Microbio Exam 1 quizes

Why was the recognition of Archaea as a separate domain significant?

They were previously grouped with Bacteria but have distinct evolutionary lineages

Microbes are responsible for a smaller fraction of total photosynthesis than plants

False

Which of the following is NOT a typical feature of a eukaryotic cell

A peptidoglycan cell wall surrounds each cell

The earliest evidence of life on Earth consists of fossil microbial communities Designated

stromatolites

Microbes are either single-celled, colonial or filamentous organisms

True

Prokaryotic microbes had a central role in the evolution of Earth and life on it

True

Match each branch of Microbiology with an activity related to it

Food Microbiology – Preventing food spoilage, Industrial Microbiology – Biotechnological production of pharmaceuticals, Environmental Microbiology – Cleaning up oil spills, Medical Microbiology – Infectious disease control

Most bacteria cause disease to humans or animals

False

Microbes have an essential role in the decomposition of organic matter and the recycling of carbon

True

All microorganisms are microscopic

False

What kind of microscopy shows images at the highest resolution?

Electron microscopy

We can visualize viruses using a light microscope.

False

Connect each medium with the best definition

Synthetic medium – Is chemically defined, Rich medium – Has plenty of nutrients for faster growth, Selective medium – Inhibits growth of most microbes, Differential medium – Allows visual discrimination between organisms

Phase contrast microscopy is used to

Increase sample contrast for better visibility

Isolation involves the physical separation of a microbe of interest from others present in a sample

True

Isolated colonies on a plate of solid medium are generally assumed to be the progeny of a single cell

True

Fill in the blank. Any medium containing an antibiotic is a ……………………………. medium

selective

Bacteria causing disease to humans grow best at

Approximately 37ºC

In fluorescence microscopy a laser beam focused on the cells is reflected towards the microscope lens system

False

Staining is a method for increasing contrast of living specimens

False

Which of the following statements best describes how fimbriae and capsules differ from each other

Fimbriae are filamentous structures whereas capsules are not

Which of the following statements about a gram-negative cell wall is true?

It contains lipopolysaccharide (LPS)

Fill in the blank. A chains of spherical bacterial cells cell is named a

streptococcus

Fill in the blank. When essential nutrients are depleted, some strains of bacteria form

endospores

Epulopiscium fishelsoni is 0.5 mm in diameter. It contains no nucleus and has peptidoglycan. Due to the size of this cell, it should be classified as a eukaryote.

False

Which of the following is not a structure of prokaryotic cells?

chloroplast

The term describing bacteria with flagella distributed over the entire surface of the cell is

peritrichous

Gram-negative bacteria have an outer membrane containing lipopolysaccharide (LPS).

True

Bacteria do not have chloroplasts and therefore cannot perform photosynthesis.

true

A student finds a prokaryote that thrives at 90°C, produces methane, and has no peptidoglycan. To which domain does this organism most likely belong?

Archaea

All eukaryotes contain

a membrane-enclosed nucleus

Which statement is TRUE of endoplasmic reticula under most circumstances?

The rough endoplasmic reticulum is involved in protein synthesis, whereas the smooth endoplasmic reticulum is involved in lipid synthesis

Mitochondria and chloroplasts have their own DNA but use the ribosomes of the host cell.

True

The mitochondrion contains membrane-bound proteins involved in cell respiration and the harvesting of energy

True

Where within a eukaryotic cell is ribosomal RNA (rRNA) synthesized?

nucleolus

The Golgi apparatus functions to

both modify and sort proteins into those targeted for secretion and those targeted to different organelles

Yeasts are ____fungi , and molds are _____ fungi.

unicellular, filamentous

Which of the following choices is the highest level of taxonomic hierarchy?

Domain

A new soil microorganism has been described. On some growth media, it forms colonies of unicellular organisms; but under certain conditions it forms long, multicellular filaments and spores. The cells have nuclei, and their cell walls are composed of chitin. To which of the following groups does this new organism belong?

fungi

Which of the following choices is NOT a feature of algae

They lack mitochondria

After attachment to a host cell, what is the next step in the multiplication of animal viruses?

penetration

Retroviruses

do all of the above: synthesize DNA from RNA template, integrate their genetic material in the host's chromosome during their life cycle, include the virus that causes AIDS

Viruses can be grown only on living hosts.

True

Viruses infecting…………………………..are known as phage.

bacteria

Penetration requires that the entire virion be translocated inside a host cell.

False

Viral replication is

Dependent on the its host's functions

The nucleic acid of a virus is

Either DNA or RNA

Viral replication occurs

intracellularly

Viruses have both an intracellular and an extracellular form.

True

Which method cannot be used to culture viruses in a laboratory?

nutrient agar culture media