Biology / Unit 4 Bio 0795 short lesson, about 20 seconds
Upstream and Downstream in a Signaling Cascade
Captions available
The idea
A signaling pathway, or cascade, is a chain reaction of activated proteins and messengers; earlier events are upstream, and events they trigger later are downstream.
In practice
A growth factor binding its receptor is upstream of the gene expression change that binding eventually causes.
Where people slip
A pathway can branch, so "downstream" only fixes an event's position relative to one specific upstream trigger.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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