Activation results in the lytic cycle. Bacteria are the most common organisms in your environment. It would take about 10, cold viruses to span the period at the end of this sentence. In humans, some diseases, such as those listed in Table Adenovirus infection causes the common cold, and influenza virus is responsible for causing the flu. Then, the DNA moves into the nucleus of the host cell and integrates into a chromosome.

Many times the genes are not activated until later. Methanogens even thrive in the gastrointestinal tract of humans and other animals and are responsible for the gases that are released from the lower digestive tract. Prokaryotes belong to two domains. Suppose that two mosquitoes are classified as different species using the typological species concept. Some cancer-causing viruses also belong to this group. Some organisms get their energy from the cells and tissues of dead organisms and are called decomposers or detrivores.

Which is the correct identification for the bacteria shown above? Virus structure Figure Other archaebacteria called halophiles HA luh filz live in very wnswers environments. The common cold and influenza are two examples of widespread viral diseases that are active infections.

Many species of bacteria can cause diseases. You can add this document to your saved list Sign in Available only to authorized users. Error Analysis Compare and contrast the observations and measurements collected by your group with the data from the experiments designed by other groups.


This is one way of transferring the resistance to antibiotics. Many times the genes are not activated until later. Imagine that a patient in a hospital has died mysteriously.

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

Some cancer-causing viruses also belong to this group. Differences between eubacteria and archaebacteria The cell walls of the eubacteria contain peptidoglycan, but the cell walls of archaebacteria do not.

Many prokaryotes also have at least one smaller piece of DNA, called a plasmid, which also has a circular arrangement. The ribosomal proteins in the achaebacteria are similar to those of eukaryotic cells. Shape There are three general shapes of prokaryotes, as shown in Figure Anaerobic bacteria do not use oxygen for growth or metabolism; these bacteria are called obligate anaerobes.

Bacteria also can cause disease in plants, and most plants can become infected. STEP 2 Fold it in half again as shown. Widely diffused or prevalent.

These new viruses leave the cell by exocytosis or by causing the cell to burst, or lyse, releasing new viruses that are free to infect other cells. The new viruses then leave the cells. Prokaryotic cells do not have a nucleus. Bacilli Movement Although some prokaryotes are stationary, other bacteria use flagella for movement.

Careers in Biology Microbiologist Chapter 19 Protists ” ‘ DEA Protists are a diverse group of unicellular and multicellular organisms that do not necessarily share the same evolutionary history. Researchers enter a virus genome sequence into the owrksheet, which then sorts through the tens of thousands of drugs already in existence to find the best one to fight the invader.


Chapter Bacteria and Viruses

In some cases, the entire virus enters the cell and the capsid is broken down quickly, exposing the genetic material. Explain how the concepts of observation, inference, and skepticism differ. Without nitrogen fixation, far more fertilizer would be needed for growing plants. Many scientists think that prokaryotes were the first organisms on Earth.

Chapter 18: Bacteria and Viruses

Some of these bacteria live in the soil. The word prokaryote is a Greek word that means before a nucleus.

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

Open Ended Make an argument vlassification or against the following statement: Virus size Viruses are some of the smallest disease-causing structures that are known. Mutations If the environment changes and bacteria are not well adapted to the new conditions, extinction of the bacteria is a possibility. But now there is a new hero on the field, one that might make the development of antiviral drugs as easy as following a recipe.