18) Radioisotopes are frequently used to label molecules in a cell. The fate of
ID: 188499 • Letter: 1
Question
18) Radioisotopes are frequently used to label molecules in a cell. The fate of atoms and molecules in a 18) ce'll can then be followed. Assume Saccharomyces cerevisiae is grown in a nutrient medium containing the radioisotope 3% After a 48-hour incubatir, the 35S would most likely be found in the S. cerevisiae's A) nucleic acids. B) proteins C) carbohydrates D) water E) lipids 19) A scientist wants to perform a test that will indicate whether a nucleic acid sample is composed of 19) RNA or DNA. Testing for the presence of which of the following is most appropriate in this situation? D) guanine ) nitrogen A) thymine B) phosphate C) uracil 20) 20) Structurally, ATP is most like which type of molecule? 21) A virus measures 100 nm in length. What is its length in m? 22) Which of the following places the steps of the Gram stain in the correct order? A) carbohydrate B) lipid C) nucleic acid D) protein 21)_ B)10 C)0.001 m D) 1 m E) 0.01 22) 1-Alcohol-acetone 2-Crystal violet 3-Safranin 4-lodine A) 1-3-2-4 B)2-1-4-3 )1-2-3-4 D) 4-3-2-1 E)2-4-1-3 23) 3) Which of the following pairs is mismatched? A) crystal violet - simple stain B) methylene blue - simple stain C) acidic dye -capsule stain D) nigrosin-negative stain E) basic dye -negative stairn 24) Which microscope achieves the highest magnification and greatest resolution? A) phase-contrast microscope B) electron microscope C) darkfield microscope D) fluorescence microscope E) compound light microscope hich of the following correctly traces the path of light through the compound microscope? A) light source; condenser; specimen; objective lens; ocular lens B) condenser; light source; specimen; ocular lens, objective lens C) light source; condenser; objective lens; specimen; ocular lens D) light source: specimen; condenser, objective lens; ocular lens E) condenser, light source; specimen; objective lens; ocular lens 25)Explanation / Answer
Answer-
18)
B. Proteins
As S35 will lebel the proteins where it will synthesizemethionine in protein
19)
C. Uracil
because the difference between uracil and thiamine is that Thaimine is present in DNA which is a methylation at position 5
20)
c. Nucleic acid
because ATP stands for adenosine triphosphate and three phospate groups bound to Adenosite form ATP
21)
A) 0.1 uM
because 1 uM= 1000 nm
so 0.1 um=100nm
22)
E) 2-4-1-3
as the procedure of gram staining is add crystal violate, then add iodine solution , then alcohol or acetone wash & then counter stain by safranin
23)
D. negrosin- negative is amiss matched ,
as stain cells that are too delicate to be heat-fixed and other are simple staing.
24)
B. Electron microscope
25)
A.
light source- condenser- specimen- objective lence-occular lense.
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