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1.1 The study of life Read Online
Viewed from space, Earth offers no clues about the diversity of life forms that reside there. The first forms of life on Earth are thought to have been microorganisms that existed for billions of years in the ocean before plants and animals appeared. The mammals, birds, and flowers so familiar to us are all relatively recent, originating 130 to 200 million years ago. Humans have inhabited this planet for only the last 2.5 million years, and only in the last 200,000 years have humans started looking like we do today.
Question: Strain differences are helpful in
Choices:
replica plating.
electrophoresis.
transformation.
transduction.
tracing the source of outbreaks of disease.
Question: Mycobacterium tuberculosis is one of the few species of bacteria that
Choices:
are encapsulated.
stain Gram-negative.
are acid fast.
stain Gram-positive.
Question: The basic taxonomic unit in the classification scheme of plants and animals is
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kingdom.
class.
order.
genus.
species.
Question: Intracellular Gram-negative diplococci found in a urethral sample from a male is indicative of
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coli.
Pseudomonas.
Streptococcus pneumoniae.
Neisseria gonorrhea.
Question: The point at which two organisms diverged from a common ancestor
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can be determined by comparing the nucleic acid sequences
depends on translational control.
depends on metabolism.
s determined on MacConkeys media.
Question: To study the phylogeny of eukaryotes
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16S rRNA is used.
34S rRNA is used.
80S rRNA is used.
18S rRNA is used.
Question: The more closely related two organisms are,
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the less they look alike.
the more similar the nucleic acid sequence.
the less similar the nucleic acid sequence.
the more they are phenotypically similar.
the more similar the nucleic acid sequence AND the more they are phenotypically similar.
Question: In 1970 Stanier proposed that classification be based on
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evolution.
Gram stain.
physiology.
DNA sequence.
Question: In the 1930s Kluyver and van Niel proposed a classification scheme based on
Choices:
Gram reactions.
biochemical relationships.
presumed evolutionary relationships.
DNA sequences.
Question: Media that changes color as a result of the biochemical activity of growing bacteria
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usually contain a pH indicator in the media.
usually contain blood.
usually require the addition of various reagents before the color is evident.
is due to a breakdown of a colorless reagent.
Question: The relatedness of organisms determined by counting common characteristics is called
Choices:
evolutionary taxonomy.
amino acid sequences.
DNA sequences.
numerical taxonomy.
suggests the organisms are very closely related at the species level AND means the GC content is 45%.