  We review the trade-offs between speed, fluctuations, and thermodynamic cost
involved with biological processes in nonequilibrium states, and discuss how
optimal these processes are in light of the universal bound set by the
thermodynamic uncertainty relation (TUR). The values of the uncertainty product
$\mathcal{Q}$ of TUR, which can be used as a measure of the precision of
enzymatic processes realized for a given thermodynamic cost, are suboptimal
when the substrate concentration $[S]$ is at the Michaelis constant
($K_\text{M}$), and some of the key biological processes are found to work
around this condition. We illustrate the utility of $\mathcal{Q}$ in assessing
how close the molecular motors and biomass producing machineries are to the TUR
bound, and for the cases of biomass production (or biological copying
processes) we discuss how their optimality quantified in terms of $\mathcal{Q}$
is balanced with the error rate in the information transfer process. We also
touch upon the trade-offs in other error-minimizing processes in biology, such
as gene regulation and chaperone-assisted protein folding. A spectrum of
$\mathcal{Q}$ recapitulating the biological processes surveyed here provides
glimpses into how biological systems are evolved to optimize and balance the
conflicting functional requirements.
