Define the following terms:
$(1)$ Photorespiration
$(2)$ Bundle sheath

(N/A) $(1)$ Photorespiration: It is a light-dependent process occurring in chloroplasts where the enzyme $RuBisCO$ acts as an oxygenase instead of a carboxylase,leading to the consumption of $O_2$ and the release of $CO_2$ without the production of $ATP$ or $NADPH$.
$(2)$ Bundle sheath: These are specialized layers of cells (parenchymatous or sclerenchymatous) that surround the vascular bundles in the leaves of plants,particularly prominent in $C_4$ plants where they are the site of the Calvin cycle.