognition of the class of a given microbe isolated in pure culture.

• identification of a species in a sample or collection.

• classifying of life forms into different categories with shared traits.

classifying of life forms into different categories with shared traits.

The term “pan-genome” can best be defined as

• the sum total of all expected genes in all possible isolates of a given species.

• genomic islands found in pathogenic organisms.

• the world DNA genomic databank.

the sum total of all expected genes in all possible isolates of a given species.

What trait do all cells on Earth NOT have in common?

• double-stranded DNA

• cell wall of varying composition

• universal gene code, common ancestral rRNAs, and elongation factors

cell wall of varying composition

Clades of microbes that are recently defined or characterized are referred to as

• hyperthermophiles.

• archaea.

• emerging.

emerging

The term “________” indicates that the members of a clade share a common ancestor, one not shared by any group outside the clade.

• monoploid

• polyphyletic group

• monophyletic group

monophyletic group

A molecular clock is best defined as

• genes that under selective pressure show a higher rate in mutation frequencies.

• organisms in favorable environments that have greater offspring potential.

• the information contained in DNA or protein sequences that shows changes over time.

the information contained in DNA or protein sequences that shows changes over time.