Bacteria are extremely small living things. While we measure our own sizes in inches or centimeters, bacterial size is measured in microns. One micron is a thousandth of a millimeter a pinhead is about a millimeter across. Rod shaped bacteria are usually from two to tour microns long, while rounded ones are generally one micron in diameter Thus if you enlarged a founded bacterium a thousand times, it would be just about the size of a pinhead. An adult human magnified by the same amount would be over a mile(1.6 kilometers) tall.
Even with an ordinary microscope, you must look closely to see bacteria. Using a magnification of 100 times, one finds that bacteria are barely visible as tiny rods or dots One cannot make out anything of their structure. Using special stains, one can see that some bacteria have attached to them wavy – looking “hairs” called flagella. Others have only one flagellum. The flagella rotate, pushing the bacteria though the water. Many bacteria lack flagella and cannot move about by their own power while others can glide along over surfaces by some little understood mechanism.
From the bacterial point of view, the world is a very different place from what it is to humans To a bacterium water is as thick as molasses is to us. Bacteria are so small that they are influenced by the movements of the chemical molecules around them. Bacteria under the microscope, even those with no flagella, often bounce about in the water. This is because they collide with the water molecules and are pushed this way and that. Molecules move so rapidly that within a tenth of a second the molecules around a bacterium have all been replaced by new ones even bacteria without flagella are thus constantly exposed to a changing environment.
- Which of the following is the main topic of the passage?
(A) The characteristics of bacteria (B) How bacteria reproduce
(C) The various functions of bacteria (A) How bacteria contribute to disease
- Bacteria are measured in
(A) inches (B) centimeters (C) microns (D) millimeters
- Which of the following is the smallest?
(A) A pinhead (B) A rounded bacterium
(C) A microscope (D) A rod-shaped bacterium
- According to the passage, someone who examines bacteria using only a microscope that magnifies 100 times would see
(A) tiny dots (B) small “hairs”
(C) large rods (D) detailed structures
- The relationship between a bacterium and its flagella is most nearly analogous to which of the following?
(A) A rider jumping on a horse’s back (B) A ball being hit by a bat
(C) A boat powered by a motor (D) A door closed by a gust of wind
- In line 16, the author compares water to molasses, in order to introduce which of the following topics?
(A) The bacterial content of different liquids
(B) What happens when bacteria are added to molasses
(C) The molecular structures of different chemicals
(D) How difficult it is for bacteria to move through water
One of the most popular literary figures in American literature is a woman who spent almost half of her long life in China, a country on a continent thousands of miles from the United States. In her lifetime she earned this country’s most highly acclaimed literary award: the Pulitzer Prize, and also the most prestigious form of literary recognition in the world, the Nobel Prize for Literature. Pearl S. Buck was almost a household word throughout much of her lifetime because of her prolific literary output, which consisted of some eighty – five published works, including several dozen novels, six collections of short stories, fourteen books for children, and more than a dozen works of nonfiction. When she was eighty years old, some twenty – five volumes were awaiting publication. Many of those books were set in China, the land in which she spent so much of her life. Her books and her life served as a bridge between the cultures of the East and the West. As the product of those two cultures she became as the described herself, “mentally bifocal.” Her unique background made her into an unusually interesting and versatile human being. As we examine the life of Pearl Buck, we cannot help but be aware that we are in fact meeting three separate people: a wife and mother, an internationally famous writer and a humanitarian and philanthropist. One cannot really get to know Pearl Buck without learning about each of the three. Though honored in her lifetime with the William Dean Howell Medal of the American Academy of Arts and Letters in addition to the Nobel and Pulitzer prizes. Pearl Buck as a total human being, not only a famous author. is a captivating subject of study.
- What is the author’s main purpose in the passage?
(A) To offer a criticism of the works of Pearl Buck.
(B) To illustrate Pearl Buck’s views on Chinese literature
(C) To indicate the background and diverse interests of Pearl Buck
(D) To discuss Pearl Buck’s influence on the cultures of the East and the West
- According to the passage, Pearl Buck is known as a writer of all of the following EXCEPT
(A) novels (B) children’s books (C) poetry (D) short stories
- Which of the following is NOT mentioned by the author as an award received by Pearl Buck?
(A) The Nobel Prize (B) The Newberry Medal
(C) The William Dean Howell medal (D) The Pulitzer prize
- According to the passage, Pearl Buck was an unusual figure in American literature in that she
(A) wrote extensively about a very different culture
(B) published half of her books abroad
(C) won more awards than any other woman of her time
(D) achieved her first success very late in life
- According to the passage, Pearl Buck described herself as “mentally bifocal” to suggest that she was
(A) capable of resolving the differences between two distinct linguistic systems
(B) keenly aware of how the past could influence the future
(C) capable of producing literary works of interest to both adults and children
(D) equally familiar with two different cultural environments
- The author’s attitude toward Pearl Buck could best be described as
(A) indifferent (B) admiring (C) sympathetic (D) tolerant