11. You are a research scientist for the National Institutes of Health (NIH) interested in performing
a controlled experiment to determine the effects of caffeine on human blood pressure. One group
of people will get caffeinated coffee and one will get decaffeinated coffee. Briefly explain why
you would want that to be the only variable that differs between the two groups.

With the description of the different cell walls, membranes, and associated proteins set in the students' minds, you now need to introduce them to the idea that the cell wall can also act as a foundation to build things upon. bacterial appendages require a strong foundation that will offer the support needed to move and function in a dynamic world. for example, flagella are long, whiplike protein structures that are used by many gram-positive and gram-negative bacteria for locomotion. in order to function effectively, a flagellum must be firmly anchored to the cell wall. how will you be able to get across the idea that the peptidoglycan cell wall is strong enough to support such a mechanism? with a protein rod that passes through the cell wall and protein rings used to anchor it in the membranes, these basal bodies are the rudimentary biological motors that use atp power to spin the hook and the flagella attached to it. bacterial flagella have a biological motor that spins within the cell wall and is powered by atp. this allows the flagella to spin in a whiplike motion to propel the bacterium.

Why is excretion necessary to maintain homeostasis?

Which statement describes john tuzo wilson’s contribution to the theory of plate tectonics?