Brocks Chapter 1: True or False

Archaea and Bacteria are more similar than Eukarya

False

Small cells have more surface area relative to cell volume and thus have a higher surface-to-volume ratio

True

Archaea and Eukarya are more similar than Bacteria

True

Large cells have more surface area relative to cell volume and thus have a higher surface-to-volume ratio

False

S/V ratio of a cell controls many of its properties including its growth rate and shape

True

As cell size increases the s/v ratio increases

False

Appendages (e.g. stalks and hyphae) are used by some cells for motility

False

Appendages (e.g. stalks and hyphae) are used by some cells for attachment or to increase surface area

True

Some microbes get away with minimal genomic complement by obtaining nutrient from other organisms

True

There are square and hexagon shaped bacteria

True

Bacteria have eukaryotic cell structure

False

Bacteria have prokaryotic cell structure

True

All bacteria are unicellular

False

Most bacteria are unicellular

True

90% of cultivated bacteria belong to: Actinobacteria, Firmicutes, Proteobacteria, and Bacteriodetes

True

Bacteria only have four phyla: Actinobacteria, Firmicutes, Proteobacteria, and Bacteriodetes

False

Archaea have prokaryotic cell structure

True

Not all archaea have prokaryotic structure

False

All archaea are extremophiles

False

Archaea domain lacks any known disease causing species of plants or animals

True

Archaea are mostly disease causing prokaryotes

False

The first eukaryotes were unicellular

True

The first eukaryotes are plants

False

The largest unicellular organisms are eukaryotic

True

Viruses can replicate outside host cell

False

Viruses are obligate parasites that can only replicate within the cytoplasm of a host cell

True

Viruses do not carry out metabolic processes; instead they take over the metabolic systems of their infected cells

True

Viruses conserve genes

False

No genes are conserved among all viruses

True

During the first 2 billion years of Earth’s existence, its atmosphere was anoxic (O2 was absent), only nitrogen, carbon dioxide, and other few gases were present

True

The first phototrophs were aerobic bacteria, such as purple sulfur bacteria and green sulfur bacteria

False

The first phototrophs were anoxygenic (non oxygen producing), such as purple sulfur bacteria and green sulfur bacteria

True

80% of life’s history was exclusively prokaryotic

False

80% of life’s history was exclusively microbial

True

60 genes are found in all cells

True

Ruminants (like most animals) do not have enzymes to break down polysaccharide cellulose. Microorganisms in their rumen help digest and ferment cellulose.

True

Ruminants unlike other mammals have the enzymes to break down cellulose and doesn’t need the help of microorganisms to digest them

False

Microbial growth in food can only cause spoilage and food borne diseases

False

Products of microbial fermentation affect the flavor and taste of foods and can prevent spoilage as well as growth of deleterious organisms

True

Natural gas (Methane CH4) is a product of the anaerobic metabolism of methanogenic Archaea

True

Bioremediation accelerates industrial clean up by either adding special microorganisms to a polluted environment or by adding nutrients that stimulate indigenous microorganisms to degrade the pollutants

True

In bioremediation, chemicals are used to kill deleterious microorganisms from the environment. This clean up process also encourages growth of special microorganisms that degrade the pollutants.

False

Microbes can grow in almost any environment containing liquid water

True

Microbes thrive in dry environment

False

Magnification is the limiting factor in our ability to see small objects

False

Resolution governs out ability to see small objects

True

The total magnification of a compound microscope is the sum of the magnification of the condenser and the lenses

False

Higher magnification lower numerical aperture

False

Higher magnification typically have higher numerical aperture

True

Immersion oil increases the light gathering ability of a lens

True

Immersion oil increases magnification of a lens

False

In light microscopy, specimens are visualized because of the difference in contrast that exist between them and their environment

True

Bacterial cells typically lack contrast and are difficult to see well with the bright field microscope unless stained

True

Cell surfaces tend to be negatively charged

True

Cell surfaces tend to be positively charged

False

Staining hydrates the cell which can distort their features

False

Staining often kills cells and can distort their features

True

Dark field microscopy has better resolution than light microscopy

True

Light microscopy has better resolution than dark field microscopy

False

Dark field microscopy is particularly good in observing microbial motility, as bundles of flagella are resolvable with this technique

True

Phase contrast microscopy is particularly good in observing microbial motility, as bundles of flagella are resolvable with this technique

False

Dark field and phase contrast microscopy improve image contrast of unstained (and thus live) cells

True

In the electron microscope, electromagnets functions as lenses and the whole system operates inside a vacuum

True

In the electron microscope, cameras functions as lenses and the whole system operates inside a vacuum

False

Electron microscope allows for viewing of structures at the molecular level

True

Unlike photons, electrons are poor at penetrating. To view internal structures of a cell, thin sections are needed. (TEM)

True

Unlike photons, electrons are poor at penetrating. To view internal structures, staining us needed. (TEM)

False

Electron cryotomography is an imaging technique used to obtain 3D images

True

Electron cryotomography is a microscope used to obtain 3D images

False

For optimal 3D imaging of cells, a scanning electron microscope (SEM) is used but only the surface of an object is typically visualized

True

For optimal 3D imaging of cells, a transmission electron microscope (TEM) is used but only the surface of an object is typically visualized

False

Electron micrographs (taken by TEM or SEM) are black and white and color is often added through a computer. False color does not improve resolution.

True

Microorganisms cannot discriminate between optical isomers

False

Microorganisms can discriminate between optical isomers

True

Proponents of spontaneous generation criticized one os Pasteur’s experiments saying that “fresh air” is necessary for spontaneous generation

True

Proponents of spontaneous generation criticized one os Pasteur’s experiments saying that “fresh water” is necessary for spontaneous generation

False