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Monday, June 29, 2009

GRE biochemistry Biology test

In This Gre biochemistry and biology test Chose the right answer

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17. Given the same temperature of O0C, which of the following liquids has the highest surface tension?
1. benzene
2. ethanol
3. acetone
4. water
5. Glycerine

18. Which property of any liquid can support the weight of a needle?
1. polar bonds
2. polarity
3. high surface tension
4. high heat of vaporization
5. capillarity

19. Which property of water is best demonstrated in the rise of water within xylem vessels of plants?
1. polarity
2. surface tension
3. capillarity
4. high specific heat
5. proton pump

20. Water spontaneously rises through capillary tubes. What is the relationship between the inside diameter of the tubes and the height of the water column?
1. inversely proportional, i.e. the smaller the diameter, the lower is the water column
2. directly proportional, i.e. the bigger the diameter, the higher the water column
3. no relationship, i.e. the rise of water is independent of the diameter
4. negative relationship, i.e. the bigger the diameter, the failure of water to rise
5. positive relationship, the smaller the diameter, the faster the rise of water

21. How much heat is needed to evaporate a liquid with high heat of vaporization compared to those having low heat of vaporization?
1. more heat
2. less heat
3. equal heat
4. no heat
5. none of the above

22. In your experiment using a continuous membrane of water, the membrane is permeable in which condition?
1. membrane of water sandwiched between chloroform and ether
2. membrane of water sandwiched between chloroform and xylene
3. membrane of water sandwiched between chloroform and acetone
4. membrane of water sandwiched between chloroform and ethyl alcohol
5. all of the above

23. What is the process by which liquids pass through the water membrane?
1. osmosis
2. diffusion
3. absorption
4. differential permeability
5. solubility

24. The water potential of a solution may be expressed as
1. atmospheres (atmp)
2. megaPascals (MPas)
3. bars
4. grams/cm3
5. all of the above

25. Which of the following is the expression of the water potential of pure water?
1. ψ <>0
3. ψ = 0
4. ψ ± 0
5. ψ ≤ 0

26. Name of the process that results on the change in weight of potato cylinders soaked in different concentrations of sucrose solutions?
1. diffusion
2. absorption
3. permeability
4. turgidity
5. flaccidity

Continue the GRE biochemistry Biology test

27. When potato cylinders were soaked in 0.7 M sucrose solution, what caused the percent weight change?
1. accumulation of water
2. accumulation of sucrose
3. accumulation of both water and sucrose
4. exit of water
5. exit of organelles

28. Which of the following has the most negative water potential?
1. potato cylinders previously soaked in distilled water
2. potato cylinders soaked in 0.1 M sucrose solution
3. a plant after a heavy rain
4. wilted plant in dry soil
5. none of the above

29. Cytoplasmic and cell membranes of lower epidermal cells in Rhoeo spathacea are permeable to
1. weak acid or base
2. strong acid or base
3. water
4. anthocyanin
5. A, B and C are correct

30. Which of these plant pigments is colored pink to blue-violet?
1. chlorophyll
2. xanthophylls
3. carotenoids
4. anthocyanin
5. none of the above

31. Anthocyanin can diffuse through
1. vacuolar membrane or tonoplast
2. cell membrane
3. cell wall
4. all of the above
5. none of the above

32. What were the findings in your experiment regarding the pH of anthocyanin?
1. acidic
2. basic
3. neutral
4. immeasurable
5. none of these

33. In which sugar solution does Hydrilla cells most likely undergo plasmolysis?
1. 0.1 M
2. 0.2 M
3. 0.4 M
4. 0.6 M
5. 0.8 M

34. Plasmolysis occurs if a plant cell (ψ < 0) is placed in
1. a solution with more negative water potential
2. a solution with water potential equal to zero
3. a solution with less water potential
4. hypotonic solution
5. any of the above

35. What is/are the base(s) of the differences of the membrane permeability?
1. size of the diffusing molecules
2. solubility of diffusing molecules with membrane molecules
3. concentration gradient
4. all of the above
5. none of the above

36. When the water potential of the plant cell sap is equal to that of its surrounding solution, it is said to be in equilibrium thus
1. the cell is turgid
2. there no net movement of water
3. the cell is in incipient plasmolysis
4. osmotic potential of cell sap is equal to pressure potential
5. none of the above

