Mastering Biology

What is the major difference between the domains, Bacteria and Archaea?
Peptidoglycan in the cell wall of bacteria but not the archaea
The routine laboratory procedure used to classify the bacterial world into two majors groups is called the _____
Gram stain
Genera that contains spherical-shaped bacteria
What is the purpose of a prokaryotic flagellum?
They provide a mechanism of motility for the cell
What initiates sporulation in bacteria?
Environmental conditions, such as desiccation, that make the environment inhospitable
The polymerase chain reaction requires a heat-resistant enzyme. What is the relationship between this fact and hot springs in Yellowstone National Park?
Heat-resistant enzymes can be extracted from heat-resistant bacteria growing in Yellowstone National Park hot springs.
Why did life begin on Earth using an anaerobic mode of metabolism?
The atmosphere contained no oxygen at that time
What is the major means of reproduction in prokaryotes?
Binary fission
What is a possible outcome of conjugation in prokaryotic cells?
New genetic combinations within the species
What is the role of nitrogen-fixing bacteria?
Nitrogen-fixing bacteria capture nitrogen gas from the air using hydrogen produce ammonium, which can be used as a nitrogen source by plants
Which disease is caused by the bacterium, Clostridium tetani?
Why are we constantly warned to make sure that hamburger and other meats are cooked thoroughly?
To warn people to provide enough heat to kill Escherichia coli contaminating the meat
What describes a viral particle?
DNA or RNA surrounded by a protein coat
What is the smallest infectious agent that infects humans and exists and replicates as a single protein?
Some bacteria can produce slime that allows them to aggregate into colonies on surfaces. The result is biofilm. How could biofilms be responsible for tooth decay?
Biofilms produce acidic metabolic end products that eat away at tooth enamel causing tooth decay.
What is the end result of bacterial conjugation?
One cell has given a copy of a plasmid to another cell and kept one copy for itself. Both cells end up with a copy of the same plasmid.
Which structure helps bacteria to attach within the tissues that they will infect?
Capsule. The gelatinous capsule that covers some bacteria helps them attach to the tissues that they will infect.
In terms of abundance, what is Earth's predominant form of life?
Prokaryotes. We cannot see them without a microscope, they are often overlooked.
What makes it difficult to distinguish between bacteria and archaea?
They are small and structurally similar. There are only a few structural differences between them.
What is the size range of bacteria and archaea?
0.2 to 10 micrometers
What is the size range of eukaryotes cells?
10 to 100 micrometers
What life form on Earth might be able to survive on the moon?
Bacterial endospores. They can survive extreme conditions.
Why are prokaryotes the most abundant living organisms on earth?
Because of their ability to adapt to a wide range of habitats. Through mutation, Bacteria and Archaea are able to take advantage of virtually all the environmental habitats found on Earth.
What is an advantage of having flagellum?
The ability to migrate towards nutrients. This can cause prokaryotes to disperse into new habitats
Why is it possible for different microorganisms to extract energy not only from carbohydrates and other biological molecules but from a large variety of substances?
Where energy sources were available, life adapted to use them through processes of natural selection.
Why is it that prokaryotic cells evolve more quickly than eukaryotic cells?
Rapid reproduction provides additional opportunity for mutations that are responsible for genetic variability. Some bacterial cells can divide once every 20 min.
What vitamin does our intestinal bacteria synthesize that we absorb for our use?
Vitamin K. It is a fat-soluble vitamin that is important in blood-clotting.
the stimulated breakdown of pollutants by living organisms, particularly bacteria.
Why do virologists consider viruses to be non-living?
They are not cell nor are they composed of cells, the basic components of life. Unlike cells, they have no mechanisms to reproduce themselves.