1. With which of the following statements concerning the stiffening of aging tissues would the author most likely agree?(A) It is caused to a large degree by an increased rate of cell multiplication.
(B) It paradoxically both helps and hinders the longevity of proteins in the human body.
(C) It can be counteracted in part by increased ingestion of glucose-free foods.
(D) It is exacerbated by increased enzymatic glycosylation.
(E) It probably involves the nonenzymatic glycosylation of proteins.
2. According to the passage, which of the following statements is true of the process that discolors and toughens foods?(A) It takes place more slowly than glycosylation in the human body.
(B) It requires a higher ratio of glucose to protein than glycosylation requires in the human body.
(C) It does not require the aid of enzymes to attach glucose to protein.
(D) It proceeds more quickly when the food proteins have a molecular structure similar to that of crystallin proteins.
(E) Its effectiveness depends heavily on the amount of environmental moisture.
3. According to the passage, which of the following is characteristic of enzymatic glycosylation of proteins?(A) AGE’s are formed after a period of months or years.
(B) Proteins affected by the process are made unstable.
(C) Glucose attachment impairs and stiffens tissues.
(D) Glucose is attached to proteins for specific purposes.
(E) Amino groups combine with aldehyde groups to form Schiff bases.
4. Which of the following best describes the function of the third paragraph of the passage (lines 19-29)?(A) It offers evidence that contradicts the findings described in the first two paragraphs.
(B) It presents a specific example of the process discussed in the first two paragraphs.
(C) It explains a problem that the researchers mentioned in the second paragraph have yet to solve.
(D) It evaluates the research discoveries described in the previous paragraph.
(E) It begins a detailed description of the process introduced in the previous two paragraphs.
5. The passage suggests that which of the following would be LEAST important in determining whether nonenzymatic glycosylation is likely to have taken place in the proteins of a particular tissue?(A) The likelihood that the tissue has been exposed to free glucose
(B) The color and spectrographic properties of structures within the tissue
(C) The amount of time that the proteins in the tissue have persisted in the body
(D) The number of amino groups within the proteins in the tissue
(E) The degree of elasticity that the tissue exhibits
6. If the hypothesis stated in lines 56-58 is true, it can be inferred that the crystallin proteins in the lenses of people with cataracts(A) have increased elasticity
(B) do not respond to enzymatic glycosylation
(C) are more susceptible to stiffening than are other proteins
(D) are at least several months old
(E) respond more acutely than other proteins to changes in moisture levels
7.According to the passage, which of the following statements is true of Amadori products in proteins?(A) They are more plentiful in a dehydrated environment.
(B) They are created through enzymatic glycosylation.
(C) They are composed entirely of glucose molecules.
(D) They are derived from Schiff bases.
(E) They are derived from AGE’s.