37. When the lower epidermal cells of Rhoeo spathacea was added with a strong base like ammonium hydroxide, what resulted
1. cytoplasm shrank and colored dark pink
2. cytoplasm shrank and colored greenish blue
3. cytoplasm become turgid and colored pink
4. cytoplasm become turgid and colored greenish blue
5. none of the above

38. Catalase is an enzyme named according to
1. its substrate
2. its effectiveness
3. its action
4. all of the above
5. none of the above

39. Which of these combinations of enzymes and substrate give the highest (maximum) effervescence?
1. sand + hydrogen peroxide
2. water + hydrogen peroxide
3. potato cylinder + hydrogen peroxide
4. macerated potato cube + hydrogen peroxide
5. none of the above

40. How would you know that there is breakdown of hydrogen peroxide is caused by the action of an enzyme catalase?
1. no evolution of oxygen gas
2. considerable evolution of oxygen gas
3. evolution of carbon dioxide gas
4. utilization of oxygen gas
5. evolution of hydrogen gas
41. Catalase activity is effective only at which pH?
1. slightly acidic
2. strongly acidic
3. slightly basic
4. strongly basic
5. neutral
42. In a chemical reaction between enzyme and its substrate what are produced?
1. reaction products
2. heat
3. reactants
4. all of the above
5. both A and B

43. How many calorie(s) is needed to raise the temperature of 1 g of water by 10 C?
1. one calorimeter
2. one calorie
3. one Kilocalorie
4. one centigrade
5. one Celsius
44. How does temperature affect activity of catalase on hydrogen peroxide?
1. At very low temperature, enzyme activity is very low.
2. As the temperature increases, catalase activity rises because hydrogen peroxide molecules move faster and reach the active sites of the enzyme molecules more rapidly.
3. Enzyme activity reaches at a maximum at the optimum temperature.
4. A further increase in temperature results in the drastic drop in enzyme activity because the enzyme molecules being proteins, are denatured and cannot work properly
5. all of the above are true.

45. In testing the product of photosynthesis, why was the leaf boiled before it was put in alcohol?
1. To ensure that the leaf undergone photosynthesis so that starch is accumulated.
2. To stimulate the leaf to hasten the process of photosynthesis.
3. To kill the cells and stop further chemical reactions that might use the stored starch.
4. To extract the chlorophyll that might block the location of starch.
5. All of the above are correct.

46. In the variegated gumamela leaf subjected to Iodine test for starch, what can you observe?
1. The originally white areas that turned brown showing starch is present.
2. The originally white areas that turned green showing starch is present.
3. The originally green areas have blue-black color indicating location of starch.
4. The originally green areas which turned brown indicating location of starch
5. Both green and white areas turned brown indicating the presence of starch.

47. Why is variegated leaf normally used in the experiment to verify the necessity of chlorophyll in photosynthesis?
1. It is efficient in the process of photosynthesis.
2. It has green regions with chlorophyll and non-green regions without chlorophyll.
3. It has even distribution of chlorophyll although not visible with the naked eye
4. It is the only leaf that responds to Iodine test for starch.
5. all of the above.

48. If the variegated leaf tested for starch show that starch may also be detected in both green and non-green regions. How would you explain this?
1. The sugar made in the green regions by photosynthesis may have been transported to the non-green region and stored as starch.
2. The direct product of photosynthesis in the non-green regions is in the form of starch.
3. The starch in the non-green region is not a product of photosysnthesis but by another process.
4. The starch in both green and non-green regions is not true starch.
5. Photosynthesis in the leaf does no always involve chlorophyll.

49. The pigment chlorophyll is most soluble in
1. acetone
2. 95% ethyl alcohol
3. water
4. xylol
5. none of the above

50. Fluorescence of chlorophyll is an inefficient utilization of light energy because
1. no potential chemical energy is produced
2. excess energy of its electrons is dissipated as heat and light energy
3. energy of its electrons is converted to ATP
4. all of the above
5. both A and B are correct

51. Chlorophyll molecule is soluble in an organic solvent because of its
1. carbon rings
2. pophyrin rings
3. hydrocarbon tail
4. benzene rings
5. all of the above

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