Contrast in microscopy is most commonly achieved by:
a. changing objectives for various specimens.
b. increasing the resolution or resolving power.
c. staining techniques.
d. adding a blue filter to the light path.
C
Various staining techniques are used to increase contrast and make objects appear more visible.
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Which of the following organelles can be found in all prokaryotes and eukaryotes?
a. ribosomes b. cell membrane c. capsule d. ribosomes and cell membrane
Describe two ways in which the unique membrane lipids of archaea protect them from environmental stress: one for pH and one for temperature.
What will be an ideal response?
Phosphofructokinase is regulated by a number of factors, including high levels of ATP. Why is this enzyme regulated by ATP levels?
A. If ATP levels are high, this provides a mechanism to directly inhibit the Citric acid cycle, thus preventing further generation of NADH, FADH2 and ATP molecules that are not needed. B. If ATP levels are high, this provides a mechanism to directly inhibit the electron transport chain, thus preventing the formation of a proton gradient in the intermembrane space of mitochondria. C. If ATP levels are high, it is important to directly inhibit the reaction that commits the substrate to glycolysis to allow the substrate to be available for other reactions, since the cell has ample energy. D. If ATP levels are high, it is important to inhibit ATP synthase, and phosphofructokinase directly inhibits ATP synthase.
What information would be most useful for studying the evolution of a worm species?
A. the diet of birds in the area that eat the worms B. similarities in histone genes between other worms and the studied worm C. the locations where the worms are found comparisons with other invertebrates in the same area