26. The best microscopy technique for observing different subcellular structures
ID: 146264 • Letter: 2
Question
26.The best microscopy technique for observing different subcellular structures on the surface of bacteria is
(A) SEM (B) TEM
(C) phase contrast microscopy (D) interference microscopy
(E) fluorescence microscopy
27.Which type of microscopy exploits differences in the refractive index of the specimen, where light is retarded by one-quarter of a wavelength when it passes through a bacterial cell?
(A) SEM (B) TEM
(C) phase contrast microscopy (D) bright-field microscopy
(E) fluorescence microscopy
28.Which type of microscopy should be used to examine bacterial cells that have been Gram stained?
(A) TEM (B) fluorescence microscopy
(C) phase contrast microscopy (D) interference microscopy
(E) bright-field microscopy
29.Which of the following is most abundant in a prokaryotic cell (in dry weight)?
(A) RNA (B) DNA
(C) Polysaccharide (D) Protein
(E) Lipid
30.Which of the following techniques uses the Svedberg unit (S)?
(A) electron microscopy (B) ultracentrifugation
(C) X-ray crystallography (D) genetic analysis
(E) sonication
31.Which of the following is NOT a function performed by the cell membrane or its components?
(A) production of proteins (B) detection of environmental signals
(C) transport of molecules into and out of the cell (D) separation of charge across the membrane
(E) B and D
32.Which of the following statement is true?
(A) Lipopolysaccharides (LPS) are found in the cell wall of Gram-negative bacteria.
(B) Lipopolysaccharides (LPS) are found in the cell wall of Gram-positive bacteria.
(C) Teichoic acids are found in the cell wall of Gram-negative bacteria.
(D) Teichoic acids are found in the cell wall of Gram-positive bacteria.
(E) Cholesterol is found in the cell wall of Gram-negative bacteria.
33.Which of the following is found in Archaeabut not in Bacteria?
(A) Hopanoids (B) Terpenoids
(C) Cholesterol (D) S-layer
(E) Peptidoglycan
34.The glycan chain of archaeal cell wall is made of __________ and __________, while the glycan chain of bacterial cell wall is made of __________ and __________.
(A) peptidoglycan and murein, pseudopeptidoglycan and murein
(B) N-acetylglucosamine and N-acetyltalosaminuronic acid,
N-acetylmuramic acid and N-acetyltalosaminuronic acid
(C) N-acetylglucosamine and N-acetyltalosaminuronic acid,
N-acetylglucosamine and N-acetylmuramic acid
(D) N-acetylglucosamine and N-acetylmuramic acid,
N-acetylglucosamine and N-acetyltalosaminuronic acid
(E) N-acetylmuramic acid and N-acetyltalosaminuronic acid,
N-acetylglucosamine and N-acetyltalosaminuronic acid
35.The sacculus of bacteria is composed primarily of
(A) phospholipids (B) peptidoglycans
(C) carbohydrates (D) amino acids
(E) nucleic acids
36.Lysozyme attacks the following linkage in the bacterial cell wall:
(A) (1,4)-glycosidic bonds
(B) (1,3)-glycosidic bonds
(C) Glycine peptide interbridges
(D) Peptide cross-links between glycan chains
(E) Peptide bonds between L-alanine and D-glutamic acid
Explanation / Answer
26. SEM: Simple Electron Microscopy is used to observe the subcellular components of the bacterial surface. This microscope is used for a typical cell of 10-20 microm.It was the first microscope used to view the smaller micro-organisms.
27. The phase contrast microscopy is the answer. When light passes through a cell.the phase of light is changed according to cells refractive index.When it passes through a dense part of cell it shifts to a thinner region i.e, its phase is shifted.
28. By using a fluorescent microscopy, the illuminating light is a very powerful source to see the stained particles . It passes through two sets of filters where first one to excite the dye at that wavelength and the second blocks the outer light .
29. The prokaryotic cells contain much of protein than that of eukaryotic cells. The ribosomes are responsible for protein production in the cells. They contain a single strand of DNA molecule in the nucleoid.
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