mediated transport)</span>
<span class="r-out co"><span class="r-pr">#&gt;</span>          cellular_component</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> 1                      &lt;NA&gt;</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> 2                      &lt;NA&gt;</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> 3                      &lt;NA&gt;</span>
<span class="r-out co"><span class="r-pr">#&gt;</span> 4                      &lt;NA&gt;</span>
<span