Foods can be preserved in many ways by slowing or preventing bacterial growth. Which of these methods should be LEAST effective at inhibiting bacterial growth?
A) Refrigeration: slows bacterial metabolism and growth.
B) Closing previously opened containers: prevents more bacteria from entering, and excludes oxygen.
C) Pickling: creates a pH at which most bacterial enzymes cannot function.
D) Canning in heavy sugar syrup: creates osmotic conditions that remove water from most bacterial cells.
B
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During prophase I of meiosis, a physical exchange of parts of homologous chromosomes can occur and is called a ____
Fill in the blank with the appropriate word.
How does auxin actually cause stems to curve towards the light?
A. In the presence of light, auxin moves toward the light source and activates a protein that binds to DNA and starts enzyme production. B. In the presence of blue light, auxin triggers additional photosynthesis and growth. C. In the presence of light, auxin increases the formation of hydrolytic enzymes that release energy needed for growth purposes. D. In the presence of unidirectional light, auxin moves to the shady side and activates an ATP-driven proton pump that results in weakened cell walls and eventual elongation. E. In the presence of light, auxin increases the turgor pressure of the cell and accelerates growth.
Swordtail fish are known for the long extensions on the males' tails. What types of experiments might help you determine whether the females are using visual input about tail length to choose between males? (Check the best three)
A. Add artificial tails of different lengths to females and determine their response to normal males. B. Measure hormone levels in males who have different size tails. C. Create artificial fish models with different size tails and measure female response. D. Add artificial tails of different lengths to male platys (a similar fish without tail extensions), and measure female response. E. Trim the tails of male fish to different lengths and measure female response. F. Measure sperm count in males who have different size tails.
An instrument that magnifies slight differences in the refractive index of cell structures is called a (n) ________ microscope.
A. densitometric B. electron C. fluorescence D. phase-contrast