Question 1

Two kinds of organisms living together in ways beneficial to both is called:

Accepted Answer

Mutualism is a type of symbiotic relationship where both organisms involved benefit from the interaction, fitting the description given.

Question 2

A parasite is also a(n):

Accepted Answer

Parasites are considered heterotrophs because they obtain their nutrients by consuming other organisms, rather than producing their own food or fixing nitrogen.

Question 3

The secretory systems of Type III and Type IV pathogenic bacteria differ in their mode of attacking cells in which of the following ways?

Accepted Answer

Type III secretion systems are often described as using a needle-like apparatus to inject toxins directly into host cells, functioning somewhat like a syringe. Type IV secretion systems, on the other hand, are known for their ability to transfer DNA and proteins into host cells, often using structures that resemble pili, which act as conduits for this transfer.

Question 4

Some bacteria exhibit a primitive form of behavior in that they can sense the properties of their environments and use that ability to make adaptive responses. Which of the following are NOT capabilities of any known bacterium?

Accepted Answer

All the capabilities listed (A through D) are indeed exhibited by some bacteria. For example, magnetotactic bacteria can orient themselves along the Earth's magnetic field, bacteria can aggregate in response to chemical signals (quorum sensing), some can move to find nutrients or light by moving upward in the water column, and bacterial conjugation involves the transfer of DNA between individual bacteria.

Question 5

The Danish physician Hans Christian Gram

Accepted Answer

Hans Christian Gram developed the Gram-stain technique, a method for distinguishing between different types of bacteria, which is crucial in the identification of bacteria in medical and scientific settings. The other options are inaccurately attributed to him.

Question 6

Many new, previously unsuspected species have been discovered through application of the molecular technique of DNA sequencing.

Accepted Answer

DNA sequencing allows scientists to identify genetic differences and similarities at the molecular level, leading to the discovery of new species that may not have been distinguishable based on physical characteristics alone.

Question 7

Heterocysts are specialized cells in plant roots that contain nitrogen-fixing bacteria.

Accepted Answer

The answer of Heterocysts are specialized cells in plant roots...

Question 8

Various anaerobic Archaea that convert carbon dioxide and other carbon-bearing compounds into methane are called methanotrophs.

Accepted Answer

Methanotrophs are bacteria that consume methane, whereas the anaerobic Archaea that convert carbon dioxide and other carbon-bearing compounds into methane are called methanogens.

Question 9

Type III and Type IV systems are potentially applicable to treatment of human disease by using them to deliver DNA to target cells in human gene therapy.

Accepted Answer

Type III and Type IV secretion systems, found in various bacteria, have mechanisms that can be harnessed for the delivery of DNA or therapeutic molecules into human cells, offering potential strategies for gene therapy and treatment of diseases.

Question 10

Archaea are prokaryotes and Bacteria are eukaryotes.

Accepted Answer

Both Archaea and Bacteria are prokaryotes, meaning they do not have a nucleus or membrane-bound organelles. Eukaryotes, on the other hand, do have these features.

Question 11

A pathogen is a parasitic microbe.

Accepted Answer

A pathogen is a microorganism that causes disease, and many pathogens are parasitic, meaning they live on or in a host organism and cause harm.

Question 12

Feeding antibiotics to livestock promotes human health.

Accepted Answer

Feeding antibiotics to livestock can lead to antibiotic resistance, which poses a significant threat to human health by reducing the effectiveness of antibiotics for treating infections in humans.

Quiz 27: Bacteria and Archaea