  We have analysed the phenomenological dependence of the spin independent
($F_1^{p,n}$ and $F_2^{p,n}$) and the spin dependent ($g_1^{p,n}$) structure
functions of the nucleon on the the Bjorken scaling variable $x$ using the
unpolarized distribution functions of the quarks $q(x)$ and the polarized
distribution functions of the quarks $\Delta q(x)$ respectively. The chiral
constituent quark model ($\chi$CQM), which is known to provide a satisfactory
explanation of the proton spin crisis and related issues in the nonperturbative
regime, has been used to compute explicitly the valence and sea quark flavor
distribution functions of $p$ and $n$. In light of the improved precision of
the world data, the $p$ and $n$ longitudinal spin asymmetries ($A_1^p(x)$ and
$A_1^n(x)$) have been calculated. The implication of the presence of the sea
quarks has been discussed for ratio of polarized to unpolarized quark
distribution functions for up and down quarks in the $p$ and $n$ $\frac{\Delta
u^p(x)}{u^p(x)}$, $\frac{\Delta d^p(x)}{d^p(x)}$, $\frac{\Delta
u^n(x)}{u^n(x)}$, and $\frac{\Delta d^n(x)}{d^n(x)}$. The ratio of the $n$ and
$p$ structure functions $R^{np}(x)=\frac{F_2^n(x)}{F_2^p(x)}$ has also been
presented. The results have been compared with the recent available
experimental observations. The results on the spin sum rule have also been
included and compared with data and other recent approaches.
