function EQ_Get_Next_States(index)

% Variables
global mRNAa;
global A;
global A2;
global Pz;
global PzA2;
global PzA4;
global mRNAz;

global l1;


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%% Function Definition
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% update species concentrations based on which reaction occured
switch index
    
    case {1}
        A = A + 1;        
    case {2}    
        mRNAa = mRNAa - 1;
    case {3}
        if( A > 1 )
            A2 = A2 + 1;
            A  = A - 2;
        end
    case {4}
        A = A - 1;
    case {5}
        A2 = A2 - 1;
        A = A + 2;
    case {6}
        A2 = A2 - 1;
    case {7}
        PzA2 = PzA2 + 1;
        Pz = Pz - 1;
        A2 = A2 - 1;
    case {8}
        PzA2 = PzA2 - 1;
        Pz = Pz + 1;
        A2 = A2 + 1;
    case {9}
        PzA2 = PzA2 - 1;
        Pz = Pz + 1;
    case {10}
        PzA4 = PzA4 - 1;
        PzA2 = PzA2 + 1;
    case {11}
        PzA4 = PzA4 + 1;
        PzA2 = PzA2 - 1;
        A2 = A2 - 1;
    case {12}
        PzA4 = PzA4 - 1;
        PzA2 = PzA2 + 1;
        A2 = A2 + 1;
    case {13}
        mRNAz = mRNAz + 1;
    case {14}
        mRNAz = mRNAz - 1;
    case {15}
        mRNAa = mRNAa + 1;
end