Name: 
 

Objective 3 Practice


Modified True/False
Indicate whether the sentence or statement is true or false.  If false, change the identified word or phrase to make the sentence or statement true.
 

1. 
A root cap is a tiny, single-celled extension of an epidermal cell that increases the surface area of the root and absorbs water and minerals. __________________

 

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
 
 
Robert Koch
In the nineteenth century Robert Koch scientifically investigated the transmission of diseases. He proposed a procedure that would enable a person to determine if a specific microorganism caused a given disease. The first four steps of this procedure are listed below:

1.      Microbes must be isolated from an infected host organism.
2.      The isolated microbes are then grown in a pure culture.
3.      The microbes from the pure culture are injected into a new host.
4.      If the new host contracts the disease, the microbes must be isolated from the new host and grown in a new culture.
 

2. 
What final step should be taken to prove that these specific microbes cause the given disease?
a.
Mix the microbes from the new and old cultures.
b.
Inject diseased organisms with the microbes from the new culture.
c.
Compare the original microbes with the microbes in the new culture.
d.
Inject an organism immune to the disease with microbes from the new culture.
 

3. 
Robert Koch isolated bacteria and injected them into an animal to see if they caused a disease. His studies led most directly to the discovery of
a.
vitamins.
c.
nucleic acids.
b.
antibiotics.
d.
genetic diseases.
 

4. 
Use the diagram of the plant tip exposed to light to answer the following question.
objective_3_files/i0070000.jpg
An experiment was set up to test the effects of light on the growing tip of a plant. The diagram shows a longitudinal section of the growing plant tip.

Which of these observations correctly describes the results?
a.
The cells farther away from the light source are longer than the cells facing the light.
b.
The walls of the cells farther away from the light source are thicker.
c.
There are more cells on the side of the plants facing away from the light source.
d.
The cells in the center of the plant are more flexible than cells on the sides.
 
 
      In the recent past, many of the Great Lakes were dying lakes. Toxic chemicals, such as PCBs (polychlorinated biphenyls), had been dumped into the lakes. Many of these chemicals entered the food chain. Deformed gull chicks were some of the first warning signs.

      A simplified food chain in the Great Lakes is shown in the figure below. The numbers show the concentration of PCB (in parts per million) in the tissues of the various organisms.
objective_3_files/i0080000.jpg
Figure adapted from G. Tyler Miller, Jr., Living in the Environment, 7th edition. © 1992 by Wadsworth Publishing Company.

      In addition, nitrates and phosphates from farmland and household detergents ran off into the lakes. These nutrients caused rapid growth of algae and other aquatic plants. When the plants died, they were decomposed by bacteria, a process that uses oxygen. Eventually, the level of dissolved oxygen in deeper waters fell, resulting in the decline or elimination of many native species.

      Today, the water quality of the Great Lakes is much improved.
 

5. 
Which group of organisms in the figure provides energy, either directly or indirectly, to all the other organisms in the food chain?
a.
phytoplankton
c.
rainbow smelt
b.
zooplankton
d.
herring gulls
 

6. 
Which of the following best explains why herring gull chicks were one of the first species to exhibit the effects of pollution, according to the figure?
a.
Toxins decrease in concentration as one moves up a food chain.
b.
Toxins increase in concentration as one moves up a food chain.
c.
Toxins have less of an effect on herring gulls than on other species.
d.
Toxins affect terrestrial organisms more se