One experiment in phototropism involved cutting off the tips of grass seedlings before exposing them to light from one side. The decapitated seedlings did not bend toward the light. A valid conclusion from this experiment would be that
A) plants cannot engage in photosynthesis without the tip of the plant.
B) light is perceived by the tip of grass plants.
C) a foil cover over the tip of the seedlings would cause them to bend.
D) hormones are produced in all parts of the plant.
Answer: B
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Which of the following is true?
a) The aqueous layer of the tear film is the thickest layer. b) The lipid layer of the tear film is produced by the conjunctival goblet cells. c) The mucin layer is secreted by the glands of Wolfring. d) There are 4 layers of the tear film.
Which of the following statements comparing hemidesmosomes with desmosomes is TRUE?
A. Hemidesmosomes are anchorage junctions but desmosomes are not. B. Hemidesmosomes interact with actin filaments while desmosomes interact with intermediate filaments. C. Both hemidesmosomes and desmosomes associate with integrin, but not cadherin molecules. D. Hemidesmosomes anchor cells to the ECM while desmosomes anchor cells to other cells. E. Hemidesmosomes are found in plant cells while desmosomes are found in animal cells.
Which reaction is most likely to have more products than reactants when the reaction reaches
equilibrium?
a. ?G = ?25 kcal/mol b. ?G = ?50 kcal/mol c. ?G = ?75 kcal/mol d. ?G = ?100 kcal/mol e. They will all have the same ratio of products to reactants regardless of the ?G value.
Which of the following examples is best explained by the process of convergent evolution?
A. The wings of birds and butterflies being used for flight. B. Wolves and coyotes both producing milk for their young. C. Both mice and rats having a tail. D. A human cell and a fruit fly cell both going through the process of transcription and translation in order to produce a gene.