Researchers enter a virus genome sequence into the database, which then sorts through the tens of thousands of drugs already in existence to find the best one to fight the invader. In addition, they mutate very easily. As illustrated in Figure Pili singular, pilus are submicroscopic, hairlike structures that are made of protein. Bacteria move so quickly; the electrons stun the bacteria. Viruses are living organisms.

Once the virus successfully attaches to a host cell, the genetic material of the virus enters the cytoplasm of the host. Discuss possible rationales that taxonomists might have used when deciding to group prokaryotes into two distinct domains instead of in one group. Viruses have no organelles to take in nutrients or use energy, they cannot make proteins, they cannot move, and they cannot replicate on their own. Bacteria are decomposers, returning vital nutrients to the environment. Because a bacterial cell usually only produces one endospore, this is considered a survival mechanism rather than a type of reproduction. Draw the stages of the two cycles under the flaps. The viral genes might remain dormant for months or years.

Most viruses range in size from 5 to nanometers a nanometer is one billionth of a meter. Protein is made directly from viral RNA. Data Analysis lab Analyze Which means of reproducing shown here exchanges genetic information?

Chapter Bacteria and Viruses

The virus now uses the host cell to replicate by either the lytic cycle or the lysogenic cycle. Although this mode of transmission is not agreed upon, the United States government has strict regulations concerning the nujber of cattle and beef from other countries.


Prokaryotic flagella are made of filaments, unlike the flagella of eukaryotes that are made of microtubules. Chromosomes The chromosomes in prokaryotes are arranged differently than the chromosomes found in eukaryotic cells.

In some cases, the entire virus enters the cell and the capsid is broken down quickly, exposing the genetic material. These bacteria have enzymes that can convert nitrogen gas into nitrogen compounds by a process called nitrogen fixation. Some of these bacteria live in the soil.

Some archaebacteria called thermoacidophiles thur muh uh SIH duh filz live in hot, acidic environments including sulfur hot springs shown in Figure These organisms are obligate anaerobes, which means they cannot classifidation in the presence of oxygen. Prokaryotes are microscopic, unicellular organisms. Many heterotrophic eubacteria are saprotrophs, or saprobes. Add this document to collection s.

Hypothesize What other hostile places might you find archaebacteria? Compare and contrast similarities and differences in the replication of a herpes simplex virus with a human immunodeficiency virus. These organisms are called chemoautotrophs. Choose four different slides numbber bacteria that have been stained to show cell wall differences. Most virologists spend many hours in the laboratory conducting experiments.


critical thinking diagram worksheet 18-1 classification of bacteria by shape and number

Tobacco mosaic virus causes disease in tobacco leaves. What data could scientists lf, under the biological species concept, to show that they are the same species?

critical thinking diagram worksheet 18-1 classification of bacteria by shape and number

Which describes the role of an endospore in bacteria? Endospores When environmental conditions are harsh, some types of bacteria produce a structure called an endospore.

Clzssification why a doctor would not prescribe an antibiotic to treat the flu. Chemoautotrophs A second type of bacteria that are autotrophs do not require light for energy.

Viruses are living organisms. Draw a diagram of a virus and label the parts. The viral genes instruct the host cell to manufacture capsids and assemble new viral particles.

Chapter 18: Bacteria and Viruses

Your first challenge is to swallow microbes. Prokaryotes have a variety of survival mechanisms. But now there is a new hero on the field, ghinking that might make the development of antiviral drugs as easy as following a recipe. Bacteria are even used in the production of chocolate. Virus structure Figure Specify an example of an ancestral character and a derived character among angiosperms.