α-helices and β-pleated sheets occur at what protein structure level?

Which type of inhibition can be reversed by increasing the substrate concentration? _______

At what protein structure level is a folded protein that functions as an enzyme without needing any additional subunits?

Name the main substance translocated in the phloem of most plants (the specific molecule). _______

What is the name for the explanation that describes how water moves up through a plant stem (xylem) against the pull of gravity?

All eukaryotic cells also have a cytoskeleton consisting of fibrous proteins.  What are the  hollow tubes made of columns of tubulin subunits called?  (An example of what these are involved with is forming the spindle during mitosis)  

Name the cells in this type of tissue that are thin-walled, metabolically active cells (e.g. carrying out photosynthesis, e.g. non-photosynthetic but storing starch, etc.). _______

As pH increases from its optimal value for an enzyme catalyzed reaction, the reaction rate will

The preceding questions asked about pathways by which water crosses a root cortex. Which of the preceding questions refer(s) to “cellular” pathway(s)? (Note the letters “a”, “b”, and “c” identifying each question above.  

Name the cells in this type of tissue that have thick primary cell walls to provide flexible support for growing parts of the plant. _______