Dissecting-Microscopes

Items 259-264

admin — Tue, 22 Apr 2008 02:13:02 +0000

259. The projections indicated as letter B are

(A)    cilia
(B)    mcrovilli
(C)    flagella
(D)    basal bodies
(E)    focal adhesion points (more…)

Items 254-258

admin — Tue, 22 Apr 2008 02:10:38 +0000

254. The elongate cellular projection labeled A is a

(A)    flagellum
(B)    nerve axon
(C)    pseudopodium
(D)    cilium
(E)    microvillus

255. Structure labeled C is

(A)    Golgi Apparatus
(B)    pseudopodium
(C)    cilium
(D)    mcrovillus (more…)

Items 247-253

admin — Tue, 22 Apr 2008 02:09:02 +0000

247. Which statement is LEAST ACCURATE?

(A)    The polarity of microtubules is related to the fact that the tubulin subunit is a heterodimer of ? and ? subunits.
(B)    Actin filaments often associate with special patches of the plasma m mbrane.
(C)    Kinesin is an ATPase that may interact with microtubules.
(D)    Intermediate filaments are assembled in the intermediate zone of the mitotic spindle.
(F)    While some microtubules may be rapidly assembled or disassembled, those of cilia and flagella are quite stable once assembled to form the axoneme. (more…)

Items 243-246

admin — Tue, 22 Apr 2008 02:05:43 +0000

243. Microfilaments

(A)    are 4-7 nm in diameter
(B)    contain the proteins actin and keratin
(C)    cause the anterograde movement of mitochondria in axons
(D)    form the dense mass of filaments attaching to desmosomes
(E)    bind chromosomes to the mitotic spindle (more…)

Items 237-242

admin — Tue, 22 Apr 2008 02:03:58 +0000

Tissue-culture microscope 3.6 is a scanning electron micrograph of the apical surface on the epithelial cells lining the trachea. For each numbered item of identity or functions, choose the ONE best answer.

237. The structures labeled A are

(A)    cilia
(B)    flagella
(C)    microvilli
(D)    microtubules
(E)    collagen fibers

238. The structures labeled B are (more…)

Items 232-236

admin — Tue, 22 Apr 2008 02:02:37 +0000

Tissue-culture microscope 3.5 is a freeze-fracture electron micrograph of the apical surfaces of epithelial cells lining the lumen of the ileum. For each numbered item naming, or stating the function of a specific structure, choose the ONE best answer.

232. The surface projections indicated by the

(A)    microveilli
(B)    cilia
(C)    basal bodies
(D)    desmosomes
(E)    flagella (more…)

Items 227-231

admin — Mon, 21 Apr 2008 00:30:31 +0000

Examine the transmission electron micrograph of skeletal muscle in Tissue-culture microscope 3.4 below. Match the labeled structure in the micrograph with the most appropriate description of its microscopic anatomy or physiological role.

227. These structures are the ends of individual sacromeres. They are regions rich in ?-actin.

228. These structures are regions of overlap between actin-rich thin filaments and mysosin rich thick filaments.

229. Thse structure produce ATP, which is hydrolyzed to provide the energy for muscle contraction. (more…)

Items 222-226

admin — Mon, 21 Apr 2008 00:09:41 +0000

Examine the high power transmission electron micrograph of cell surface projections in Tissue-culture microscope 3.3 below. These projections are cut perpendicular to their long axis. For each numbered item of a functional role choose the most appropriate component labeled with a letter in the electron micrograph. (more…)

Items 218-221

admin — Mon, 21 Apr 2008 00:02:06 +0000

Examine the high power transmission electron micrograph in Tissue-culture microscope 3.2 below. It is an array of long hollow structures cut perpendicular to their long axis. The diameter of each hollow structure is 25 nm.

218. Each individual hollow structure is a

(A)    microfilament
(B)    ciliary axoneme
(C)    microtubule
(D)    thick filament of muscle
(E)    intermediate filament (more…)

Items 215-217

admin — Mon, 21 Apr 2008 00:00:47 +0000

For each item, choose the most appropriate answer.

215.     The axoneme of a cilium
(A)     has 9 single microtubules arranged around a central pair of doublet microtubules
(B)     contains several ATPase, including myosin
(C)     is very similar to the oxoneme of a sperm flagellum
(D)     shortens by about 25% when stimulated by Ca 2+ ions
(E)      normally is activated by binding of acetylcholine at the tip of the   cilium (more…)