  We analyze recent measurements of the nucleon quark sea isospin asymmetry in
terms of the chiral quark model. The new measurements indicate that the SU(3)
model with modest symmetry breaking and no $\eta'$ Goldstone boson gives a
satisfactory description of data. We also discuss the matching parameter for
the axial-vector current. Finally, we analyze the nucleon quark spin
polarization measurements directly in the chiral quark model without using any
SU(3) symmetry assumption on the hyperon axial-vector form factors. The new
data indicate that the chiral quark model gives a remarkably good and
consistent description of all low energy baryon measurements.
