Please answer all of the following questions as clearly as possible.

 You are studying the effects of calcium levels on muscle contraction by observing calcium transport protein mutants. Each mutant you are studying is able to transport Ca²⁺ ions but at a much slower rate than normal. There is one transport protein (A) in the sarcolemma and two (B and C) in the sarcoplamic reticulum membrane diagrammed below. Tell whether each mutation (by itself) would increase, decrease or have no effect on muscle contraction.

a. Transport protein A _______________________________________________________________________

b. Transport protein B _______________________________________________________________________

c. Transport protein C _______________________________________________________________________

 Help! You are studying the properties of tubulin and actin in vitro but you have mixed up the tubes containing the samples of tubulin and actin. Describe how you could distinguish which tube holds each protein.

 Answer the following questions pertaining to the diagram below: Replicated chromosomes are separated by capture of growing microtubules.

a. Which end (minus or plus) of the tubule is reaches the chromosomes? ______________________________________

b. One model of chromosomal movement states that the chromosomes are attached to a motor protein and this protein moves along the MT pulling the chromosome with it. If this model is correct which motor molecule most likely is associated with the chromosomes?
 
 

c. What would you expect to happen to these chromosomes if you add taxol to this cell?
 
 

d. What would you expect to happen to the chromosomes if you deprive these cells of GTP (and they have no way to synthesize it) for several hours before dividing?
 
 
 
 

 Indicate whether each condition listed below will affect skeletal and or smooth muscle contraction by wrtiting "no" for contraction is normal or "yes" for contraction is impaired in any way.
 
 

	Skeletal Muscle	Smooth Muscle
T tubules are impermeable to Ca2+
Myosin cannot bind to Pi
A band is not uniform in length within a sarcomere
Troponin cannot bind to calcium
Calcium transporters are missing from plasma membrane
Cell cannot metabolize creatine phosphate