9/23/2011

Homework:

Do bacteria wrap-up questions. I will paste them all here so there's no confusion. Please answer with complete answers, answering all parts of questions. Original questions are on p. 493-494 (dragonfly book).

11.	What are two distinguishing characteristics of prokaryotes?

12.	Describe the three main cell shapes of prokaryotes.

13.	How do scientists distinguish between Gram-positive and Gram-negative bacteria?

14.	Describe two methods by which prokaryotes move.

15.	How are photoautotrophs similar to chemoautotrophs? How are they different?

16.

State one way in which photoheterotrophs are similar to chemoheterotrophs. 19. What is the role of certain bacteria in changing atmospheric nitrogen into a form usable by plants? 26. Predicting Suppose that bacteria lost the ability to fix nitrogen. How would this affect other organisms? 28. Applying Concepts Why don't foods such as uncooked rice and raisins spoil? 29. Problem Solving Bacteria that live on teeth produce an acid that causes decay. Why do people who do not brush their teeth regularly tend to have more cavities than those who do? 30. Classifying A scientist finds a new organism but is unsure to which kingdom it belongs. The organism is unicellular, has a cell wall containing peptidoglycan, has a circular DNA molecule and ribosomes, but it lacks a nucleus. Based on those characteristics, to which kingdom does it belong? Questions 31–32 An experiment was conducted to determine the effectiveness of different antibiotics against a certain strain of bacteria. Four disks, each soaked in a different antibiotic, were placed in a petri dish where the bacteria were growing. The results are summarized below. 31. Analyzing Data Which antibiotics were the least effective at retarding the growth of the bacteria? Explain your answer using data from the experiment.