BME 205 mid term solution
3. The cytoskeleton is made up of elaborate arrays of protein fibers, which form networks
throughout the cytosol.
A. What general function does the cytoskeleton perform?
Answer: A scaffold for the cell – providing structure, motility, and partitioning the
cytosol.
B. What are the three major types of protein filaments that make up the cytoskeleton and
what are their primary functions?
Answer: microfilaments – structural support & motility; microtubules - structural
support, motility, cell polarity, & chromosomes; intermediate filaments – support for
nuclear membrane, cell adhesion, motility.
4. The F-class proton pump is one of a family of ATP powered pumps involved in the
transport of ions and various small molecules against their concentration gradients.
A. How is the typical operation of the F-class proton pump different from the other
“ATP powered” pumps?
Answer: It synthesizes ATP
B. In a mammalian cell, which membrane are you most likely to find this pump on?
Answer: the inner mitochondrial membrane.
C. This pump, as indicated by its name, is involved in proton transport. Name two
strategies the cell can use to operate this pump without generating an electrical
potential across the relevant membrane.
Answer: 1) allow the parallel flow of anions such as Cl-; 2) engage in the anitparallel
movement of equal numbers of a different cation (such as K+)