Which of the following mechanisms best explains how xylem sap moves up against the downward pull of gravity?
A) cohesion-tension hypothesis
B) gravitropism
C) phototropism
D) expenditure of ATP
A
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Members of which fungal phylum are the only ones to produce motile spores?
a. Glomeromycota b. Basidiomycota c. Chytridiomycota d. Zygomycota e. Ascomycota
List several functions of epithelial tissues
What will be an ideal response?
In the figure above, the two strands have
separated in step "b" because
a. the sugar-phosphate bonds were broken. b. the hydrogen bonds between bases were broken. c. energy from primers pushed the bases apart. d. the bases, being negatively charged, repelled each other. e. proteins were inserted between each pair of bases.
Quaternary structure of a protein refers to ________
A) the sequence of amino acids in a polypeptide B) alpha-helical or beta-sheet arrangements of protein structure C) three-dimensional coil of a polypeptide around itself D) the association of multiple polypeptide subunits to form a functional protein E) the number of amino acids in a polypeptide chain