function deriv = dydt_tyson(t,statevar)

global k1norm k2 k3 k4prime k4 k5 k6 k7 k8 k9 ;

Y = statevar(1) ;
YP = statevar(2) ;
C2 = statevar(3) ;
CP = statevar(4) ;
M = statevar(5) ;
pM = statevar(6) ;

k1 = k1norm*(C2 + CP + pM + M) ;

CT = C2 + CP + pM + M ;

dY = k1 - k2*Y - k3*CP*Y ;

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% % You have to fill in some lines here
% % Enter the equations for the derivatives, as with the equation for dY
% % One equation for dYP, another for dC2, another for dCP, etc.
% % Some depend on total [CDC2], conveniently calculated above (CT)
% % Then, put all the derivatives into a single column vector called
% %   'deriv'
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return